Drainage type drainage system for karst tunnel
Technical Field
The invention relates to the technical field of tunnel engineering, in particular to a drainage system of a karst tunnel.
Background
In recent years, the traffic industry such as railways, roads and the like in China is rapidly developed, and the number and the mileage of tunnels are continuously increased. Under the influence of complex geological environment and hydrogeological conditions, the construction and operation process of the tunnel still faces a plurality of engineering diseases at present. Karst tunnels in the southwest are widely distributed, karst water causes great harm to a tunnel lining structure, water pressure acts on the lining to change the stress characteristic of the lining structure, and the large water pressure behind the lining increases the load behind the tunnel structure, so that the generation of diseases such as tunnel lining cracking, inverted arch rising, grout pumping and the like is caused. Therefore, the drainage of the underground water behind the lining is very important. However, due to irregular distribution of karst fractures in a karst region, drainage blind spots often exist in drainage of the currently adopted lining back ring longitudinal blind pipes, and after a drainage channel formed by rock fractures is blocked in the later period, long-term effective drainage cannot be performed, so that the problem that tunnel lining damage is caused by unsmooth drainage is caused.
Disclosure of Invention
The invention aims to: aiming at the problem of difficult drainage of the karst tunnel in the prior art, the drainage type drainage system of the karst tunnel is provided.
In order to achieve the purpose, the invention adopts the technical scheme that:
a drainage type drainage system of a karst tunnel, which comprises a drill hole, a drainage network, a drainage pipe and a tunnel drainage ditch, the drill holes are declined drill holes which are punched from the tunnel arch wall to the karst development area, the drainage network is located on the soil or rock mass near the bottom end of the drill hole, at least part (or all) of the drainage network is located in the karst development area, the drainage network comprises a plurality of cracks, pervious concrete is filled in the cracks, all the cracks are communicated with each other, a drain pipe is laid in the drill hole, the water inlet of the drain pipe is communicated with the drainage network, the delivery port of drain pipe with the tunnel escape canal is linked together, the elevation of the water inlet of drain pipe is less than the elevation of the delivery port of drain pipe, just the elevation on drilling top is higher than the elevation of the delivery port of drain pipe.
Along with the development of karst, groundwater concentrates near the water inlet of drain pipe gradually through drainage network, and when the groundwater level line of drain pipe water inlet department improved, because the siphon effect, groundwater will be carried to the tunnel escape canal through the drain pipe, until the water level of drain pipe water inlet department equals the water level of the delivery port department of drain pipe, then accomplish once automatic drainage. The above automatic drainage process will occur many times during the operation of the tunnel.
The drainage system for the karst tunnel provided by the invention utilizes the siphon effect, can automatically and efficiently drain redundant underground water in the surrounding rock of the tunnel in real time as long as the underground water is gathered, and does not need any external power or manual maintenance. According to the invention, the pervious concrete is pressed into the surrounding rock of the tunnel under high pressure, and the pervious concrete forms a drainage network with high porosity after solidification, so that underground water is gathered near the drilled hole, the influence range of a single drainage hole on the generation of a landing funnel is enlarged, water is drained efficiently at one time, and the drainage efficiency can be obviously improved.
In a preferred embodiment of the present invention, a plurality of injection holes are circumferentially arranged along the borehole, and each slit is communicated with at least one of the injection holes. The jet holes are used for communicating the cracks with the drill holes, and the jet holes are convenient for jetting pervious concrete.
In a preferred embodiment of the present invention, the permeable concrete has a permeability coefficient of 0.01m/d or more, and is made of aggregate, cement, a reinforcing agent, and water.
As the preferable scheme of the invention, at least two drain pipes are arranged in the drill hole, so that the drainage efficiency is improved.
In a preferred embodiment of the present invention, a part of the drain pipe is laid in the drilled hole, and another part of the drain pipe is fixed to the inner wall of the tunnel.
As a preferable scheme of the invention, the lift of the drain pipe is smaller than the height of a water column corresponding to the atmospheric pressure of a construction site.
As a preferable scheme of the invention, the inclination angle of the drill hole is 10-30 degrees.
In a preferred embodiment of the present invention, the diameter of the bore is greater than or equal to 70 mm.
As a preferable scheme of the invention, the drain pipe is a PU pipe.
As a preferable scheme of the invention, the diameter of the drain pipe is more than or equal to 4 mm.
As a preferable scheme of the present invention, the tunnel drainage ditch is a tunnel side ditch, a water collection tank is arranged in the tunnel side ditch, and a water outlet of the drainage pipe is located in the water collection tank.
The invention also discloses a drainage method for the karst tunnel, which comprises the following steps:
the method comprises the following steps: according to a geological survey result, preliminarily determining a karst development area of the tunnel, and drilling downward inclined holes facing the karst development area from the tunnel arch wall. And if the drill hole can be directly drilled to the karst development area, directly drilling to the karst development area, and if the drill hole can not be directly drilled to the karst development area, drilling to the position near the karst development area as much as possible, so that after the pervious concrete is injected, at least part of the formed drainage network can be positioned in the karst development area, and the underground water of the karst development area is led out.
Step two: and placing a multi-nozzle sleeve at the bottom end of the drilled hole, wherein the multi-nozzle sleeve comprises a grouting hole, a plurality of jet holes and a movable sleeve, the movable sleeve is respectively connected with the grouting hole and the high-pressure pump, the movable sleeve is connected with the high-pressure pump, and the high-pressure pump is used for injecting pervious concrete into the multi-nozzle sleeve.
Step three: after the pervious concrete is injected, the movable sleeve is dismantled, and a water inlet of a drain pipe is placed at the bottom end of the drilled hole;
step four: and reversely filling water from the water outlet of the drain pipe, stopping reversely filling water after all the air in the drain pipe is discharged, and putting the water outlet of the drain pipe into a tunnel drainage ditch. According to the calculated volume of the drain pipe, the amount of water greater than or equal to the volume is injected, so that all the air in the drain pipe can be discharged.
According to the drainage method, the high-pressure pump is used for injecting the pervious concrete into the multi-nozzle sleeve, the pervious concrete enters the soil body or the rock body from the injection hole, the pervious concrete develops along the weak area of the soil body or the rock body, the whole crack space is filled and solidified when stratum rock and soil are fractured, a space high-permeability drainage network is formed, and underground water is drained to the drilling hole. And then the drain pipe is communicated between the drill hole and the tunnel drainage ditch, when the water level of the water inlet of the drain pipe is higher than that of the water outlet, the siphon effect is generated, the underground water is automatically discharged, after the primary drainage process is finished, the water inlet and the water outlet of the drain pipe are both positioned below the water surface, and air cannot enter the drain pipe, so that the drain pipe is kept in a vacuum state. When the ground water level at the water inlet rises again, the siphon action occurs again and the drain pipe drains water again.
The drainage method can automatically drain the underground water for multiple times in real time during the whole tunnel operation period only by once construction, and the drainage process automatically occurs without manual maintenance. The method utilizes the pervious concrete to be injected into the drilled hole, and can more easily and accurately position the karst development area along the crack direction of the rock-soil body under the condition that the karst development area is uncertain.
In a preferred embodiment of the present invention, all of the injection holes are uniformly arranged along a circumferential direction of the multi-nozzle casing.
As a preferable scheme of the invention, the multi-nozzle sleeve is a metal sleeve.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. the drainage system for the karst tunnel provided by the invention utilizes the siphon effect, can automatically and efficiently drain redundant underground water in the surrounding rock of the tunnel in real time as long as the underground water is gathered, and does not need any external power or manual maintenance.
2. According to the invention, the pervious concrete is pressed into the surrounding rock of the tunnel under high pressure, and the pervious concrete forms a drainage network with high porosity after solidification, so that underground water is gathered near the drilled hole, the influence range of a single drainage hole on the generation of a landing funnel is enlarged, water is drained efficiently at one time, and the drainage efficiency can be obviously improved.
3. The drainage method can automatically drain the underground water for multiple times in real time during the whole tunnel operation period only by once construction, and the drainage process automatically occurs without manual maintenance.
4. The method utilizes the pervious concrete to be injected into the drilled hole, and can more easily and accurately position the karst development area along the crack direction of the rock-soil body under the condition that the karst development area is uncertain.
Drawings
Fig. 1 is a schematic structural diagram of a drainage system of a karst tunnel according to the first embodiment of the invention.
Fig. 2 is a schematic structural diagram of a drainage system of a karst tunnel according to the present invention.
FIG. 3 is a schematic diagram of a multiple nozzle tip cartridge according to the present invention.
Fig. 4 is a cross-sectional view of a tunnel lateral groove according to the present invention.
Fig. 5 is a plan view of a tunnel lateral groove according to the present invention.
Icon: 1-tunnel, 2-drilling, 3-multi-nozzle casing, 31-grouting hole, 32-injection hole, 33-movable casing, 4-pervious concrete, 5-drainage pipe, 6-tunnel side ditch, 61-water collecting tank, 7-karst development area and 8-underground water level line.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
A drainage type drainage system for a karst tunnel comprises a drill hole 2, a drainage network, a drainage pipe 5 and a tunnel drainage ditch.
The drill hole 2 is a declination drill hole, the inclination angle of the drill hole 2 is 10-30 degrees, and the diameter of the drill hole 2 is larger than or equal to 70 mm. The bore hole 2 is driven directly into the karst development zone 7 of the tunnel 1, as shown in figure 1; or the borehole 2 is not driven into the karst development zone 7 of the tunnel 1, but is located adjacent to the karst development zone 7, as illustrated in figure 2.
A multi-nozzle casing 3 is provided at the bottom end of the borehole 2, as shown in fig. 3, the multi-nozzle casing 3 includes a grouting hole 31, a plurality of injection holes 32, and a movable casing 33, and all the injection holes 32 are arranged circumferentially along the multi-nozzle casing 3. The grouting holes 31 are located in the drill holes 2, the grouting holes 31 are detachably connected with the movable sleeve 33, the movable sleeve 33 is connected with a high-pressure pump, the high-pressure pump is used for injecting permeable concrete 4 into the multi-nozzle sleeve 3, the permeable concrete 4 enters a soil body or a rock body from the injection holes 32, the permeable concrete 32 develops along a weak area of the soil body or the rock body, and when stratum rock soil is fractured, the whole crack space is filled and solidified to form a space high-permeability drainage network. After the pervious concrete 4 is poured, the movable sleeve 33 is removed, and the grouting hole 31 is communicated with the drain pipe 5. The direction of the grouting is shown by the arrow in fig. 3.
The drainage network is positioned on a soil body or a rock body near the bottom end of the drilling hole 2, at least part (or all) of the drainage network is positioned in the karst development area 7, the drainage network comprises a plurality of cracks, permeable concrete 4 is filled in the cracks, all the cracks are mutually communicated, each crack is at least communicated with one injection hole 32, the permeability coefficient of the permeable concrete 4 is greater than or equal to 0.01m/d, and the permeable concrete 4 is made of aggregate, cement, reinforcing agent and water.
At least two drain pipes 5 have been laid in drilling 2, drain pipe 5 is diameter 4 mm's PU pipe, drain pipe 5's lift is less than the water column height that construction site atmospheric pressure corresponds. One part of the drain pipe 5 is laid in the drilled hole, and the other part of the drain pipe 5 is fixed on the inner wall of the tunnel 1. And the water inlet of the drain pipe 5 is communicated with the drain network, and the water outlet of the drain pipe 5 is communicated with the tunnel drain. Specifically, as shown in fig. 4 to 5, the tunnel drainage ditch is a tunnel side ditch 6, a water collection tank 61 is arranged in the tunnel side ditch 6, and a water outlet of the drainage pipe 5 is located in the water collection tank 61.
The elevation of the water inlet of the drain pipe 5 is lower than that of the water outlet of the drain pipe 5, and the elevation of the top end of the drilling hole 2 is higher than that of the water outlet of the drain pipe 5.
Due to the arrangement of the drainage system, the underground water is gradually concentrated to the position near the water inlet of the drainage pipe 5 through the drainage network, when the underground water level line 8 at the water inlet of the drainage pipe 5 is increased, the underground water is conveyed to the water collecting tank 61 through the drainage pipe 5 due to the siphoning effect until the water level at the water inlet of the drainage pipe 5 is equal to the water level at the water outlet of the drainage pipe 5, and one-time automatic drainage is completed. The above automatic drainage process will occur many times during the operation of the tunnel.
Example 2
As shown in fig. 1 to 5, a drainage method for karst tunnels comprises the following steps:
the method comprises the following steps: according to a geological survey result, a karst development area 7 of the tunnel 1 is preliminarily determined, and a downward inclined drill hole 2 facing the karst development area 7 is drilled from the arch wall of the tunnel 1. If the drill hole 2 can be directly drilled to the karst development area 7, the drill hole is directly drilled to the karst development area 7, if the drill hole 2 cannot be directly drilled to the karst development area 7, the drill hole is drilled to the position near the karst development area 7 as far as possible, so that after the pervious concrete 4 is injected, at least part of the formed drainage network can be located in the karst development area 7, and the underground water of the karst development area 7 is led out.
Step two: the bottom of drilling 2 places many shower nozzles sleeve pipe 3, many shower nozzle sleeve pipe 3 includes injected hole 31, a plurality of jet orifice 32 and movable sleeve pipe 33, will movable sleeve pipe 33 respectively with injected hole 31, high-pressure pump are connected, utilize the high-pressure pump to in the many shower nozzle sleeve pipe 3 pour into pervious concrete 4. The pervious concrete 4 enters the soil body or rock body from the injection hole 32, the pervious concrete 32 develops along the weak area of the soil body or rock body, and the whole crack space is filled and solidified when stratum rock and soil are fractured, so that a spatial high-permeability drainage network is formed.
Step three: and after the pervious concrete 4 is injected, the movable sleeve 33 is removed, and the water inlet of the drain pipe 5 is placed at the bottom end of the drill hole 2.
Step four: and reversely filling water from the water outlet of the drain pipe 5, stopping reversely filling water after all the air in the drain pipe 5 is discharged, and putting the water outlet of the drain pipe 5 into the water collecting tank 61 of the tunnel side ditch 6. Based on the calculated volume of the drain pipe 5, the amount of water greater than or equal to the volume is injected, so that all the air in the drain pipe 5 can be discharged.
According to the drainage method, the high-pressure pump is used for injecting the pervious concrete into the multi-nozzle sleeve, the pervious concrete enters the soil body or rock body from the injection hole to form a spatial high-permeability drainage network, and underground water is drained to the drill hole. And then the drain pipe is communicated between the drill hole and the tunnel drainage ditch, when the water level of the water inlet of the drain pipe is higher than that of the water outlet, the siphon effect is generated, the underground water is automatically discharged, after the primary drainage process is finished, the water inlet and the water outlet of the drain pipe are both positioned below the water surface, and air cannot enter the drain pipe, so that the drain pipe is kept in a vacuum state. When the ground water level at the water inlet rises again, the siphon action occurs again and the drain pipe drains water again.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.