CN111156006A

CN111156006A - Construction method for shield underpass of dangerous pipeline

Info

Publication number: CN111156006A
Application number: CN201911297338.7A
Authority: CN
Inventors: 朱斌; 田作华; 姚义; 王天武; 周祖斌; 廖友根; 刘光雨; 肖祥; 王丙吉; 蒋华; 李�杰; 刘红建
Original assignee: China Railway 22nd Bureau Group Co Ltd; China Railway 22nd Bureau Group Urban Rail Engineering Co., Ltd.
Current assignee: China Railway 22nd Bureau Group Co Ltd; China Railway 22nd Bureau Group Urban Rail Engineering Co., Ltd.
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-05-15

Abstract

The invention discloses a construction method for a shield tunneling pipeline, comprising the following steps: step 1: on-site inspection; step 2: monitoring surface subsidence and uplift; step 3: monitoring the deformation of buildings (structures); step 4: monitoring soil Body layering, vertical displacement. In the present invention, improvement measures are carried out for each step, so that the construction of underpassing complex buildings in the shield tunnel section realizes the purpose of safe underpassing.

Description

Construction method for shield underpass of dangerous pipeline

Technical Field

The invention relates to the field of tunnel construction, in particular to a construction method for a shield underpass dangerous pipeline.

Background

Under the urban ground surface, in the construction of dangerous source pipelines penetrating through underground tunnels, innovative construction methods for special construction sections are needed, and the construction of the existing dangerous pipelines penetrating through the underground tunnels around shields is improved, so that the aims of quick and safe construction are fulfilled.

Disclosure of Invention

The invention aims to solve the technical problem of providing a construction method for a shield underpass dangerous pipeline and a new construction method.

The technical problem to be solved by the invention is realized by the following technical scheme:

a shield underpass pipeline construction method comprises the following steps:

(1) optimizing the tunneling parameters of the underpass dangerous source pipeline, the ground settlement control standard and the pipeline settlement control standard, finding out the relative relation between the construction environment and the tunneling parameters, wherein the two types of geology of the lower side and the side-penetrating dangerous source pipeline section of the interval are full-face mudstone strata and composite strata of upper sand pebble lower mudstone, and the optimal setting of the tunneling parameters is respectively as follows:

the tunneling parameters of the full-face mudstone stratum shield downward penetration or side penetration pipeline are as follows:

the tunneling parameters of the composite stratum shield lower/side through pipeline of the mudstone at the lower part of the upper pebble are as follows:

the dangerous source is a rainwater pipe, an electric power pipeline, a high-pressure gas pipe and a sewage pipe;

(2) reinforcing a downward-penetrating dangerous source pipeline;

(3) monitoring the surface settlement;

(4) monitoring the settlement of the underground pipeline;

(4) and setting a monitoring control reference and an alarm value.

Preferably, the shield is provided with a rainwater pipe and a power pipeline for reinforcing, and the method comprises the following steps:

(1) before the shield passes through the pipeline, the machine condition is checked by stopping the machine at the position of 10m, and the opening of a bin checking cutter ensures that the shield continuously tunnels when passing through a dangerous source;

(2) controlling tunneling parameters: determining the distance between a rainwater pipe and an electric power pipeline and the position relation between the rainwater pipe and an interval tunnel, controlling the tunneling soil pressure fluctuation within the range of 0.1bar in the construction process, and using foam soft soil pressure;

(3) the foaming agent and the water adding amount are increased to ensure the improvement of the residue soil and control the residue output amount; in the shield tunneling process, the soil output is uniformly controlled according to the footage and the soil pressure, and the soil output is matched with the grouting amount;

(4) according to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, secondary grouting reinforcement is carried out on the back of the upper part of the duct piece by using a double-liquid grouting machine, a building gap on the back of the duct piece is filled, and the setting time of synchronous grouting slurry is shortened; the stratum is reinforced by reserving grouting holes on the duct pieces, the reinforcing mode takes double-liquid slurry as a main part and single-liquid cement slurry as an auxiliary part, and the reinforcing is carried out in-hole grouting reinforcement within the range of 120 degrees of external expansion of the arch tops of the left-line and right-line tunnels by 1.5 m;

(5) high-quality shield tail grease is adopted, so that the sealing effect is improved, and the shield tail is prevented from leaking slurry;

(6) monitoring stress strain of the crossing section;

(7) the interval tunnel is used for additionally arranging grouting hole pipe pieces when passing through the section, and grouting is timely supplemented according to monitoring conditions to reinforce the stratum.

(8) Strengthening monitoring measurement, and monitoring the displacement and ground settlement of the electric power tunnel;

(9) and performing test tunneling construction before the shield construction passes through the electric power tunnel to obtain tunneling parameters for shield propulsion.

Preferably, the reinforcing of the shield underpass sewer pipeline comprises the following steps:

(1) before the shield passes through the pipeline, the machine condition is checked by stopping the machine at the position of 10m in front, and the shield is ensured to continuously tunnel when passing through a dangerous source by opening a cabin checking cutter.

(2) Controlling shield tunneling parameters: controlling the stratum loss rate within 2%, and ensuring that the shield propulsion soil pressure is not less than 0.8 time of the theoretical water and soil pressure; grouting synchronously in time after the shield passes through, controlling synchronous grouting amount and grouting pressure, and ensuring that the compressive strength of the unconfined single shaft is not less than 1 MPa; determining the mileage of the drainage pipeline and the position relation between the mileage and the interval tunnel;

(3) the improvement effect of the muck is ensured by adding a foaming agent and water, the output muck is controlled, the rotating speed and the propelling speed of a cutter head are reduced, the shield is ensured to pass through at a constant speed, and the soil pressure is properly improved;

(4) according to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, secondary grouting reinforcement is carried out on the back of the upper part of the duct piece by using a double-liquid grouting machine, a building gap on the back of the duct piece is filled, and the setting time of synchronous grouting slurry is shortened; the method comprises the following steps of reinforcing in-hole grouting measures, namely reinforcing the stratum through a grouting hole reserved in a duct piece, wherein the reinforcing mode takes double-liquid slurry as a main single-liquid cement slurry as an auxiliary mode to reduce the influence of a shield machine on a pipeline structure; the grouting reinforcement length in the holes of the left line and the right line is 30 meters; and after the shield passes through, determining whether to perform tracking grouting according to the measured result of the monitored quantity. Reinforcement range: the reinforcing range of the front-passing section is that the secondary grouting in the tunnel is carried out within the range of 360 degrees outward expansion 1.5m around the tunnel;

(6) monitoring stress strain of the crossing section;

(7) the section of thick bamboo is used when tunnel passes through this section to increase the slip casting hole section of jurisdiction, in time supplements the slip casting according to the monitoring conditions and consolidates the stratum.

Preferably, the shield is downwards penetrated and embedded with a high-pressure gas pipe pipeline for reinforcement, and the method comprises the following steps:

(1) the shield tunneling parameters are strictly controlled, and the stratum loss rate is controlled within 2 percent, and the shield propelling pressure is not less than 0.8 time of the theoretical water and soil pressure. Timely and synchronously grouting after the shield passes through, and controlling synchronous grouting amount and grouting pressure by paying attention to the control, wherein the unconfined uniaxial compressive strength is not less than 1MPa, and the gas pipeline mileage and the position relation with the interval tunnel are determined;

(2) the slag discharge amount is strictly controlled by increasing the foaming agent and the water addition amount to ensure the slag soil improvement effect, the rotating speed and the propelling speed of the cutter head are reduced to ensure that the shield passes through at a constant speed and the soil pressure is properly improved;

(3) according to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, selecting a proper time to carry out secondary grouting reinforcement on the back of the upper part of the duct piece by using a double-liquid grouting machine, filling a building gap on the back of the duct piece and shortening the solidification time of synchronous grouting slurry; secondary grouting reinforcement is carried out in the left line hole and the right line hole on the duct piece by additionally arranging grouting holes, the left line and the right line of the reinforcement length are both 10 meters, and the reinforcement range of the lower penetrating section is that the secondary grouting is carried out in the hole within the range of extending out by 360 degrees around the tunnel by 1.5 m;

(4) high-quality shield tail grease is adopted, so that the sealing effect is improved, and the shield tail is prevented from leaking slurry;

(5) monitoring stress strain of the crossing section;

(6) the section of thick bamboo is used when tunnel passes through this section to increase the slip casting hole section of jurisdiction, in time supplements the slip casting according to the monitoring conditions and consolidates the stratum.

Preferably, the shield side sewer pipeline reinforcement comprises the following steps: the shield construction of the sewage pipe adopts line adjustment, drainage, isolation or reinforcement, a centralized drainage mode is adopted, a submersible sewage pump is used as pumping and drainage equipment, and sewage is discharged after a sewage main pipe is plugged by the submersible sewage pump;

(1) the shield tunneling parameters are strictly controlled, and the stratum loss rate is controlled within 2 percent, and the shield propelling pressure is not less than 0.8 time of the theoretical water and soil pressure. And (3) timely and synchronously grouting after the shield passes through, and controlling the synchronous grouting amount and the grouting pressure by paying attention to the unconfined uniaxial compressive strength not less than 1 MPa.

(2) The cement slurry ratio and the grouting pressure parameter should be subjected to a principle of testing before grouting, and the water cement ratio is 1: 1; the unconfined compressive strength of the grouting reinforced soil body 28d is not less than 1MPa, and the permeability coefficient is not more than 10-6/cm/s.

(3) Adding a grouting hole on the duct piece to perform secondary grouting reinforcement in the tunnel;

(4) the shield carries out informatization construction through the whole process, and closely monitors the displacement condition and ground settlement of the building;

(5) and performing experimental tunneling construction before penetrating the construction on the shield construction side to obtain shield tunneling parameters.

Preferably, the monitoring of surface subsidence comprises the steps of:

laying surface settlement monitoring points: drilling a hole in the soil layer 2, arranging a twisted steel mark point 5 in the hole, wherein the length of the twisted steel mark point is more than 90cm, filling coarse sand 3 between the twisted steel and the soil layer, and arranging a protective cover 6 above the drilled hole; drilling holes penetrate through a pavement structure layer, the diameter of each drilling hole is 80-130mm, the depth is about 1m, the length of each twisted steel bar is more than 100cm, each twisted steel bar is taken as a mark point, the coarse sand surface of the filler is exposed by about 1-2 cm, and the diameter of the steel protective cover is more than 110 mm; maintaining for more than 15 days;

observing in a single way when a closed leveling route is adopted, observing in a reciprocating way in an attached leveling route mode, and performing adjustment by taking the number of height differences observed twice; and (3) observation sequence: and (3) testing: back, front, back; and (3) return measurement: front, back, front.

Preferably, the method comprises the following steps: underground pipeline monitoring points are arranged on the pipeline, at positions corresponding to projects or on corresponding surface buried indirect observation points, and particularly, the arrangement distance is 25m at the nodes, corner points or parts sensitive to displacement change of the pipeline;

the underground pipeline settlement monitoring point burying method comprises the following steps: drilling a ground hardened layer completely by adopting a water drill for a closed pipeline, excavating holes to an outer protective wall of the pipeline 1, putting a steel bar 5 into the periphery of the pipeline and filling the periphery of the pipeline with fine sand 3, covering a steel protective cover 5 on the position of the steel bar 5 to protect a measuring point, and filling the fine sand 3 at the measuring point; and (4) for the open pipeline, a monitoring point support is arranged on the pipeline or the pipeline buttress.

Preferably, the setting of the monitoring control reference and the alarm value comprises the following steps:

two control indexes of monitoring variable accumulated value and change rate are adopted, and the parameters are as follows:

preferably, the method further comprises the following steps: carrying out monitored feedback, report, disposal and alarm elimination emergency rescue measures, wherein the electric power tunnel emergency measures are as follows:

(1) reinforcing the electric power tunnel: adopting grouting to reinforce the soil body within the range of 5.0m around the electric power tunnel, adopting pure cement slurry as a ground grouting material, wherein the grouting pressure is 0.2-0.4 MPa, and the soil body reinforcing depth is 5.0 m:

grouting in the holes of the electric power tunnel for reinforcement: pure cement slurry is adopted. Grouting pressure is 0.2-0.4 MPa;

(2) emergency measures for abnormal rain and sewage pipes: ground grouting and secondary slurry supplement at the back of a tunnel inner pipe sheet are adopted;

(3) emergency measures for gas pipeline accidents:

reinforcing the gas pipeline: adopting grouting in the range of 5.0m around the pipeline to reinforce the soil body, adopting pure cement slurry as a ground grouting material, wherein the grouting pressure is 0.2-0.4 MPa, and the soil body reinforcement depth is 8.0 m;

grouting in the holes for reinforcement: pure cement slurry is adopted, and the grouting pressure is 0.2-0.4 MPa.

In the present invention, the above or below certain numerical value is a preferable numerical value including the numerical value.

Compared with the prior art, the invention has the following advantages:

the method comprises the steps of (1) optimizing tunneling parameters, ground settlement control standards and pipeline settlement control standards of the underpass dangerous source pipeline, and finding out the relative relation between the construction environment and the tunneling parameters; (2) reinforcing a downward-penetrating dangerous source pipeline; (3) monitoring the surface settlement; (4) monitoring the settlement of the underground pipeline; (5) and setting monitoring control reference, alarm value and the like, and repeatedly testing and exploring the underground hazard source pipeline tunnel construction of the composite stratum of the section shale stratum and the upper sand-gravel lower shale stratum so as to achieve the purpose of quick and safe construction.

Drawings

FIG. 1-1 is a plan view of a shield tunnel, a rain pipe and a power line

FIGS. 1-2 are schematic views showing examples of reinforcing in a tunnel of a down-penetrating rain pipe of an interval tunnel

FIG. 2-1 is a diagram of an embodiment of a planar position relationship between a shield interval tunnel and a pipeline of a newly-built sewage treatment plant

FIG. 2-2 is DN3200 sewage tunnel section view

FIG. 2-3 is a schematic view of reinforcing a pipeline of a newly-built sewage treatment plant under a shield

FIG. 3 is a shield and constructs DN1016 high-pressure gas pipe reinforcement schematic diagram of wearing down

FIG. 4 is a schematic view of reinforcing a shield-driven downward-penetrating sewage pipe

FIG. 5 is a vertical layout view of the horizontal pipeline and the water pump from the sewage inspection well to the inspection well

FIG. 6 is a schematic structural view of the device for monitoring surface subsidence of the present invention

FIG. 7 is a schematic view of the underground pipeline settlement monitoring device of the present invention

1-pipeline, 2-soil layer, 3-sand layer, 4-steel pipe protection well, 5-twisted steel bar mark points with the diameter of 18mm and 6-steel protection cover.

Detailed Description

Referring to fig. 1-1, fig. 1-2, fig. 2-1, fig. 2-2, fig. 2-3, fig. 4, fig. 5, fig. 6 and fig. 7, a shield underpass pipeline construction method is carried out in a shield zone from a Chengdu stone road station to a three-color road station, and the stratum penetrated by the tunnel in the shield zone is mainly mudstone. The shield region from the gold stone road station to the three-color road station to the neutralization station mainly comprises a downward-penetrating pipeline: the pipeline of a sewage treatment plant, the planning pipeline of a high-pressure gas pipe and the sewage pipe are newly built, and the ground conditions along the pipeline are complex. As shown in fig. 1-1.

4 phi 6280 earth pressure balance shield machines are adopted in the shield section of the standard section, and the construction step of the shield underpass pipeline is as follows:

1. and (3) ensuring continuous tunneling during construction preparation and downward penetration:

before the shield machine passes through a dangerous source, the shield machine and the rear supporting equipment are overhauled comprehensively and carefully once. The gravity center overhauls a grouting system, a control circuit, a hydraulic system, a shield tail brush, a gantry crane braking system, a traveling system, a battery car brake and a circuit of the shield tunneling machine. And the damaged parts are immediately replaced, the parts with the fault hidden danger are timely eliminated, and lubricating grease or lubricating oil is timely filled into each lubricating part. Especially wash the mediation to the slip casting pipeline, avoid the conveyer pipe to block up during the shield is worn the risk source down, lead to the thick liquid supply to break off to cause the shield structure machine to shut down, monitor shield tail sealing system simultaneously, thereby guarantee not take place the slip casting phenomenon and guarantee the grouting volume when wearing down.

The main material of shield construction is reinforced concrete lining segment, the segment is special for down-passing pipeline, waterproof material, slurry mixing raw material including cement, sand, fly ash and bentonite, the stock quantity of various raw materials is counted before down-passing pipeline, the sufficient quantity is ensured, the stock quantity of each raw material is closely monitored during the passing period of the shield, the stock quantity of the material in the warehouse is counted every day, the material is immediately supplemented when the quantity is lower than the warehouse capacity 1/2, the quality of the raw material is strictly controlled, and unqualified material entering is firmly stopped. During construction, the influence of weather conditions on material supply is considered, the weather conditions in the next two days are concerned every day, and the raw materials influenced by the weather are reserved in advance.

Technical preparation

When a pipeline is penetrated through the lower/side of the golden-three-middle area, the main work in the technical aspect is to optimize tunneling parameters, analyze geological conditions, hydrological conditions, tunnel covering soil thickness, relative positions of the pipeline and a building structure and the like in a penetrating range, determine reasonable tunneling parameters, control ground settlement and pipeline settlement and achieve the purpose of protecting the pipeline penetrated through the lower/side. In order to find out the relative relation between the construction environment and the tunneling parameters, the tunneling parameters and the ground settlement monitoring values in the early construction process are analyzed and summarized, so that the construction parameters in the tunneling project are determined, and the sections of the downward-penetrating pipeline and the side-penetrating pipeline in the interval are divided into two types: the tunneling parameters of the full-face mudstone stratum and the composite stratum of the upper sand pebble and the lower mudstone are optimized according to the following tables: and performing technical interaction on all field managers and operation layers, so that each constructor can completely understand the technical requirements of the shield in the stage of crossing the dangerous source.

Underground/side pipeline tunneling parameter optimization table for gold-to-three-middle area mudstone stratum shield

Composite stratum shield lower/side pipeline tunneling parameter optimization table for upper pebble lower mudstone between gold and three-middle areas

Meanwhile, the slag improvement is made in the downward-penetrating construction stage, the slag square amount and the weighing are controlled in a slag improvement mode combining foam and bentonite, and the good fluidity is achieved; low permeability; reduce the torque of the cutter head, reduce the abrasion of the cutter and have good lubricity. The position and the quantity of the improved muck directly influence the state of the muck in the soil bin and the probability of mud cake formation.

Servicing of equipment

In the lower/side pipeline penetration construction, the construction continuity is important. Before the shield machine passes through the pipeline at the lower side or the side, the equipment is comprehensively and systematically overhauled at the position 50m in front, a gantry crane, a mixing plant, rear corollary equipment, an electric system and a hydraulic system in the shield machine are overhauled, easily damaged parts are purchased in advance to be used as emergency spare parts, and smooth pipeline passing through the lower side or the side without stopping continuous tunneling is ensured.

2. Rain pipe and power pipeline under shield (gold-three section)

Spatial position relationship: the left line and the right line of the interval tunnel in the range of mileage YDK42+813.00 ~ 840.000(ZDK42+813.000 ~ 840.000) respectively penetrate rainwater pipe and 220kv electric power pipeline, and the size of the bricking rainwater pipe is: 2100mmx2300mm, 220kv power pipeline size is: 2200mmx2000 mm. Rainwater and electric power pipeline all lay along the great road of the jinjiang river, and the rainwater pipe buries deeply about 2m, and electric power pipeline buries deeply about 4 m. The soil of the tunnel in the shield region is about 15m, the distance between the rainwater pipe and the top of the tunnel is about 10.9m, and the distance between the power pipe and the top of the tunnel is about 9.3 m.

As shown in fig. 1-2, shield construction protection measures are as follows:

shield construction control:

when the shield is driven downwards, stratum deformation caused in the shield construction process is reduced as much as possible, and the method is an effective means for protecting pipelines, and the quality is mainly controlled in various aspects such as controlling driving parameters, improving grouting quality in a tunnel, monitoring and measuring and the like.

(1) Before the shield passes through the pipeline, the machine condition is checked by stopping the machine at the position of 10m, and if necessary, a warehouse opening check cutter is carried out to ensure that the shield continuously tunnels when passing through a dangerous source.

(2) And strictly controlling tunneling parameters. The distance between the rainwater pipe and the electric power pipeline and the position relation between the rainwater pipe and the electric power pipeline and the interval tunnel are determined, and the tunneling soil pressure is strictly controlled in the construction process. The soil pressure stability of a tunneling surface is strictly kept in the shield tunneling process, the soil pressure fluctuation is within the range of 0.1bar, the soft soil pressure such as foam is reasonably used, the running water of underground water is prevented, the settlement caused by shield tunneling and excavation is ensured to be within the allowable range, people are sent to pay close attention to the soil pressure change when the machine is stopped, and measures are taken in time when the preset value is exceeded. The earth pressure is kept uniform and prevented from being suddenly high or low. The shield machine driver needs to carefully operate in the operation process, and the propelling speed, the spiral rotating speed and the cutter head rotating speed are in smooth transition. The soil pressure control needs to be closely matched with the ground monitoring, and if the ground monitoring finds that the ground in front of the cutter head always rises and exceeds an early warning value, the soil pressure needs to be properly reduced at the moment; the earth pressure should be increased instead. The earth pressure ground monitoring forms a good feedback channel, so that a shield driver can adjust earth pressure control parameters in time.

(3) The foaming agent and the water adding amount are increased to ensure that the slag soil improvement effect strictly controls the slag output amount, the rotating speed and the propelling speed of the cutter head are reduced to ensure that the shield passes through at a constant speed and the soil pressure is properly improved. And in the shield tunneling process, the soil output is strictly and uniformly controlled according to the footage and the soil pressure, and the soil output is matched with the grouting amount.

(4) According to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, selecting a proper time to carry out secondary grouting reinforcement on the back of the upper part of the duct piece by using a double-liquid grouting machine, filling a building gap on the back of the duct piece and shortening the solidification time of synchronous grouting slurry;

(6) monitoring stress and strain of the crossing section, arranging a specially-assigned person to carry out surface inspection and monitoring

(7) When the interval tunnel passes through the section, the A-shaped additional grouting hole duct piece is used, and grouting is timely supplemented according to the monitoring condition to reinforce the stratum.

(8) And (4) strengthening monitoring and measuring, wherein the shield constructs through the process to implement full-information construction, and closely monitors the displacement and ground settlement of the electric tunnel.

(9) The experimental tunneling construction is carried out before the shield construction passes through the electric power tunnel, so that necessary tunneling parameters such as shield propelling pressure, ground settlement and the like are obtained, and information construction is carried out.

In-hole reinforcement measures

After a shield penetrates through a 220KV power pipe and a rainwater pipe, grouting measures in a tunnel are enhanced, grouting holes are reserved in duct pieces to reinforce the stratum, and the reinforcing mode takes double-liquid slurry as main single-liquid slurry as auxiliary to reduce the influence of a shield machine on a pipeline structure. And (3) carrying out grouting reinforcement in the tunnel within the range of 1.5m by expanding the arch tops of the left and right tunnels at 120 degrees, wherein the left and right lines of the grouting reinforcement length are both 27m (YDK42+ 813.000-840.000 (500 rings-519 rings), ZDK42+ 813.400-840.000 (497 rings-516 rings)).

3. A DN2200 regeneration pipe, a DN2400 draft pipe and a DN3200 sewage tunnel (three middle intervals) are penetrated downwards, as shown in figure 2-1, figure 2-2 and figure 2-3.

Spatial position relationship

The shield interval tunnel passes through four pipelines of a newly-built sewage treatment plant in the range of Y (Z) DK45+ 010-Y (Z) DK45+040, and the four pipelines are respectively: 1, a regeneration tube DN2200 is made of PCCP (prestressed concrete cylinder pipe) with the wall back 300mm and the buried depth 5.4 m; 2, two draft tubes DN2400 made of PCCP (prestressed concrete cylinder pipe) tubes with the wall back 300mm and the buried depth of 7.5 m; 3> sewage tunnel DN3200, the material is reinforced concrete pipe, 320mm behind the wall, buried depth 12.4 m. The soil of the tunnel in the shield zone is about 18.9m in the range of the downward penetrating pipeline, the minimum distance from the bottom of the pipeline is 6.4m, the stratum of the downward penetrating zone is filled with miscellaneous filling soil, pebbles and mudstones from top to bottom in sequence, and the stratum penetrated by the tunnel is weathered mudstone.

The main protection measures of the shield interval are as follows:

shield construction control

When the shield is driven downwards, stratum deformation caused in the shield construction process is reduced as much as possible, and the method is an effective means for protecting drainage pipelines, and the quality is mainly controlled in various aspects such as controlling driving parameters, improving grouting quality in a tunnel, strengthening monitoring and measuring and the like.

(1) Before the shield passes through the pipeline, the machine is stopped at the position of 10m, and the condition is checked, and if necessary, a warehouse opening check cutter is carried out to ensure that the shield continuously tunnels when passing through a dangerous source.

(2) The shield tunneling parameters are strictly controlled, which mainly includes that the stratum loss rate is controlled within 2 percent, and the shield propelling soil pressure is not less than 0.8 time, such as 0.8-2 times of theoretical water and soil pressure. And (3) timely and synchronously grouting after the shield passes through, and controlling the synchronous grouting amount and the grouting pressure by paying attention to the control, wherein the compressive strength of the unconfined single shaft is not less than 1MPa, such as 1-5 MPa. Determining the mileage of the drainage pipeline and the position relation between the mileage and the interval tunnel;

(3) the slag discharge amount is strictly controlled by increasing the foaming agent and the water addition amount to ensure the slag soil improvement effect, the rotating speed and the propelling speed of the cutter head are reduced to ensure that the shield passes through at a constant speed and the soil pressure is properly improved;

(4) according to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, selecting a proper time to carry out secondary grouting reinforcement on the back of the duct piece (upper part) by using a double-liquid grouting machine, filling a building gap on the back of the duct piece and shortening the solidification time of synchronous grouting slurry;

(6) monitoring stress and strain of the crossing section, and arranging a specially-assigned person to perform surface inspection and monitoring;

(7) the A-type grouting hole segment is added when the interval tunnel passes through the section, and grouting is timely supplemented according to the monitoring condition to reinforce the stratum.

In-hole reinforcement measures

After the shield is put through the newly-built sewage plant pipeline, the grouting measures in the tunnel are strengthened, the grouting holes are reserved through the duct pieces to reinforce the stratum, and the reinforcing mode takes the double-liquid slurry as main single-liquid cement slurry to assist in reducing the influence of the shield machine on the pipeline structure. The grouting reinforcement length in the holes of the left line and the right line is 30 meters. And after the shield passes through, determining whether to perform tracking grouting according to the measured result of the monitored quantity.

And the reinforcing range of the positive penetrating section in the reinforcing range (1) is that secondary grouting is carried out in the tunnel within the range of extending for 1.5m around the tunnel by 360 degrees. (2) The left line hole internal reinforcement section ZDK45+ 010.000-ZDK 45+040.000(788 ring-808 ring), the right line hole internal reinforcement section YDK45+ 010.000-YDK 45+040.000(789 ring-809 ring).

4. The shield is downwards penetrated to plan DN1016 high pressure gas pipe (three-middle section), as shown in figure 3.

Spatial position relationship

The shield interval tunnel penetrates through a DN1016 high-pressure gas pipeline under Y (Z) DK45+ 230.000-Y (Z) DK45+240. DN1016 high-pressure gas pipe material is the steel pipe, and the maximum buried depth of the pipe bottom is 9.1 m. The pipe is a D1016x19.5mmL415M longitudinal submerged arc welded steel pipe, the design pressure is 4.0MPa, protective measures are required to be considered during pipeline construction, and the influence of subway sections on the pipe is reduced. If the pipeline is not buried as the shield passes through the range, the in-tunnel reinforcement measures may not be implemented. The earth covering of the shield interval tunnel is about 23.2m, and the minimum distance from the shield interval tunnel to the bottom of the pipeline is 14.1 m.

Main treatment measures

When the pipeline is laid before the shield tunnel construction, the shield tunnel penetrates through the pipeline in the range, the shield tunnel is covered with soil about 23.2m, and the minimum distance from the bottom of the pipeline is 14.1 m. DN1016 large-diameter high-pressure gas pipeline is penetrated below the shield tunnel, and the measures are mainly adopted as follows:

(1) the shield tunneling parameters are strictly controlled, which mainly reflects that the stratum loss rate is controlled within 2 percent and the shield propelling pressure is not less than 0.8, such as 0.8-2 times of the theoretical water and soil pressure. And (3) timely and synchronously grouting after the shield passes through, and controlling the synchronous grouting amount and the grouting pressure by paying attention to the control, wherein the compressive strength of the unconfined single shaft is not less than 1MPa, such as 1-51 MPa. Determining gas pipeline mileage and the position relation between the gas pipeline mileage and an interval tunnel;

(3) according to the settlement condition and the tunneling condition of the ground surface, when the duct piece is dragged out of a 5-10 ring shield tail, selecting a proper time to carry out secondary grouting reinforcement on the back of the duct piece (upper part) by using a double-liquid grouting machine, filling a building gap on the back of the duct piece and shortening the solidification time of synchronous grouting slurry;

(5) monitoring stress and strain of the crossing section, and arranging a specially-assigned person to perform surface inspection and monitoring;

(6) the A-type grouting hole segment is added when the interval tunnel passes through the section, and grouting is timely supplemented according to the monitoring condition to reinforce the stratum.

(7) And (3) reinforcing the left and right wire holes by secondary grouting through additionally arranging grouting holes on the duct piece, wherein the reinforcing lengths of the left and right wires are 10 meters (Y (Z) DK45+ 230.000-Y (Z) DK45+240.000), the left wire is 935 in a ring-942, and the right wire is 936 in a ring-942. And the reinforcing range of the lower penetrating section is that the secondary grouting in the tunnel is carried out within the range of 360-degree outward expansion 1.5m around the tunnel. The specific reinforcement ranges are shown in the following figures:

(8) and (4) strengthening monitoring and measuring, wherein the shield constructs the information construction in the whole process, and closely monitors the displacement condition and ground settlement of the constructed structure.

5. DN1400 sewage main pipe and shops along the street (three-middle section) are penetrated by the shield side, as shown in figures 4 and 5.

Spatial position relationship

The shield interval tunnel passes through DN1400 sewer pipe under Y (Z) DK46+ 040.000-Y (Z) DK46+ 050.000. DN1400 sewer pipe is made of reinforced concrete pipe with wall thickness of 140mm, the maximum buried depth is about 10.3m, the pipeline design stage is in butt joint with subway, and steel sleeve is added in the downward penetration range of the interval. DN1400 sewer pipe is penetrated downwards in the shield region, the shield tunnel is covered with soil about 17.1m, and the minimum distance from the shield tunnel to the bottom of the pipeline is about 6.8 m.

Main treatment for lower wearing

DN1400 sewage pipes penetrate through the shield interval tunnel in the range from three to middle, the shield tunnel is covered with soil about 17.1m, and the minimum distance from the shield tunnel to the bottom of the pipeline is about 6.8 m. The shield tunnel closely passes through DN1400 large-diameter sewage pipe, and the key measures are as follows:

(1) the distance from the three-color road station to the neutralization station to the number #3 contact channel is YDK45+850.000(ZDK45+848.957), the distance from the distance to the shield starting end is 2047.506m, and the distance from the distance to the contact channel is 1363-1367 rings, the distance from the contact channel is also used as a tool changing point, before a DN1400 sewer pipe is downwards penetrated or laterally penetrated, the distance from the ring 137 at the position of the downwards penetrating pipeline is used for checking and changing the tool at the tool changing point, and the normal tunneling of the shield tunneling machine is ensured during the downwards penetrating or laterally penetrating of the sewage pipeline.

(2) The shield tunneling parameters are strictly controlled, and the stratum loss rate is controlled within 2 percent, and the shield propelling pressure is not less than 0.8 time of the theoretical water and soil pressure. And (3) timely and synchronously grouting after the shield passes through, and controlling the synchronous grouting amount and the grouting pressure by paying attention to the unconfined uniaxial compressive strength not less than 1 MPa. Determining the mileage of the sewage pipeline and the position relation between the mileage and the interval tunnel;

(8) And (3) reinforcing the left and right wire holes by secondary grouting through additionally arranging grouting holes on the pipe piece, wherein the reinforcing lengths of the left and right wires are respectively 10 meters (Y (Z) DK46+ 040.000-Y (Z) DK46+050.000), the rings of the left wire 1473 and 1480 and the rings of the right wire 1476 and 1482. And the reinforcing range of the lower penetrating section is that the tunnel vault is expanded by 180 degrees by 1.5m for secondary grouting in the tunnel.

(9) And (4) strengthening monitoring and measuring, wherein the shield constructs the information construction in the whole process, and closely monitors the displacement condition and ground settlement of the constructed structure.

6. The main treatment for side threading is shown in fig. 5.

Aiming at DN1400 sewage pipe horizontal minimum distance tunnel 2010mm and vertical minimum distance tunnel 2300mm in the three-middle-area interval, the shield construction danger is large, effective measures such as line adjustment, drainage, isolation or reinforcement are adopted, the sewage pipe explosion danger is reduced, the line adjustment, isolation or reinforcement conditions are not provided through the research and discussion with the design and the geological exploration, the 2# inspection well sewage can be intensively drained into the 3# inspection well in a centralized drainage mode, and the condition that no water exists in the DN1400 sewage pipe in the range is ensured during the shield underpass or side-pierce construction.

DN1400 daily sewage flow checking calculation for sewage pipe

The designed flow of the sewage pipeline system is the maximum flow which can be ensured by the sewage pipeline and the accessory structures thereof. The maximum time-of-day flow is usually taken as the design flow for the sewer piping system, which is expressed in L/s. The method comprises two parts of domestic sewage design flow and industrial wastewater design flow. According to investigation, the sewage pipeline in the construction area only relates to domestic sewage.

DN1400 checking the flow of the full sewage pipe: according to the outdoor drainage design specification (GB 50014-2006), the design flow speed in the sewage pipe at full flow is 0.6-0.75 m/s. DN1400 sewage pipe sectional area S ═ Pi R²＝3.14*0.7²＝1.54m². Full pipe flow Q ═ S × V ═ 1.54m²*0.75m/s＝1.155m³/s＝4158m³/h。

Water pump configuration:

under the normal state: 2 sets of 50QW30-22-4 submersible sewage pumps are selected for standby use, the design flow is 30m3/h, the lift is 22m, the motor power is 4.5kw, and the water outlet pipe diameter is 125mm, and the set is used as main pumping and drainage equipment in a normal state.

In the full pipe state: 3 WQ400-1800-32-250 submersible sewage pumps (one for standby) and 2 WQ300-600-20-55 submersible sewage pumps (1 for standby) are selected as main pumping and drainage equipment in a full pipe state.

A pumping and drainage system:

temporary plugging of a sewage pipe:

in order to ensure that water does not exist in the range of 80m of DN1400 sewage pipe between two inspection wells during the drainage from the 2# inspection well to the 3# inspection well, two ends of the sewage pipe are required to be plugged in advance, 24 walls are built in the sewage pipe, the edge joint position is sealed by plugging agent, and after a drainage pump and a pipeline are installed and debugged, the part is plugged.

Pipeline:

according to the condition of the water collecting amount in the sewage pipe, the selective water pumping equipment is combined, and a set of pipeline is adopted under the normal flow state of sewage in the pipe: the diameter is 125mm, the pipes are seamless steel pipes and are used as sewage pumping and draining pipelines in a normal state, when the sewage in the pipes is in a full pipe state, 3 groups of discharge pipes with the diameter of 400mm are adopted, one group is a standby pipeline, and 1 group of discharge pipes with the diameter of 300mm is used as a sewage pumping and draining pipeline in the full pipe state.

Side-piercing in-hole treatment

The shield tunnel between the three-middle areas penetrates through a DN1400 sewage pipe at the right line side and is close to a store along the street, the soil of the shield tunnel is about 12-16 m, the distance from the bottom of the pipeline is about 2.3-6.26 m, and the minimum distance from the right line tunnel to the store along the street is 2.0m (mileage: DK46+ 270). DN1400 large-diameter sewage pipe is penetrated by the close distance side of the shield tunnel, and the key measures are as follows:

1) the shield tunneling parameters are strictly controlled, and the stratum loss rate is controlled within 2 percent, and the shield propelling pressure is not less than 0.8 time of the theoretical water and soil pressure. And (3) timely and synchronously grouting after the shield passes through, and controlling the synchronous grouting amount and the grouting pressure by paying attention to the unconfined uniaxial compressive strength not less than 1 MPa.

2) The principle of testing and then making should be executed on the cement slurry ratio, grouting pressure and other parameters, and the water cement ratio is 1: 1. the unconfined compressive strength of the grouting reinforced soil body 28d is not less than 1MPa, and the permeability coefficient is not more than 10-6/cm/s.

3) Add the slip casting pore pair tunnel on the section of jurisdiction and carry out secondary slip casting in the hole and consolidate, the reinforcing range: (ZDK46+ 105-135, YDK46+ 205-295).

4) And (4) strengthening monitoring and measuring, wherein the shield constructs the information construction in the whole process, and closely monitors the displacement condition and ground settlement of the constructed structure.

5) And performing experimental tunneling construction before penetrating the construction on the shield construction side to obtain necessary tunneling parameters such as shield propelling pressure, ground settlement and the like, and performing information construction.

6) Identifying and evaluating a danger source: the shield is downwards penetrated through a DN2200 regeneration pipe, a DN2400 draft pipe and a DN3200 sewage tunnel to be judged as a major hazard source. The shield is downward penetrated by DN1016 high-pressure gas pipeline (three-middle interval) as major hazard source. The shield side penetrates through the DN1400 water main pipe and the shops along the street to be judged as a major hazard source.

7. Monitoring purposes and items

The closure difference of settlement observation is executed according to the level II leveling limit difference in the urban rail transit engineering measurement Specification GB 50308-2008. The horizontal displacement monitoring is carried out according to the II-level technical requirements and the monitoring method in the urban rail transit engineering measurement Specification GB 50308-2008.

Monitoring the pipeline settlement: the monitoring object is a line in the influence range. Measuring point layout principle: 1) arranging a measuring point every 5-10 m above the pipeline in a main influence area of the shield, wherein the distance between important pipeline measuring points is 5-10 m and the distance between general pipeline measuring points is 5-10 m according to the attribute of the pipeline; 2) shielding the pipeline in the secondary influence area; and (4) arranging a measuring point every 20-30 m along the pipeline direction according to the attribute of the pipeline.

Monitoring frequency:

the engineering monitoring frequency is determined to meet the requirement of reflecting the important change process of the project measured by the monitored object without omitting the change moment. The monitoring frequency of the shield project needs to be determined by comprehensively considering the shield type, different construction stages of the shield and the underground project, the change of the surrounding environment and natural conditions and local experience. Under the condition of no data abnormity and accident symptoms, the field monitoring frequency after excavation can be determined according to the construction process. When one of the following conditions is met, the monitoring should be enhanced, and the monitoring frequency or the field inspection frequency should be properly increased:

(1) monitoring data reaching an alarm value;

(2) the monitoring data has larger variation or higher speed;

(3) the existence of unfavorable geological conditions not found in the survey;

(4) a shield and a large amount of accumulated water around the shield, long-time continuous rainfall and leakage of municipal pipelines occur;

(5) the ground load near the shield suddenly increases or exceeds the design limit value;

(6) sudden large settlement or severe cracking of the surrounding ground;

(7) sudden large settlement, uneven settlement or severe cracking of adjacent buildings (structures);

(8) and other abnormal conditions affecting the safety of the tunnel and the surrounding environment occur.

7.1 surface subsidence monitoring

The project monitoring aims to monitor the displacement of the soil around shield construction, know the stability of the soil and indirectly judge the safety condition of the enclosure structure.

Measurement form and working principle:

for monitoring the surface subsidence, a vertical displacement monitoring network is established by taking a No. 6 line first-stage engineering elevation system and a No. two stage engineering elevation system of the Chengdu subway as a reference through closing and attaching a leveling line. The control point is composed of a reference point and a working base point. In general, the reference point may utilize a measurement control point provided by a design unit. If the measurement control point provided by the design unit can not be used, the self-manufacturing can select a more stable position.

Measuring point layout principle and method: as shown in fig. 5.

The settlement monitoring points are arranged on the ground surface within the construction influence range according to the requirements in the design drawing, and the principle is as follows: the ground surface settlement monitoring points are buried in a mode of manual excavation or drilling tool hole forming, and are required to penetrate through a pavement structure layer. And a protective cover 4 is added at the measuring point, and the aperture is not less than 80 mm. The road and surface settlement monitoring measuring points are buried flatly, so that the passing of personnel and vehicles is not influenced, and meanwhile, the measuring points are stably filled with coarse sand 2, clear marks are made, and the protection is convenient.

The surface subsidence measuring point is buried underground by adopting a mode of manual excavation or drilling tool pore-forming, and the burying steps are as follows:

a. excavating holes with the diameter of about 130mm and the depth of about 1m on the hard earth surface by using a Luoyang shovel, and tamping the bottoms of the holes;

b. removing residue soil, and injecting a proper amount of clear water into the hole for curing;

c. a twisted steel bar mark point 3 with the length not less than 100cm is placed in the center of the hole, the surface of the filler is exposed by about 1-2 cm, the height of a measuring point is lower than the height of a road surface so as to avoid the influence of a travelling crane on the measuring point, and the measuring point is backfilled by coarse sand and tamped;

d. a steel protective cover 4 with the diameter not less than 110mm is arranged on the upper part;

e. maintaining for more than 15 days. The method enables the measuring points to directly reflect the changes of the soil layer 1 in an end-bearing mode.

The observation of the datum points and the working base points is observed according to the technical requirements of vertical displacement monitoring networks such as engineering measurement Specifications GB50026-2007 and the like. When the observation adopts a closed leveling route, only a single way of observation can be carried out, the reciprocating observation is carried out by adopting an attached leveling route form, and the adjustment is carried out by taking the number of height differences observed twice. And (3) observation sequence:

and (3) testing: back, front, back; and (3) return measurement: front, back and front;

the observation considerations are as follows:

① the level gauge and leveling rod should be checked before and after the project is started and finished, and the project should be checked regularly during the project to ensure the instrument is in good condition;

② observing to achieve three fixation, namely fixing personnel, fixing instruments and fixing measuring stations;

③ the storage position and mode of the recording file should be set correctly before observation, and the control tolerance parameters of the precision level are checked and set to ensure the compliance with the observation requirements;

④ should be observed under the condition of no air wave and clear scale;

⑤ the observation can be started when the temperature of the instrument is consistent with the outside temperature;

⑥ the number of stations for forward and backward measurement in each measurement section should be even, otherwise, the zero point difference of the scale should be added for correction;

⑦ when the direction changes from the forward direction to the backward direction, the two scales should be exchanged and the instrument should be reset;

⑧ when completing the closing or attaching route, the closing or attaching condition recorded electronically should be noted, the measurement can be completed after confirming the qualification, otherwise, the reason should be searched until the rework retesting is qualified.

7.2 line settlement monitoring, as shown in FIG. 7.

The underground pipeline settlement monitoring point is arranged on a pipeline influenced by construction, and the principle of measuring point arrangement is as follows:

① underground pipeline monitoring points are mainly arranged on gas pipes, water supply pipes, sewage pipes, large rainwater pipes and municipal pipelines in principle, and the relative position relationship between the underground pipelines and the engineering is considered when measuring points are arranged;

the ② measuring points are preferably arranged at nodes, corner points or parts sensitive to displacement changes of the pipelines of the pipeline, and the arrangement distance is 25 m.

③ according to the requirement of design drawing, the pipelines with special requirement are arranged at pipeline top points, and the pipelines without special requirement are arranged at corresponding earth surface monitoring points above the pipelines.

The underground pipeline settlement monitoring point burying method comprises the following steps:

① the underground pipeline with inspection well should open the well cover and directly arrange the measurement point on the pipeline or the pipeline carrier;

② the exposed pipeline is excavated for the pipeline without inspection well but with excavation condition, and the measuring points are directly distributed on the pipeline;

③ pipelines without inspection wells and excavation conditions can be buried at the corresponding earth surface to form indirect observation points.

When monitoring points are arranged on the pipeline, a water drill with the diameter larger than phi 120 can be adopted for the closed pipeline to drill the hardened ground layer into a steel pipe protection well 4, then a Luoyang shovel is used for digging a hole to the outer protective wall of the pipeline 1, the periphery between the deformed steel bar 5 and the soil layer 2 is filled with fine sand 3, and the steel bar is prevented from changing along with the change of the soil body. In order to avoid damage of vehicles to the measuring points, the placed steel bars 5 are 2cm lower than the road surface, the measuring points are protected by covering steel protection covers 6, and fine sand is filled at the measuring points. For open pipelines, the monitoring point support can be arranged on the pipeline or a pipeline buttress.

Monitoring the settlement of the underground pipeline: underground pipeline monitoring points are arranged on the pipeline, at positions corresponding to projects or on corresponding surface buried indirect observation points, and particularly, the arrangement distance is 25m at the nodes, corner points or parts sensitive to displacement change of the pipeline;

the monitoring method comprises the following steps: the underground pipeline settlement observation can be shared with the ground surface settlement level monitoring net, and underground pipeline settlement monitoring points are incorporated into the underground pipeline settlement observation net to form forms of closed circuits, attached circuits and the like. The settlement monitoring and observing method, the adopted instruments, the observing precision and the data and the processing of the underground pipelines are the same as the surface settlement monitoring. During the first observation, the same observation object is observed for three times, and then the average value is taken as an initial value.

8. Control reference and alarm value

The monitoring and early warning are one of the purposes of monitoring work and are important measures for preventing engineering accidents and ensuring the safety of engineering structures and surrounding environments. The monitoring control value and the early warning value are the precondition for implementing the monitoring work and are important bases for judging whether the engineering structure and the surrounding environment are in normal, abnormal and dangerous states during the monitoring period, so that the monitoring control value and the warning value are determined necessarily. The monitoring control value and the alarm value are commonly controlled by two indexes of a monitoring variable accumulated value and a change rate.

The monitoring control values and alarm values adopted in the project are as follows:

monitoring a feedback program: in order to ensure the truth, reliability and continuity of the measured data, the following quality assurance measures are specially made:

(1) the monitoring pair is closely matched with the supervision engineer to work, timely report conditions and problems to the supervision engineer and provide relevant practical and reliable data and records.

(2) The arrangement of the measuring points is reasonable, and the actual deformation and stress conditions of the structure in the construction process and the influence degree on the surrounding environment can be reflected.

(3) The test element and the monitoring instrument are qualified products of a regular manufacturer, the test element has a qualification certificate, and the monitoring instrument needs to be checked and calibrated regularly.

(4) The quality of the embedded measuring points can meet the design requirements. And the position is accurate, safe and stable, and a striking protection mark is set.

(5) The monitoring work is responsible for engineers who are engaged in the monitoring work for many years and have similar engineering monitoring experiences, and other members of the team are also engineers or testers who have the monitoring work experience, so that the relative fixation of monitoring personnel is ensured, and the continuity of data information is ensured.

(6) The monitoring data should be timely sorted and analyzed, and generally reported once per week under a general condition, and reported once per day under a special condition. The monitoring report includes the phase deformation value, deformation rate and accumulated value, and the settling tank curve, duration curve, etc. are drawn for necessary analysis and evaluation of the monitoring result.

(7) The detection data can be reported after field inspection and rechecking; if the monitored data is abnormal, the monitoring data is immediately retested, the monitoring instruments, the monitoring methods and the calculation process are checked, and after the data is confirmed to be correct, the data is immediately reported to a first party, a supervision and a unit supervisor so as to take measures.

(8) Each monitoring item must strictly comply with the corresponding test implementation rules in the monitoring process.

(9) The rainy season is the unfavorable condition of construction, and underground infiltration is more serious. Therefore, the normal monitoring frequency is ensured in rainy season, and the measuring frequency of weak links, main pipelines, buildings and other items is enhanced.

Monitoring report, handling and alarm elimination flow:

when the monitoring value of each monitoring project exceeds 70% of the control standard value determined by the design file, the specification and the regulation, the construction monitoring unit sends a pre-warning report to the relevant units and departments. And the monitoring is reinforced, and the deformation condition is mastered at any time until the deformation tends to be stable. After receiving the warning report reported by the monitoring unit, the construction unit should actively take corresponding technical measures to control the development of the deformation trend.

When the monitoring value reaches the control standard value, the construction monitoring unit sends an alarm report to the relevant units and departments, after receiving the alarm report sent by the monitoring unit, the construction unit stops construction, actively communicates with designers and premise supervision, organizes the discussion and analysis of reasons of the relevant departments, makes a processing scheme and corresponding measures, and implements the processing scheme and the corresponding measures in the shortest time to ensure the engineering safety. Meanwhile, the construction unit shall report the determined scheme, the taken measures, the treatment effect and the like to the construction command department in time.

The report content is as follows:

(1) summarizing field construction;

(2) an abnormal monitoring value: monitoring the change rate, the accumulated value, the change trend and the like of the variables, and carrying out engineering dangerous case early warning according to monitoring management level indexes;

(3) analyzing reasons of abnormal monitoring values;

(4) main conclusion, construction suggestions and the like.

Dangerous case warning process:

after monitoring, measuring and early warning, the construction unit timely disposes according to the requirements of the special meeting. And taking corresponding safety processing measures during the non-alarm period. After the monitored data are stable and meet the alarm-eliminating conditions, construction units propose alarm-eliminating applications (the total package unit signs the alarm-eliminating opinions for investment and financing projects), and units such as report supervision, third-party monitoring, construction and the like check, and alarm-eliminating is carried out after the participation parties agree. After the alarm eliminating process is completed, the supervision unit uploads an alarm eliminating application form to the monitoring platform in time, and the platform is eliminated for early warning.

9. Emergency rescue measures

Electric power tunnel emergency measures:

1) when the electric power tunnel monitoring deformation has abnormal conditions, the monitoring should be strengthened in time to master the deformation trend.

2) When the power tunnel deformation tends to deteriorate, the emergency plan should be started immediately.

3) And reporting to subway companies and property units, dispatching places and living committees, and assisting in evacuating nearby residents.

4) And immediately organizing to reinforce the power tunnel. And adopting grouting to reinforce the soil body within the range of 5.0m around the electric power tunnel, wherein the ground grouting material adopts pure cement paste, the grouting pressure is 0.2-0.4 MPa, and the soil body reinforcing depth is 5.0 m.

5) And grouting in the holes for reinforcement. Pure cement slurry is adopted. The grouting pressure is 0.2-0.4 MPa.

Emergency measures for abnormal rain and sewage pipes:

1) the deformation conditions of rain and sewage pipes are monitored in an enhanced manner, and monitoring data are reported to technical responsible persons and project responsible persons quickly;

2, according to the deformation data of the on-site monitoring pipeline, on the basis of analyzing shield tunneling parameters, soil output, geological survey data and related design data, a technical responsible person calls a brief technical conference to determine to adopt ground grouting and secondary grouting behind a tunnel inner pipe sheet;

and 3, immediately notifying a pipeline property right unit once a pipeline damage accident occurs, reporting the specific condition of pipeline damage, and assisting the pipeline property right unit to carry out emergency repair.

Emergency measures for gas pipeline accidents:

1) when abnormal conditions exist in the monitoring deformation of the gas pipeline, the monitoring is timely strengthened, and the deformation trend is mastered.

2 when the deformation of the gas pipeline tends to deteriorate, an emergency plan should be started immediately.

3 immediately reinforcing the gas pipeline. And adopting grouting to reinforce the soil body within the range of 5.0m around the pipeline, wherein the ground grouting material adopts pure cement paste, the grouting pressure is 0.2-0.4 MPa, and the soil body reinforcing depth is 8.0 m.

And 4, grouting in holes for reinforcement. Pure cement slurry is adopted. The grouting pressure is 0.2-0.4 MPa.

5, field operators on duty strengthen field inspection, judge whether gas leakage, combustion and explosion accidents occur or not by the following method, and immediately dial an emergency call and a fire alarm call 119 of a gas pipe network company after confirming the occurrence of the accidents.

Emergency measures for surface subsidence accidents:

1) the shield is constructed according to the construction organization design and the technology intersection.

2) In case when the surface subsidence appears, dredge the ground road immediately, avoid resident and vehicle pedestrian to be close to the collapse pit position, guarantee good rescue emergency passage.

3) And immediately organizing to carry out backfill treatment on the collapse pit, and preventing the collapse pit from expanding.

4) And construction monitoring is strengthened, and deformation tendency is concerned.

5) When the subsidence may endanger the safety of surrounding buildings, pipelines or residents' lives and properties, subway companies should be immediately reported and help the conductors and protect the power tunnels.

6) When casualties occur, people can immediately rescue the people from public security, fire fighting and other societies.

Claims

1. A construction method for a shield tunneling pipeline, comprising the following steps:

(1) Optimize the tunneling parameters, ground settlement control standards, and pipeline settlement control standards of the pipelines that pass through the danger source, and find out the relative relationship between the construction environment and the tunneling parameters. For the stratum and the composite stratum of the upper sand and gravel and the lower mudstone, the optimal settings of the tunneling parameters are:

The tunneling parameters of the full-section mudstone stratum shield under-passing or side-passing pipeline are:

The tunneling parameters of the composite stratum shield under/side penetration pipeline of the upper part of the pebble and the lower part of the mudstone are:

The dangerous sources are rainwater pipes, power pipelines, high-pressure gas pipes and sewage pipes;

(2) Reinforcing the dangerous source pipeline passing through;

(3) Monitoring of surface subsidence;

(4) Monitoring the settlement of underground pipelines;

(5) Set the monitoring control benchmark and alarm value.

2. The construction method of shield tunnel penetration pipeline according to claim 1, the shield tunnel penetration rainwater pipe, power pipeline pipeline reinforcement, comprising the following steps:

(1) Before the shield tunnel passes through the pipeline, stop the machine at the first 10m to check the machine condition, and open the warehouse to check the cutter to ensure continuous tunneling when the shield tunnel passes through the danger source;

(2) Control the excavation parameters: clarify the mileage of rainwater pipes and power pipes and their relationship with the position of the interval tunnels, control the excavation earth pressure fluctuation within the range of 0.1bar during the construction process, and use foam soft earth pressure;

(3) Ensure the improvement of the slag and control the slag output by increasing the foaming agent and the amount of water added; during the shield tunneling process, the unearthed volume is uniformly controlled according to the footage and earth pressure, and the unearthed volume and the grouting volume are matched at the same time;

(4) According to the surface settlement and excavation conditions, when the segment is pulled out of the 5-10 ring of the shield tail, a double-liquid grouting machine is used to reinforce the upper back of the segment by secondary grouting to fill the building gap behind the segment and shorten it. Simultaneous grouting slurry setting time; the formation is reinforced through reserved grouting holes in the segment, and the reinforcement form is supplemented by double-liquid slurry as the main single-liquid cement slurry. In-hole grouting reinforcement is carried out within m range;

(5) High-quality shield tail grease is used to improve the sealing effect and prevent the shield tail from leaking slurry;

(6) Monitor the stress and strain of the crossing section;

(7) When the interval tunnel passes through this section, additional grouting hole segments shall be used, and supplementary grouting shall be carried out to strengthen the stratum in time according to the monitoring situation.

(8) Strengthen monitoring and measurement to monitor the displacement and ground subsidence of power tunnels;

(9) Carry out test and trial excavation construction before the shield construction goes down the power tunnel to obtain the excavation parameters of the shield propulsion.

3. The construction method of the shield tunneling pipeline according to claim 1, the reinforcement of the shield tunneling sewage pipeline, comprising the following steps:

(1) Before the shield goes down the pipeline, stop the machine at the first 10m to check the machine condition, and open the warehouse to check the cutter to ensure that the shield continues to excavate when it passes through the danger source.

(2) Control the tunneling parameters of the shield: control the stratum loss rate within 2%, and the shield advancing earth pressure is not less than 0.8 times the theoretical water and soil pressure; after the shield passes, the grouting is performed in a timely manner, and the synchronous grouting amount and grouting pressure are controlled. , the unconfined uniaxial compressive strength should not be less than 1MPa; clarify the mileage of the drainage pipeline and the relationship with the location of the tunnel in the interval;

(3) Ensuring the improvement of the slag by increasing the amount of foaming agent and water, controlling the amount of slag, reducing the rotational speed of the cutterhead and the advancing speed to ensure that the shield passes at a uniform speed and appropriately increase the earth pressure;

(4) According to the surface settlement and excavation conditions, when the segment is pulled out of the 5-10 ring of the shield tail, a double-liquid grouting machine is used to reinforce the upper back of the segment by secondary grouting to fill the building gap behind the segment and shorten it. Synchronize the solidification time of the grouting slurry; strengthen the grouting measures in the cave, and strengthen the formation through reserved grouting holes in the segment. Influence; the length of grouting reinforcement in the left and right line holes is 30 meters; after the shield passes, it is decided whether to follow the grouting according to the results of monitoring and measurement. Reinforcement range: The reinforcement range of the forward penetration section is to expand 360° around the tunnel by 1.5m and carry out secondary grouting in the hole;

(6) Monitor the stress and strain of the crossing section;

(7) When the interval tunnel passes through this section, use additional grouting hole segments, and timely supplement grouting to strengthen the stratum according to the monitoring situation.

4. The construction method of the shield tunneling pipeline according to claim 1, wherein the shield tunneling and buried high-pressure gas pipeline pipeline reinforcement comprises the following steps:

(1) Strictly control the tunneling parameters of the shield, which is mainly reflected in the control of the formation loss rate within 2% and the shield driving pressure not less than 0.8 times the theoretical water and soil pressure. After the shield passes through, grouting shall be carried out in a timely manner, and attention shall be paid to controlling the amount of grouting and the grouting pressure. The unconfined uniaxial compressive strength shall not be less than 1MPa, and the mileage of the gas pipeline and the positional relationship with the tunnel in the interval shall be specified;

(2) Ensure the improvement effect of the slag by increasing the amount of foaming agent and water, and strictly control the amount of slag, reduce the rotational speed and propulsion speed of the cutter head to ensure uniform passage of the shield and appropriately increase the earth pressure;

(3) According to the ground subsidence and excavation conditions, when the segment is pulled out of the shield tail 5-10 rings, choose a suitable time to perform secondary grouting reinforcement with a double-liquid grouting machine behind the upper part of the segment, and fill the back of the segment. Building voids and shortening the solidification time of the synchronous grouting slurry; additional grouting holes are added on the segment to reinforce the left and right line holes with secondary grouting. The reinforcement length of the left and right lines is 10 meters, and the reinforcement range of the lower penetration section is the tunnel. The secondary grouting in the hole is carried out by expanding the surrounding 360° within a range of 1.5m;

(4) High-quality shield tail grease is used to improve the sealing effect and prevent the shield tail from leaking slurry;

(5) Monitor the stress and strain of the crossing section;

(6) When the interval tunnel passes through this section, use additional grouting hole segments, and timely supplement grouting to strengthen the stratum according to the monitoring situation.

5. The construction method of the shield tunneling pipeline according to claim 3, the reinforcement of the shield tunneling sewage pipeline on the side comprises the following steps: the construction of the shield tunneling of the sewage pipe adopts line adjustment, drainage, isolation or reinforcement, and through centralized drainage The submersible sewage pump is a pumping and drainage equipment, and the sewage is discharged through the submersible sewage pump after the sewage main pipe is blocked;

(1) Strictly control the tunneling parameters of the shield, which is mainly reflected in the control of the formation loss rate within 2% and the shield driving pressure not less than 0.8 times the theoretical water and soil pressure. After the shield passes through, the grouting shall be carried out in a timely manner, and attention shall be paid to the control of the synchronous grouting amount and the grouting pressure. The unconfined uniaxial compressive strength shall not be less than 1MPa.

(2) The ratio of cement slurry and grouting pressure parameters should be based on the principle of first test and then make, and the water-cement ratio should be 1:1; 6/cm/s.

(3) Additional grouting holes are added to the segment to reinforce the tunnel by secondary grouting;

(4) Strengthen monitoring and measurement. Shield tunnel implements information construction through the whole process, and closely monitors the displacement and land subsidence of structures;

(5) Carry out experimental excavation construction before the shield construction side penetrates the building to obtain the shield excavation parameters.

6. according to the described shield tunneling pipeline construction method described in claim 1, described to surface settlement monitoring, comprises the following steps:

Layout of ground settlement monitoring points: Drill holes in soil layer 2, and set threaded steel bar marking points 5 in the holes. The length of said threaded steel bar marking points is greater than 90cm. Fill coarse sand 3 between the threaded steel bars and the soil layer, and drill holes There is a protective cover 6 above; the drilled hole penetrates the pavement structure layer, the diameter of the drilled hole is about 80-130mm, the depth is about 1m, the length of the threaded steel bar is greater than 100cm as the mark point, and the coarse sand surface of the filler is exposed 1-2cm, steel protection Cover diameter is greater than 110mm; maintenance for more than 15 days;

When the observation adopts a closed leveling route, one-way observation is performed, and a round-trip observation is performed in the form of an attached leveling route, and the median of the height difference between the two observations is used for adjustment; back, back, front.

7. The construction method of the shield tunneling pipeline according to claim 1, the monitoring of the settlement of the underground pipeline comprises the following steps: the underground pipeline monitoring point is arranged on the pipeline, the position corresponding to the project or the corresponding surface buried indirect At the observation point, specifically at the node, corner point of the pipeline, or the position sensitive to displacement changes, the layout spacing is 25m;

Burying method of underground pipeline settlement monitoring point: For closed pipelines, use water drills to drill through the ground hardened layer, dig holes to the outer protective wall of pipeline 1, put in the reinforcement 5 and fill it with fine sand 3, and the position of the reinforcement 5 should be lower than the surface covered with steel. The protective cover 5 protects the measuring point, and at the same time fills the measuring point with fine sand 3; for the open pipeline, the monitoring point support is made on the pipeline or pipeline pier.

8. according to the described shield tunneling pipeline construction method described in claim 1, described setting monitoring control reference and alarm value comprises the following steps:

Two control indicators, cumulative value and rate of change of monitoring variables, are used. The parameters are:

9. The described shield tunneling pipeline construction method according to claim 1, further comprising the steps of: monitoring feedback, reporting, disposal and fire-fighting emergency rescue measures, and power tunnel emergency measures:

(1) Reinforcement of power tunnels: grouting is used to reinforce the soil within 5.0m around the power tunnel. The ground grouting material is pure cement slurry, the grouting pressure is 0.2-0.4MPa, and the soil reinforcement depth is 5.0m:

Grouting reinforcement in the power tunnel hole: pure cement slurry is used. Grouting pressure 0.2～0.4MPa;

(2) Emergency measures for abnormal rain and sewage pipes: take ground grouting and secondary grouting behind the segment in the tunnel;

(3) Emergency measures for gas pipeline accidents:

Reinforce the gas pipeline: use grouting to reinforce the soil within a range of 5.0m around the pipeline, the ground grouting material is pure cement slurry, the grouting pressure is 0.2-0.4MPa, and the soil reinforcement depth is 8.0m;

In-hole grouting reinforcement: pure cement slurry is used, and the grouting pressure is 0.2-0.4MPa.

10. The construction method of the shield tunneling pipeline according to claim 5, further comprising the steps of: observing,

①The used level and level should be inspected before and after the project, and should be inspected regularly during the project to ensure that the instrument is in good condition;

②The observation should be fixed in three ways, namely, fixed personnel, fixed instruments, and fixed stations;

③ Before the observation, the storage location and method of the recording file should be correctly set, and the various control tolerance parameters of the precision level should be checked and set to ensure that the observation requirements are met;

④The observation should be carried out under the condition of no air wave and to ensure that the scale of the scale is clear;

⑤The observation can only be started when the temperature of the instrument is consistent with the outside temperature;

⑥ The number of measuring stations to and from each measuring section should be an even number, otherwise the zero point difference correction of the scale should be added;

⑦ When changing from the forward measurement to the backward measurement, the two rulers should exchange positions, and the instrument should be rearranged;

⑧ When completing the closing or attachment route, attention should be paid to the closing or attachment difference of the electronic record, and the measurement work can be completed only after the confirmation is passed.