JP2015021322A - Tunnel construction method and tunnel structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tunnel construction method capable of reducing rigidity of a tunnel structure required for the amount of loaded earth for backfilling, and a tunnel structure.SOLUTION: On a construction surface GL, an outside lining frame 30 is installed outside a plurality of installed supports 20 that are arranged at predetermined intervals along an axial direction T of a tunnel, and the supports 20 and an upper part of the outside lining frame 30 are constructed by being backfilled with (leanly-mixed) lean-mix concrete 120 with light cement loading.

Description

  For example, the present invention relates to a tunnel construction method and a tunnel structure in which an upper part of a tunnel structure installed at a tunnel construction site is backfilled to construct a tunnel.

Conventionally, various construction methods and structures have been proposed for tunnels according to the environment and conditions of the tunnel construction site, and safe and cost-effective structures and construction methods have been adopted.
In Patent Document 1, a method for constructing a ceiling part of a tunnel structure so as to be excavated in advance and supported by surrounding ground is proposed as an example of a tunnel construction method. Yes. For example, in the case of a construction method in which the tunnel structure is excavated to the bottom of the tunnel structure and then backfilled with backfill earth and sand, depending on the construction environment, earth retaining to the surrounding ground is required, which increases construction days and construction costs. Therefore, it is said that it can be constructed safely and inexpensively compared to such a construction method.

  However, in the tunnel construction method in Patent Document 1, since the upper part of the ceiling part of the tunnel structure is backfilled with backfill earth and sand, the tunnel structure is constructed by excavating the lower part of the ceiling part. It is necessary to support the earth pressure by the backfilled soil only by the ceiling portion, and therefore, the ceiling portion needs to have high rigidity, and there is a problem that the thickness of the ceiling portion is increased.

  In the first place, in the case of a construction method in which a tunnel structure as shown in Patent Document 1 is constructed and then the upper part is backfilled with backfill earth and sand, the amount of backfill soil to be backfilled with backfill earth and sand, that is, the whole soil for the backfill height. Since the pressure acts on the tunnel structure, depending on the construction environment, for example, in a tunnel structure constructed by excavating a natural mountain such as a mountain tunnel (hereinafter referred to as an excavation tunnel), the earth covering is about the same as the backfill height. Compared to the excavation tunnel having the above, for example, there is a possibility that a tunnel structure using a high-rigidity member having a thick sprayed concrete thickness or member thickness, that is, a tunnel structure requiring high rigidity.

JP 11-323974 A

  Therefore, an object of the present invention is to provide a tunnel construction method and a tunnel structure that can reduce the rigidity of the tunnel structure required for the amount of backfilled soil to be mounted.

  The present invention is a tunnel construction method and a tunnel structure in which an upper part of a tunnel structure installed at a tunnel construction site is backfilled to construct a tunnel, and after constructing at least an upper half part of the tunnel structure, The upper part of the upper half portion is constructed by backfilling with a poorly mixed backfilling material in which a solidifying material is blended with a poor blending.

  The above-mentioned tunnel structure is a concept including a tunnel structure covered with a lining material such as cast-in-place concrete, a tunnel structure in which a closed cross-section structure such as a segment or a concrete BOX is assembled. Yes, including tunnel structures having various cross sections such as arch (horse-shoe), circle, ellipse, and rectangle, and may be a multiple tunnel.

The poor compounding backfill material in which the above-mentioned solidifying material is blended with poor blending is, for example, fluidized treated soil which is a stable treated soil obtained by kneading and fluidizing the solidified material and water to the soil generated at the construction site. , Solidified soil and the like. The solidified material is not only cement-based solidified material but also lime-based solidified material such as slaked lime and quicklime, liquid solidified material, etc., which is an appropriate solidified material according to the application, construction conditions, target soil quality, etc. be able to.
More specifically, for example, it is composed of a small amount of solidification material (cement) necessary for concrete having general strength, that is, composed of concrete in which the solidification material (cement) is poorly mixed. It is a backfill material.

According to the present invention, the rigidity of the tunnel structure required for the amount of backfill soil to be mounted can be reduced.
Specifically, the upper portion of the tunnel structure is backfilled with a poorly mixed backfill material in which the solidifying material is blended with a poor blend, so that the poor blended backfill material hardens and becomes self-supporting, so it does not harden normally. Compared with the case where the same amount of soil is backfilled with backfill earth and sand, the overhead load acting on the tunnel structure can be reduced.

  Therefore, the strength of the structural member constituting the tunnel structure, that is, the rigidity of the tunnel structure can be reduced. Therefore, a tunnel structure can be constructed economically.

In addition, as a backfill soil for backfilling the upper part of the tunnel, the use of a poorly mixed backfill material that contains a solidified material with a poor composition hardens without being fully compacted. Even in the case of construction, the workability is improved and it can be reliably backfilled. Furthermore, for example, it can be realized at a lower cost than in the case of placing concrete in order to obtain self-supporting property after curing.
Thus, according to the present invention, the tunnel structure itself and backfilling can be performed inexpensively and reliably, and an economical tunnel structure can be realized.

  As an aspect of the present invention, the tunnel structure is provided with arch-shaped supporters protruding upward at a predetermined interval in the tunnel axial direction, and at least the inner upper half portion of the tunnel cross section is covered with a covering material. In addition, the structure is constructed by forming an invert in the lower part of the tunnel cross section, and a supporting process for installing the support work at the tunnel construction location, and an outer lining frame is installed outside the installed support work. The outer lining frame installation step, the inner beam installation step of installing an inner beam so as to close the cross section of the supporting work between the lower ends of the supporting works, and the upper part of the outer lining frame, A backfilling process for backfilling with a poor compounding backfill material, an inner beam removing process for removing the inner beam after the poor compounding backfill material is cured, and an invert process for forming an invert at the lower portion of the tunnel cross section, In this order Door can be.

The lining material and the invert may be a lining material made of an appropriate material such as cast-in-place concrete, a concrete processed product, steel, or resin.
The outer lining frame can be made of a material having a predetermined strength such as a keystone plate or a steel mold having an appropriate thickness.

By this invention, the tunnel structure which can reduce the rigidity required with respect to the amount of the backfill soil to be mounted can be efficiently constructed.
Specifically, upwardly projecting arch-shaped supporters are installed at predetermined intervals in the tunnel axis direction, and at least the inner upper half of the tunnel cross section is covered with a covering material, and the lower part of the tunnel cross section is inverted. In the tunnel construction location, the support process of installing the support work, and the outer cover frame installation process of installing an outer cover frame outside the support work installed, An inner beam installation step of installing an inner beam between the lower ends of the support works so that the cross section of the support work is closed, and an upper portion of the outer lining frame are buried with the poor compounding backfill material. It is mounted by performing a returning step, an inner beam removing step of removing the inner beam after hardening of the poor compounded backfill material, and an invert step of forming an invert at a lower portion of the tunnel cross section in this order. The amount of backfill soil The tunnel structure which can reduce the rigidity required to efficiently can be constructed economically.

  In the above-mentioned support process, or after the support process, a sprayer or a circular formwork is installed between the supporters in the tunnel axis direction with a spray material of an appropriate material such as mortar or resin. Then, a concrete placing work for placing concrete may be performed.

  Further, as an aspect of the present invention, when the tunnel cross section is measured and the displacement of each step in the backfilling step, the inner beam removing step, and the inverting step is within a preset management reference value, the next step is performed. It can be carried out.

  To measure the tunnel cross section mentioned above, measure the measurement points set in the tunnel structure with a transit measuring instrument, or automatically with the automatic tracking type transit measuring instrument, and the relative distance between the measuring points on the section. It is a concept including measuring with a measuring instrument.

  The management reference value set in advance is obtained by modeling the tunnel structure to be constructed, calculating the amount of displacement in each process, for example, by analysis such as dynamic analysis, and converting the calculated amount of displacement into the amount of displacement in the previous process. The management value can be set based on the accumulated amount, that is, the displacement amount from the initial shape.

According to the present invention, a tunnel structure can be constructed more safely.
More specifically, if the next step is performed before the displacement due to earth pressure acting on the tunnel structure under construction converges, unintended unnecessary stress is generated on the member to be constructed in the next step. Further, when the measurement result greatly exceeds the preset management reference value, an unintended pressure is acting on the tunnel structure being constructed. On the other hand, in addition to measuring the tunnel cross-section, if the displacement of each step in the backfilling step, the inner beam removal step, and the invert step is within a preset management reference value, to perform the next step, Because it is possible to build a tunnel structure while confirming that unintended unnecessary stress does not occur in the members to be constructed in the next process and that unintended pressure is not acting on the tunnel structure being built, It can be constructed safely.

Moreover, as an aspect of the present invention, in the backfilling step, the upper portion of the poor blend backfilling material backfilled can be backfilled with backfill earth and sand.
The poor blended backfill that has been backfilled at a height capable of supporting the backfilled soil so that the pressure of the backfilled sand that is mounted on the tunnel structure does not act on the upper part of the above-mentioned backfilled poor blended backfill material. It can be the top of the material.
The backfilling earth and sand can be high-quality soil such as mountain sand and true sand, or improved soil obtained by improving excavated earth and sand, as well as crushed stone, asphalt or roadbed material.

According to the present invention, it is possible to construct the upper part of the tunnel structure at a lower cost as compared with the case of backfilling with the poor blending backfill material.
In detail, in general, the earth pressure of the entire earth covering acts on the tunnel structure with a small earth covering, but after the poor compounding backfill material that has filled up the predetermined height of the upper part is cured, Even if the upper part of the poor compounded backfill material that has been backfilled is backfilled with backfill earth and sand, the earth pressure due to the backfilled sand that has been backfilled in the tunnel structure does not act, so cheap backfill earth and sand can be used. By backfilling the upper portion of the poor blended backfill material, a tunnel structure capable of reducing the rigidity required for the amount of backfilled soil to be mounted can be efficiently and more economically constructed.

In addition, as an aspect of the present invention, the tunnel construction site can be used as a pit of an excavation tunnel constructed by excavation, and a gate work for constructing a tunnel can be performed.
Normally, the tunnel head is constructed with light for the excavation tunnel where only a certain height of earth pressure called so-called loose earth pressure acts. Even with a wellhead part that often requires a tunnel structure, the wellhead part in the excavation tunnel can be made a structure that can reduce rigidity by the above-described structure and construction method. Can be built.

Moreover, as an aspect of the present invention, the tunnel construction location can be a traffic road intersection where a traffic path through which a passing body passes is filled.
The passing body can be a passing vehicle such as an automobile or a train, or a passerby.

  According to the present invention, for example, compared to a case where everything is backfilled with backfill earth and sand, there is no risk of problems such as consolidation settlement caused by aged consolidation, and a highly safe passage can be configured.

  ADVANTAGE OF THE INVENTION According to this invention, the construction method and tunnel structure of a tunnel which can reduce the rigidity of the tunnel structure required with respect to the amount of backfill soil to be mounted can be provided.

The schematic perspective view of an intersection tunnel. The cross-sectional view of the wellhead part of the crossing tunnel. The longitudinal cross-sectional view of the wellhead part of an intersection tunnel. The flowchart of the construction method of an intersection tunnel. Explanatory drawing by the front view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel. Explanatory drawing by the front view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel. Explanatory drawing by the front view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel. Explanatory drawing by the front view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel. Explanatory drawing by the front view of the construction method of an intersection tunnel. Explanatory drawing by the schematic perspective view of the construction method of an intersection tunnel.

An embodiment of the present invention will be described below with reference to the drawings.
First, an intersection tunnel 1 having an intersection passage 300 in a direction intersecting the tunnel axis direction T at the top will be described with reference to FIGS.

  1 shows a schematic perspective view of the crossing tunnel 1, FIG. 2 shows a cross-sectional view of the wellhead part 100 of the crossing tunnel 1, and FIG. 3 shows a longitudinal section near the center in the width direction of the wellhead part 100 of the crossing tunnel 1. FIG. 4 shows a flowchart of a method for constructing the intersection tunnel 1.

  5, 8, 10, 12, and 14 are explanatory views of the construction method of the intersection tunnel 1, and FIGS. 6, 7, 9, 11, 13, and 15 are schematic perspective views of the construction method of the intersection tunnel 1. FIG.

  Specifically, FIG. 5 (a) shows a front view of the cut work, FIG. 5 (b) shows a front view after completion of the concrete spraying work, and FIG. 6 (a) shows a schematic perspective view of the cut work. Fig. 6 (b) shows a schematic perspective view of the support construction installation work, Fig. 7 (a) shows a schematic perspective view of the outer lining frame installation work, and Fig. 7 (b) shows a concrete spraying work. The schematic perspective view of is shown.

  8A shows a front view of the inner beam installation work and the measurement preparation work, FIG. 8B shows a front view of the gate work, and FIG. 9A shows an inner beam installation work and A schematic perspective view of the measurement preparation work is shown, and FIG. 9B shows a schematic perspective view of the gate work.

  Moreover, Fig.10 (a) shows the front view about a poor mixing concrete backfill, FIG.10 (b) shows the front view about a roadbed backfilling, FIG.11 (a) is a poor mixing concrete backfill. The schematic perspective view about a construction is shown, and Drawing 11 (b) shows the schematic perspective view about a roadbed backfilling construction.

12A shows a front view of the inner beam removal work, FIG. 12B shows a front view of the invert work, and FIG. 13A shows a schematic perspective view of the inner beam removal work. FIG. 13B shows a schematic perspective view of the invert process.
14 (a) shows a front view of the lining, FIG. 14 (b) shows a front view of the road builder, FIG. 15 (a) shows a schematic perspective view of the lining, and FIG. 15 (b) shows a schematic perspective view of the road installation work.

The crossing tunnel 1 described in detail below is a mountain tunnel having an arched cross section for excavating the natural ground 200, and a passage 310 is formed in the tunnel interior T.
In FIGS. 1 to 3 and FIGS. 5 to 15, the natural ground 200 is cut and illustrated with the pit portion 100 serving as the end of the crossing tunnel 1 as a center. The tunnel structure has a predetermined length.

  Moreover, the construction method of the main body of the crossing tunnel 1 is not limited. For example, the natural ground 200 is excavated by NATM or the like, a supporting work is installed, and the inner spray is applied and then the lining is performed to obtain a predetermined cross section. You just need to build a tunnel.

  The wellhead portion 100 of the crossing tunnel 1 constructed in this way cuts a natural ground 200 that is the end of the crossing tunnel 1, and constructs a tunnel structure having the same internal cross section as the main part of the crossing tunnel 1. At the top, a crossing passage 300 is constructed in the direction intersecting the tunnel axis direction T. That is, the wellhead part 100 is constructed by light work.

  Specifically, the outer lining frame 30 is installed outside the support arch 20 having the same arch shape as the main body of the crossing tunnel 1, the sprayed concrete 40 is sprayed inside the outer lining frame 30, and the inside is covered with the lining material. 50 is lined and constructed. Further, a substantially arc-shaped invert 60 is constructed downwardly between the lower portions of the support works 20 in the cross-sectional direction of the intersection tunnel 1, and a passage 310 by the road body 70 is constructed above the invert 60.

Furthermore, a pit 110 is constructed at the end of the wellhead portion 100, and a predetermined height at the top of the outer lining frame 30 is backfilled with the poor blended concrete 120, and the top is buried with the roadbed material 130. Returning, the crossing road 300 is constructed on the upper surface.
The support 20 is configured by bending H-shaped steel into an arch shape, and the outer lining frame 30 is configured by bending a keystone plate according to the shape of the support 20.

The poor blended concrete 120 is composed of poor blended concrete having a predetermined strength. However, as long as it has a predetermined strength, the poor blended concrete 120 may be composed of fluidized soil obtained by treating excavated soil with cement.
More specifically, the amount of cement required for unreinforced concrete having a strength of 1600 kN / m ² is usually about 160 kg / m ³ , but poor blended concrete 120 has a required strength of 1000 kN / m ² , The amount of cement added is about 86 kg / m ³ . As described above, the poorly-mixed concrete 120 is a cement with a cement addition amount that is small compared to the cement addition amount for concrete having general strength, that is, a cement with poor cement content. The strength of the poor blended concrete 120 can be obtained by a uniaxial compression test or a cone test, and a cement addition amount that expresses a predetermined strength necessary as a backfill material may be obtained.
The roadbed material 130 can be a high-quality soil such as mountain sand or pure sand, or a backfill material such as improved soil obtained by improving excavated soil, or a roadbed material such as crushed stone.

A method for constructing the wellhead 100 of the crossing tunnel 1 constructed in such a configuration will be described with reference to the flowchart shown in FIG.
First, the management reference value of each process mentioned later is set (step s1). Specifically, the wellhead 100 is modeled in each process of a roadbed backfill (step s10), inner beam removal (step s12), and invert (step s14), which will be described later. The displacement amount is calculated by dynamic analysis, and the calculated displacement amount is accumulated, that is, the management reference value is set based on the displacement amount in the process with respect to the initial shape. The management reference value setting step (step s1) may be performed before the roadbed backfilling step (step s10) described later, and is not necessarily performed first.

  As an implementation work for constructing the wellhead portion 100 of the crossing tunnel 1, first, as shown in FIG. 6A, the ground 200 is cut so that the support work 20 can be installed, and the construction surface GL is formed (step) As shown in s2), FIG. 5 (b), and FIG. 6 (b), the support 20 in which the H-shaped steel is formed in an arch shape is installed on the construction surface GL (step s3).

  At this time, a plurality of support works 20 are arranged at predetermined intervals along the tunnel axis direction T, and the support works between the support works 20 are connected by a tie rod 21 to be integrated. A plurality of tie rods 21 are arranged along the arch shape, and are arranged so as to be staggered so that the arch-shaped cross-sectional positions do not continue in the tunnel axis direction T between the support works adjacent to each other in the tunnel axis direction T. doing.

  Subsequently, as shown in FIGS. 5 (a) and 7 (a). An outer lining frame 30 composed of a keystone plate is installed outside the supporting structures 20 arranged at predetermined intervals along the tunnel axis direction T (step s4), and the supporting structure inside the outer lining frame 30 is also provided. The work space is sprayed with sprayed concrete 40 to cover the work (see step s5, FIG. 7 (b)).

  As shown in FIGS. 8 (a) and 9 (a) in this state in which no overload is acting on the support 20 and the shotcrete 40 constituting the schematic cross section of the wellhead portion 100 in this way. Then, the inner beam 22 is installed so as to stretch the inner sides of the lower part of the support 20 formed in an arch shape (step s6).

  At this time, the inner beam 22 is installed so as to stretch the inner sides of the lower part of the support 20 formed in an arch shape so as to widen the foot of the arch shape so as to have a predetermined cross-sectional shape due to the applied load. To do.

  And the measuring point 23 used as a measuring point is installed with respect to the support work 20 in which the inner beam 22 was installed, and an initial shape is measured (step s7). In this embodiment, the measurement point 23 set in the support work 20 is measured by a measurement device such as a transit (not shown). However, a measurement device that measures the relative distance between the measurement points 23 is installed and measured. May be. Further, the displacement of the measurement point 23 may be measured by an automatic tracking type transit or the like.

After completion of the initial measurement, as shown in FIGS. 8 (b) and 9 (b), in order to function as a toe wall on the end side in the tunnel axial direction T when the upper portion of the support work 20 is backfilled, The tunnel 110 is constructed at the end of the tunnel opening 100 in the tunnel axial direction T (step s8). The pit 110 is constructed by assembling a formwork and placing concrete at the end of the pit portion 100 in the tunnel axial direction T.
In addition, after construction of the pit 110, the measurement point 23 may be installed in the support work 20, and an initial shape may be measured.

  After the completion of the construction of the tunnel 110, as shown in FIGS. 10 (a) and 11 (a), backfilling to a predetermined height from the upper side of the support work 20 and the outer lining frame 30 (step s9). ) After the poor blended concrete 120 is cured, as shown in FIGS. 10B and 11B, the upper portion of the poor blended concrete 120 is backfilled with the roadbed material 130 (step s10), and the upper portion of the support work 20 Complete the backfill. At this time, due to the backfilling of the poor blended concrete 120, the support work 20 on which the loading load acts is deformed.

  After completion of the backfilling, the measurement point 23 set in step s7 is measured, and the converged measurement result, that is, the deformation amount of the support 20 is the management reference value when the backfilling is completed among the management reference values set in step s1. If it is within the position, the process proceeds to the next process described later (step s11). If the converged measurement result exceeds the control reference value in each process in this process or the control reference value check process described later, the current process will not proceed to the next process and separate measures will be taken for the subsequent processes. To consider.

  In step s11, when it is confirmed that the measurement result at the time of completion of the backfilling is within the control reference value, that is, when the deformation amount of the support 20 is equal to or less than the assumed deformation, the upper load acting on the support 20 is calculated. Since it can be determined that the support beam 20 provided with the inner beam 22 is sufficiently supported, the inner beam 22 installed at the lower portion of the support beam 20 is removed (step s12).

  By removing the inner beam 22, the upper load is supported only by the arch action of the support work 20, that is, by removing the inner beam 22, the strength of the support work 20 in the tunnel cross-section direction is reduced. The work 20 is deformed.

  The amount of deformation of the supporting work 20 that is deformed by removing the inner beam 22, that is, the amount of deformation of the supporting work 20 that is obtained by removing the inner beam 22 to the amount of deformation of the supporting structure 20 so far. Is measured using the measurement point 23, and if the converged measurement result is within the management reference position at the time of completion of the inner beam removal among the management reference values set in step s1, the following will be described later. The process proceeds to step s13.

  In step s13, when it can be confirmed that the measurement result at the time of removing the inner beam is within the control reference value, the loading load acting on the support beam 20 can be sufficiently supported by the support beam 20 from which the inner beam 22 has been removed. Therefore, the invert 60 is installed in the lower part of the support work 20 (step s14).

  Specifically, as shown in FIGS. 12 (a) and 13 (a), a lower construction surface GL of the support work 20 from which the inner beam 22 has been removed is dug down to a predetermined depth, and the lower end of the support work 20 is placed at the dug position. The invert 60 is installed by placing concrete so as to straddle each other.

  After the installation of the invert 60 is completed, that is, after the concrete forming the invert 60 is cured, the measurement point 23 is measured, and the converged measurement result is the management standard at the time of completion of the invert work among the management standard values set in step s1. If it is within the position, the process proceeds to the next process described later (step s15).

  In step s15, when it can be confirmed that the measurement result at the completion of the invert work is within the control reference value, it can be determined that the support work 20 in which the invert is installed is sufficiently supported. As shown to 15 (a), the inner side of the support work 20 and the shotcrete 40 is covered with the covering material 50 (step s16). Further, as shown in FIGS. 14 (b) and 15 (b), the road body 70 is installed on the upper part of the invert 60 (step s17), the passage 310 is constructed, and the construction of the wellhead 100 is completed. To do.

  Note that the crossing road 300 may be constructed after the completion of the construction of the wellhead part 100 or may be constructed in parallel with the construction of the wellhead part 100 as long as it is backfilled with the roadbed material 130 in step s10. Good.

  The wellhead portion 100 constructed by such a construction method is constructed by backfilling the upper portion with the poor blended concrete 120 in which the solidifying material is blended with poor blending, and therefore the wellhead portion 100 required for the amount of backfilled soil to be mounted. The rigidity of can be reduced.

Specifically, since the poor blended concrete 120 hardens and becomes self-supporting when the upper portion of the wellhead 100 is backfilled with the poor blended concrete 120 in which the solidifying material is blended in the poor blend, a normal roadbed that does not cure. Compared with the case where the same amount of soil is backfilled with the material 130, the overload acting on the wellhead 100 can be reduced.
Therefore, the strength of the structural member constituting the wellhead portion 100, that is, the rigidity of the wellhead portion 100 can be reduced. Therefore, the wellhead 100 can be constructed economically.

In addition, in the case of narrow construction where compaction is difficult to construct because it is hardened without compaction by using the poor blended concrete 120 blended with poor blending material as the backfill soil to refill the upper part of the tunnel Even so, the workability is improved and it can be reliably backfilled. Furthermore, for example, it can be realized at a lower cost than in the case of placing concrete in order to obtain self-supporting property after curing.
As described above, according to the present invention, the wellhead portion 100 itself and backfilling can be performed inexpensively and reliably, and an economical wellhead portion 100 can be realized.

  Further, an upwardly projecting arch-shaped support 20 is installed at a predetermined interval in the tunnel axis direction T, and the inside of the cross section is covered with a covering material 50, and an invert 60 is formed at the lower part of the tunnel cross section. Supporting step (step s3) of installing the support 20 on the construction surface GL of the wellhead portion 100 to be constructed, and an outer lining frame installation step of installing the outer lining frame 30 on the outside of the installed supporting craft ( Step s4), the inner beam installation step (step s6) for installing the inner beam 22 so as to close the cross section of the support 20 between the lower ends of the support 20, and the upper part of the outer lining frame 30 A backfilling process (step s9) for backfilling with the poor blended concrete 120, an inner beam removing process (step s12) for removing the inner beam 22 after the poor blended concrete 120 is cured, and an invert 60 is formed at the lower portion of the tunnel cross section. And invert process (step s14) which, by performing in that order, it is possible to construct a wellhead portion 100 which can reduce the rigidity required against backfill soil amount of overburden efficiently.

  Moreover, while measuring a tunnel cross section using the measuring point 23, the displacement of each process in a backfill process (step s9), an inner beam removal process (step s12), and an invert process (step s14) was set beforehand. When it is within the reference value, the next step is performed, and thus the wellhead 100 can be constructed more safely.

  More specifically, if the next step is performed before the displacement due to earth pressure acting on the wellhead 100 under construction converges, unintended unnecessary stress is generated on the member to be constructed in the next step. Further, when the measurement result greatly exceeds the preset management reference value, an unintended pressure is acting on the wellhead portion 100 being constructed. On the other hand, while measuring the tunnel cross section, the displacement of each step in the backfilling step (step s9), the inner beam removing step (step s12), and the inverting step (step s14) is within a preset management reference value. In some cases, since the next step is performed, unintentional unnecessary stress is not generated in the member to be constructed in the next step, and it is confirmed that unintended pressure is not acting on the wellhead portion 100 being constructed. Since the wellhead 100 can be constructed, it can be constructed safely.

  Furthermore, in the backfilling step (step s9), the upper portion of the poor blended concrete 120 that has been backfilled is backfilled with the roadbed material 130, so that all the upper part from the wellhead portion 100 is backfilled with the poor blended concrete 120. And can be constructed at low cost.

  More specifically, in general, the earth pressure of the entire earth covering acts on the well opening portion 100 with a small earth covering, but after the poor blended concrete 120 that has filled up the predetermined height of the upper part is hardened, it is refilled. Even if the upper portion of the poor blended concrete 120 is backfilled with the roadbed material 130, the earth pressure due to the roadbed material 130 backfilled in the wellhead portion 100 does not act. By backfilling the upper part of the blended concrete 120, the wellhead 100 that can reduce the rigidity required for the amount of backfilled soil can be efficiently and more economically constructed.

  Moreover, the wellhead portion 100 where the entire earth pressure is applied to the excavation tunnel, which is constructed with light, is usually higher than the excavation tunnel. Although a rigid tunnel structure is often required, the construction method described above can provide a structure that can reduce rigidity, and a more economical tunnel structure can be constructed.

  Furthermore, since the tunnel construction place is the crossing passage 300 in which the passage through which the vehicle passes through is refilled, for example, as compared with the case where everything is backfilled with the roadbed material 130, Therefore, there is no risk of problems such as consolidation settlement caused by compact consolidation, and a highly safe passage can be configured.

In the correspondence between the configuration of the present invention and the above-described embodiment, the tunnel structure and the wellhead correspond to the wellhead portion 100,
Similarly,
The tunnel construction point corresponds to the wellhead part 100 of the crossing tunnel 1,
The poor blend backfill material corresponds to the poor blend concrete 120,
The support process corresponds to step s3 and step s4,
The inner beam installation process corresponds to step s6,
The backfill process corresponds to step s9,
The inner beam removal process corresponds to step s12,
The invert process corresponds to step s14,
The backfill earth and sand correspond to the roadbed material 130,
The excavation tunnel corresponds to the body of the crossing tunnel 1,
The tunnel worker corresponds to step s8,
The crossing part of the road corresponds to the crossing road 300,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

  For example, the above-described wellhead portion 100 has a plurality of supporters 20 arranged at predetermined intervals in the tunnel axis direction T, and the inside of the cross section is covered with a covering material 50 such as cast-in-place concrete. A closed cross-section structure such as the above may be assembled. Further, the lining material 50 and the invert 60 may be made of an appropriate material such as a cast-in-place concrete, a steel product, a resin, or a resin. The support 20 is not limited to an arch (horse-shoe), but may have various cross sections such as a circle, an ellipse, and a rectangle. Furthermore, a multiple tunnel structure may be used.

  In addition, the solidification material mix | blended in order to comprise the poor mixing | blending concrete 120 is not only a cement-type solidification material but lime-type solidification materials, such as slaked lime and quicklime, and a liquid solidification material, use, construction conditions, or object. It can be set as an appropriate solidifying material according to the soil quality.

DESCRIPTION OF SYMBOLS 1 ... Crossing tunnel 20 ... Supporting work 22 ... Inner beam 30 ... Outer lining frame 50 ... Covering material 60 ... Invert 100 ... Wellhead part 110 ... Tunnel 120 ... Poor compounding concrete 300 ... Crossing road T ... Tunnel axial direction

Claims (12)

A tunnel construction method in which a tunnel is constructed by refilling the upper part of a tunnel structure installed at a tunnel construction site,
After building at least the upper half of the tunnel structure,
A tunnel construction method in which the upper part of the upper half is backfilled with a poorly blended poorly blended backfill material. The tunnel structure,
An upward arch-shaped support is installed at a predetermined interval in the tunnel axis direction, and at least the inner upper half of the tunnel cross section is covered with a covering material, and an invert is formed at the lower part of the tunnel cross section. And build a structure
A support process for installing the support work at the tunnel construction site;
An outer lining frame installation step of installing an outer lining frame on the outer side of the installed support;
An inner beam installation step of installing an inner beam between the lower ends of the support works so as to close the cross section of the support work;
A backfilling step of backfilling the upper part of the outer lining frame with the poor compounding backfilling material;
After curing the poor compounding backfill material, an inner beam removal step of removing the inner beam,
An inversion step of forming an invert at a lower portion of the tunnel cross section,
The tunnel construction method according to claim 1, which is performed in this order. While measuring the tunnel cross section,
The tunnel construction method according to claim 2, wherein when the displacement in each step in the backfilling step, the inner beam removing step, and the inverting step is within a preset management reference value, the next step is performed. In the backfilling step,
The tunnel construction method according to claim 2 or 3, wherein the upper portion of the poor-mixed backfill material that has been backfilled is backfilled with backfill earth and sand. While making the tunnel construction site a digging tunnel tunnel to be constructed by excavation,
The tunnel construction method according to any one of claims 2 to 4, wherein a tunnel is constructed to construct a tunnel. The tunnel construction point is
The tunnel construction method according to any one of claims 1 to 4, wherein a passage crossing portion is constructed in which a passage through which a passing body passes is refilled. A tunnel structure in which a tunnel is constructed by backfilling the upper part of the tunnel structure installed at the tunnel construction site,
After building at least the upper half of the tunnel structure,
A tunnel structure constructed by backfilling the upper part of the upper half portion with a poorly blended poorly blended backfill material. The tunnel structure is installed at a predetermined interval in the tunnel axial direction, and has an upwardly projecting arch-shaped support, a covering material that covers at least the inner upper half of the tunnel cross section, and the tunnel cross section It consists of inverts formed at the bottom,
The support construction is installed at the tunnel construction site, an outer lining frame is installed outside the installed support construction, and the spray material is sprayed between the support works in the tunnel axial direction. While removing the inner beam installed so as to close the cross section of the support work between the lower ends of the work, after curing the poor compounded poor backfill material that backfilled the upper part of the outer lining frame, The tunnel structure according to claim 7, wherein an invert is formed at a lower portion of the tunnel cross section. While measuring the tunnel cross section,
The tunnel structure according to claim 8, wherein the next step is performed after confirming that the displacement of each step in the backfilling step, the inner beam removing step, and the inverting step is within a preset management reference value. object. The tunnel structure according to claim 8 or 9, wherein an upper part of the poor-mixed backfill material backfilled is backfilled with backfill earth and sand. While making the tunnel construction site a digging tunnel tunnel to be constructed by excavation,
The tunnel structure according to any one of claims 8 to 10, wherein a tunnel is constructed after lining the invert. The tunnel construction point is
The tunnel structure according to any one of claims 7 to 11, which is a road crossing portion in which a road through which a passing body passes is refilled.

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