CN113323723B

CN113323723B - Acid-soluble drilling drainage structure for tunnel and side slope of karst or fault and construction method

Info

Publication number: CN113323723B
Application number: CN202110711425.3A
Authority: CN
Inventors: 范雲鹤; 郑长青; 喻渝; 赵万强; 曹彧; 胖涛; 谭永杰; 刘金松; 罗禄森; 周羽哲; 王李
Original assignee: China Railway Eryuan Engineering Group Co Ltd CREEC
Current assignee: China Railway Eryuan Engineering Group Co Ltd CREEC
Priority date: 2021-06-25
Filing date: 2021-06-25
Publication date: 2021-11-16
Anticipated expiration: 2041-06-25
Also published as: CN113323723A

Abstract

The invention relates to the field of civil engineering and discloses a drainage structure of a tunnel and a side slope of a karst or fault and a construction method. The utility model provides an acid-soluble drilling drainage structure, including passing through empty section and slip casting section, it is located the lower part of the drilling that has a down dip to pass through empty section, the slip casting section is located drilling upper portion, set up the stagnant water component between empty section and the slip casting section, it is equipped with the pipe of permeating water in the empty section to pass through, it has the cavity to permeate water intraductally, it is provided with the drain pipe that passes the outside extension of stagnant water component to permeate water intraductally, it has the solid filling material that can dissolve in acid and water insoluble to permeate water intussuseption, stagnant water component lower part, permeate water pipe and drain pipe are acid-fast material or have acid-fast top layer. By the drainage structure and the construction method, grouting pressure can be guaranteed, and controllability of drainage structure construction is improved.

Description

Acid-soluble drilling drainage structure for tunnel and side slope of karst or fault and construction method

Technical Field

The invention relates to the field of civil engineering, in particular to a drainage structure of a tunnel and a side slope of a karst or fault and a construction method.

Background

When a waterproof layer or a lining structure of a tunnel has defects, local groundwater seepage can occur. Particularly, water-rich karst and fault tunnels are serious in water seepage, and the problems of water accumulation, icing and the like caused by water seepage of tunnel walls entering the tunnels influence the operation safety of the tunnels. In addition, the seepage damages the tunnel lining concrete and the surrounding rock internal structure, reduces the durability of the tunnel structure, and shortens the service life of the tunnel.

For a gas tunnel, the water seepage of the tunnel is often mixed with harmful gases such as gas, part of the harmful gases have combustibility and explosiveness, and the escape of the harmful gases into the tunnel can pose a safety threat to the operation period of the tunnel.

The Chinese patent application with publication number CN107237650A proposes a tunnel water seepage negative pressure drainage technology, the core idea of which is to inject slurry into a grouting closed drilling section, reserve a permeable drilling section, and form negative pressure in the permeable drilling section under the action of drainage to force the underground water of tunnel surrounding rock to flow to the drilling hole quickly and discharge the surface. The drilling section of permeating water is isolated with external atmosphere, and before the drainage process takes place, the downthehole pressure can progressively increase along with the infiltration of groundwater, makes groundwater flow drill way naturally, and after the drainage process takes place, because the drainage ability of drain pipe is greater than the flow that groundwater infiltrates the cavity of the drilling section of permeating water, can the vacuole formation in the pipe of permeating water, the atmospheric pressure of cavity is less than atmospheric pressure (negative pressure promptly), therefore the water in the pipe of permeating water surrounding the soil body to the pipe of permeating water. Similarly, because there is the negative pressure in the pipe of permeating water, the water of all directions all can flow to the pipe of permeating water around the pipe of permeating water, therefore, the drainage range can increase, and the drainage range increase more is favorable to the groundwater in the discharge tunnel country rock.

However, in the tunnel water seepage negative pressure drainage technology, in the field construction process, the lower half part of a drilled hole is a water permeable drilled section, the water permeable effect needs to be kept, the grouting for grouting the sealed drilled section cannot enter the water permeable drilled section, if the grouting pressure is high, partition structures such as an expansion rubber water stop ring and the like are often broken, and slurry enters the water permeable drilled section, so that the drilled hole is failed; if the grouting pressure is low, the effect of blocking and sealing the drilling section cannot be achieved, and the negative pressure effect cannot be formed. Therefore, a new grouting technique is required to solve the above problems.

For another example, chinese patent application publication No. CN111794238A proposes a grouting structure and a construction method for filling soluble crystals, which utilizes a permeable pipe filled with soluble crystals such as solid salt, solid sugar, solid alum, and solid ice to increase grouting pressure, reduce cracks in the grouting section, improve sealing effect, and further improve negative pressure effect of the permeable section. However, in engineering field tests, the melting of soluble crystals is difficult to control artificially, and if the construction of a grouting section is stopped and the slurry is not solidified sufficiently, ice blocks are gradually melted by the action of underground water, ambient temperature and the like, so that the effect of isolating the slurry cannot be achieved.

Disclosure of Invention

The invention aims to provide an acid-soluble drilling drainage structure and a construction method for karst or fault tunnels and side slopes, so that the construction controllability of the drainage structure is improved.

The invention discloses an acid-soluble drilling drainage structure of a karst or fault tunnel and a side slope, which comprises a permeable section and a grouting section, wherein the permeable section is positioned at the lower part of a declined drill hole, the grouting section is positioned at the upper part of the drill hole, a water stopping component is arranged between the permeable section and the grouting section, a permeable pipe is arranged in the permeable section, a cavity is arranged in the permeable pipe, a drainage pipe which penetrates through the water stopping component and extends outwards is arranged in the permeable pipe, a solid filling material which can be dissolved in acid and is not dissolved in water is filled in the permeable pipe, and the lower part of the water stopping component, the permeable pipe and the drainage pipe are all made of acid-resistant materials or have acid-resistant surface layers.

Preferably, an acid injection pipe extending outwards through the water stopping member is arranged in the water permeable pipe, the inner end part of the acid injection pipe is positioned at the position, close to the water stopping member, of the upper part of the water permeable pipe, and the inner end part of the water discharge pipe is positioned at the bottom of the water permeable pipe.

Preferably, the inner end of the acid injection pipe is sleeved with a water-permeable shell made of the same material as the solid filling material.

Preferably, a pressurizing bag body is arranged in the water permeable pipe, and the pressurizing bag body is connected with a pressurizing pipe which penetrates through the water stopping component and extends outwards.

Preferably, the pressurizing capsule is made of a material which can be dissolved in acid.

Preferably, the water stopping member includes a water-swellable rubber water stopping ring at an upper portion and an acid-resistant gasket at a lower portion.

Preferably, the solid filler material is calcium carbonate.

The construction method of the acid-soluble drilling drainage structure for the tunnel and the side slope of the karst or fault comprises the following steps:

determining the position of the drilled drainage hole, and performing drilling construction;

a water permeable pipe is placed in the hollow section at the lower part of the drill hole, and a drain pipe extending into the water permeable pipe is placed in the drill hole;

placing a solid filling material which is soluble in acid and insoluble in water into the water permeable pipe, compacting and filling the permeable section, and arranging a water stopping member between the permeable section and the grouting section;

injecting mortar into the grouting section;

and after the grouting is finished and the slurry at the grouting section is solidified and reaches the maximum strength, injecting an acid solution into the water permeable pipe, and dissolving the solid filling material.

Preferably, after the permeable pipe is placed, an acid injection pipe extending into the permeable pipe is placed in the drill hole, the inner end part of the acid injection pipe is positioned at the position, close to the water stop member, of the upper part of the permeable pipe, the inner end part of the water discharge pipe is positioned at the bottom of the permeable pipe, and then the solid filling material is placed;

when acid solution is injected into the water permeable pipe, the acid solution is injected through the acid injection pipe, and liquid substances in the water permeable pipe are extracted by the water discharge pipe until the extracted substances are pure acid solution.

Preferably, after the solid filling material is dissolved, the acid injection tube exposed out of the dissolving tube is cut off, polyurethane is injected into the acid injection tube, and the acid injection tube is closed.

Preferably, after the water permeable pipe is placed, a pressurizing bag body is placed in the drill hole, and the pressurizing bag body is connected with a pressurizing pipe extending outwards;

and injecting fluid into the pressurizing bag body through the pressurizing pipe for pressurizing while injecting mortar.

Preferably, after the solid filling material is dissolved, the exposed pressurizing pipe of the dissolving pipe is cut off, polyurethane is injected into the pressurizing pipe, and the pressurizing pipe is sealed.

Preferably, the injected acidic solution is an acetic acid solution.

Preferably, the acetic acid solution is heated and then injected into the water permeable tube.

The invention has the following beneficial effects:

1. the invention adopts the phase change technology to arrange the calcium carbonate solid particles in the permeable section, thereby preventing the grouting from entering the permeable section and preventing the water stop member from being extruded to generate larger displacement. Meanwhile, compared with methods of filling ice and soluble crystals, the method has the advantages that the problem that soluble crystals such as ice are difficult to transport and store in mountainous engineering sites and the problem that the dissolution time of calcium carbonate is uncontrollable due to the influence of air temperature, underground water and the like can be solved.

2. The permeable section is filled with calcium carbonate solid matter, grouting pressure can be increased during grouting, the filling rate of slurry in the cracks of the grouting section is high, the effect of sealing the grouting section can be better achieved, and the technical effect of negative pressure drainage is achieved.

3. The invention can realize the real-time discharge of slope groundwater, tunnel deep groundwater and the like after being started, and solves the problems of karst, fault, altered zone, joint dense zone and gas tunnel water seepage.

4. The grouting section has a sealing function, harmful gases such as gas can be prevented from escaping and entering the tunnel, negative pressure is formed in the through section under the action of siphonage in the drainage and exhaust processes, and harmful gases such as surrounding rock underground water and gas are forced to rapidly flow to the drill hole and are discharged out of the tunnel. Realizes the water-gas separation outside the tunnel, and is safe and effective.

5. The tunnel gas and other harmful gases have low density and are easy to gather upwards, and the negative pressure area formed by the invention has suction and discharge functions on the harmful gases, so that the gas is discharged more effectively.

Drawings

FIG. 1 is a schematic diagram of one embodiment of the present invention for use in a tunnel;

FIG. 2 is an enlarged view of the borehole of FIG. 1;

FIG. 3 is a schematic view of an embodiment of the present invention for use in tunnels and incorporating a pressurizing bladder;

FIG. 4 is an enlarged view of the borehole of FIG. 3;

FIG. 5 is a schematic longitudinal section view of the water outlet of the drain pipe of the present invention disposed outside the tunnel;

fig. 6 is a schematic view of an embodiment of the invention for a side slope.

Reference numerals: a tunnel 1; a side groove 11; a tunnel external water tank 12; an underground water line 2; drilling 3; a grouting section 31; a clear section 32; a water permeable pipe 4; a water stopping member 5; a water-swellable rubber water stop ring 51; an acid-resistant gasket 52; a water discharge pipe 6; a water permeable pipe shoe 61; an acid injection pipe 7; a water permeable casing 71; a solid filler material 8; pressurizing the capsule 9; a pressurizing tube 91; a hydraulic pump 92, a slope 10.

Detailed Description

The present invention is further described below.

The invention discloses an acid-soluble drilling hole 3 drainage structure of a karst or fault tunnel and side slope, which comprises a permeable section 32 and a grouting section 31, wherein the permeable section 32 is positioned at the lower part of a declined drilling hole 3, the grouting section 31 is positioned at the upper part of the drilling hole 3, a water-stopping member 5 is arranged between the permeable section 32 and the grouting section 31, a permeable pipe 4 is arranged in the permeable section 32, a cavity is arranged in the permeable pipe 4, a drainage pipe 6 which penetrates through the water-stopping member 5 and extends outwards is arranged in the permeable pipe 4, a solid filling material 8 which can be dissolved in acid and is not dissolved in water is filled in the permeable pipe 4, and the lower part of the water-stopping member 5, the permeable pipe 4 and the drainage pipe 6 are all made of acid-resistant materials or have acid-resistant surface layers to prevent corrosion by acid solution.

The construction method of the drainage structure comprises the following steps:

determining the position of the drilled drainage hole 3, and performing the construction of the hole 3, for example, for tunnel drainage, investigating the position and the range of a hole wall water seepage point of a section enriched with harmful gases such as tunnel karst, fault, joint dense zone, altered zone, gas and the like;

a permeable pipe 4 is placed in a permeable section 32 at the lower part of a drill hole 3, a drain pipe 6 extending into the permeable pipe 4 is placed in the drill hole 3, the specific arrangement mode of the drain pipe 6 can refer to the existing tunnel drain pipe 6, generally, the elevation of a water inlet of the drain pipe 6 is greater than that of a water outlet of the drain pipe 6, the lift of the drain pipe 6 is smaller than the height of a water column corresponding to the atmospheric pressure in the tunnel, and a permeable pipe boot 61 can be arranged at the water inlet of the drain pipe 6;

placing a solid filling material 8 which is soluble in acid and insoluble in water into the water permeable pipe 4, compacting and filling the permeable section 32, and arranging a water stopping member 5 between the permeable section 32 and the grouting section 31;

injecting mortar into the grouting section 31, wherein a retreating grouting method is preferably adopted for grouting;

after grouting, after the slurry of the grouting section 31 is solidified and reaches the maximum strength, acid solution is injected into the water permeable pipe 4, and the solid filling material 8 is dissolved, so that the construction of the drainage structure is completed. When the underground water level line 2 inside the tunnel surrounding rock or the side slope rises to cause the water head height of the water inlet of the water discharge pipe 6 to be larger than the orifice elevation of the drill hole 3, underground water in the permeable section 32 is discharged by the water discharge pipe 6 under the action of the water head difference, and with the continuous occurrence of the water discharge process, siphonage can be generated and negative pressure is generated in the permeable section 32, so that the underground water in the surrounding rock flows into the permeable section 32 at an accelerated speed, and when the tunnel surrounding rock near the drill hole 3 and the underground water in the permeable section are drained, the suction and discharge functions of the water discharge pipe 6 disappear, and the primary water discharge process is finished. As shown in fig. 1-5, the present invention can be used for drainage of a tunnel 1, and as shown in fig. 6, the present invention can also be used for drainage of a slope 10. As shown in fig. 1 and 4, the drain pipe 6 may be introduced into the side trench 11 or the center trench during tunnel drainage, or may be introduced into the tunnel external water tank 12 as shown in fig. 5.

When the acid solution is injected into the water permeable pipe 4, it can be directly injected through the water discharge pipe 6, but this injection mode is difficult to implement due to the internal pressure, and therefore, as shown in fig. 1 and 2, in the preferred embodiment of the present application, an acid injection pipe 7 extending outward through the water stopping member 5 is provided in the water permeable pipe 4, the inner end portion of the acid injection pipe 7 is located at a position where the upper portion of the water permeable pipe 4 is close to the water stopping member 5, and the inner end portion of the water discharge pipe 6 is located at the bottom of the water permeable pipe 4. After placing the permeable tube 4, an acid injection tube 7 extending into the permeable tube 4 is placed in the bore hole 3, and then a solid packing material 8 is placed. When acid solution is injected into the water permeable pipe 4, the acid solution is injected through the acid injection pipe 7, and the liquid substance in the water permeable pipe 4 is pumped out by the water discharge pipe 6 until the pumped out substance is pure acid solution, namely, the solid filling material 8 is completely dissolved. After the solid filling material 8 is dissolved, the acid injection pipe 7 exposed out of the dissolving pipe is cut off, polyurethane is injected into the acid injection pipe 7, and the acid injection pipe 7 is closed.

In order to provide a dissolving space for the acidic solution and increase the contact area between the acidic solution and the solid filling material 8, a water-permeable shell 71 made of the same material as the solid filling material 8 is sleeved at the inner end of the acid injection pipe 7.

In order to solve the problem that the solid filling material 8 in the water permeable pipe 4 is usually made of granular material, and the filling requires compaction, but it is inconvenient to squeeze the water permeable pipe 4 and the water discharge pipe 6 excessively due to the existence of the pipes, and the like, so as to prevent the pipes from being damaged, however, when the grouting section 31 injects mortar, the water stop member 5 may move backwards due to insufficient supporting force provided by the solid filling material 8, and the grouting quality is affected, as shown in fig. 3 and 4, in the preferred embodiment of the present application, a pressurizing capsule 9 is arranged in the water permeable pipe 4, and the pressurizing capsule 9 is connected with a pressurizing pipe 91 extending outwards through the water stop member 5. After the water permeable pipe 4 is placed, a pressurizing bag body 9 is placed in the drill hole 3, and the pressurizing bag body 9 is connected with a pressurizing pipe 91 extending outwards; at the same time of injecting the mortar, the pressurizing bladder 9 is pressurized by injecting a fluid through the pressurizing pipe 91 by the pressurizing pump 92. When grouting, the support pressure below the pressurizing bag 9 is increased to prevent the water stopping member 5 from displacing. The pressurizing pressure of the pressurizing capsule 9 is preferably slightly larger than the grouting pressure, and the difference value between the grouting pressure and the pressurizing pressure keeps a certain value, so that the grout cannot bypass into the through hollow section 32, and the certain value can be measured by a test. The specific pressurizing fluid for pressurizing the bladder 9 may be a gas or a liquid, and most commonly air or water. Similarly, after the solid filler 8 is dissolved, the pressurizing pipe 91 exposed from the dissolving pipe is cut off, and polyurethane is injected into the pressurizing pipe 91 to close the pressurizing pipe 91. In order to prevent the possible adverse effect of the pressurizing bladder 9 on the subsequent drainage, the pressurizing bladder 9 is made of a material that is soluble in acid, such as unsaturated rubber.

It is mentioned that the lower part of the water stopping member 5, the water permeable pipe 4 and the water discharging pipe 6 are made of acid-proof material or have acid-proof surface layer, the water permeable pipe 4, the water discharging pipe 6 and the acid injecting pipe 7 can all be made of polypropylene material with better corrosion resistance, and the water stopping member 5 can include a water-swelling rubber water stopping ring 51 at the lower part and the acid-proof gasket 52 and at the upper part. The acid-resistant gasket 52 may also be made of polypropylene, and the water-swellable rubber water stop ring 51 on the upper portion can ensure that the slurry does not enter the permeable section 32 during grouting.

The solid filling material 8 is required to be soluble in acid and insoluble in water, and can adopt insoluble salts, alkalis, metal oxides and the like, wherein calcium carbonate is the best, the cost is low, the solid filling material is easy to obtain, store and transport, in addition, calcium carbonate-containing stone materials such as limestone, marble and the like can be collected nearby and processed into particles to be used as the solid filling material 8, the acidic solution generally adopts weak acidic solution such as acetic acid and the like, and the weak acidic solution can be injected into the water permeable pipe 4 after being heated for accelerating the dissolution.

Claims

1. Acid-soluble drilling drainage structure for tunnels and side slopes of karst or fault, which comprises a permeable section (32) and a grouting section (31), wherein the permeable section (32) is positioned at the lower part of a declined drill hole (3), the grouting section (31) is positioned at the upper part of the drill hole (3), a water-stopping member (5) is arranged between the permeable section (32) and the grouting section (31), a permeable pipe (4) is arranged in the permeable section (32), a cavity is arranged in the permeable pipe (4), a drainage pipe (6) which extends outwards through the water-stopping member (5) is arranged in the permeable pipe (4), and the acid-soluble and water-insoluble solid filling material (8) is filled in the permeable pipe (4), the permeable section (32) is filled with the solid filling material (8) in a compaction mode, mortar is injected into the grouting section (31), and after grouting is finished, the grout in the grouting section (31) is solidified and reaches the maximum strength, acid solution is injected into the water permeable pipe (4) to dissolve the solid filling material (8), and the lower part of the water stopping component (5), the water permeable pipe (4) and the drain pipe (6) are all made of acid-resistant materials or have acid-resistant surface layers.

2. The acid-soluble drilling drainage structure for karst or fault tunnels and slopes as claimed in claim 1, wherein an acid injection pipe (7) extending outwards through the water-stop member (5) is arranged in the water-permeable pipe (4), the inner end of the acid injection pipe (7) is located at the position where the upper part of the water-permeable pipe (4) is close to the water-stop member (5), and the inner end of the drainage pipe (6) is located at the bottom of the water-permeable pipe (4).

3. The acid-soluble drilling drainage structure for tunnels and slopes of karsts or faults as claimed in claim 2, wherein the inner end of the acid injection pipe (7) is sleeved with a water-permeable casing (71) made of the same material as the solid filling material (8).

4. Acid-soluble drilling drainage structure for karst or fault tunnels and slopes according to claim 1, characterized in that a pressurizing bag (9) is arranged in the water permeable pipe (4), and the pressurizing bag (9) is connected with a pressurizing pipe (91) extending outwards through the water stop member (5).

5. Acid-soluble bore drainage structure for tunnels and slopes in karsts or faults according to claim 4, characterized in that the pressurizing capsules (9) are made of acid-soluble material.

6. Acid-soluble bore hole drainage structures of tunnels and slopes of karsts or faults according to claim 1, characterized in that the water stop means (5) comprise an acid-resistant gasket (52) at the lower part and a water-swellable rubber water stop ring (51) at the upper part.

7. Acid-soluble drill drainage structures for tunnels and slopes of karsts or faults according to any of claims 1 to 6, characterized in that the solid filling material (8) is calcium carbonate.

8. The construction method of the acid-soluble drilling drainage structure for the tunnel and slope of the karst or fault according to any one of claims 1 to 7, characterized by comprising the steps of:

determining the position of the drilled drainage hole (3), and constructing the drilled drainage hole (3);

a water permeable pipe (4) is placed in a hollow section (32) at the lower part of the drilling hole (3), and a drain pipe (6) extending into the water permeable pipe (4) is placed in the drilling hole (3);

placing a solid filling material (8) which is soluble in acid and insoluble in water into the permeable pipe (4), compacting and filling the permeable section (32), and arranging a water stopping member (5) between the permeable section (32) and the grouting section (31);

injecting mortar into the grouting section (31);

after grouting is finished, after the grout in the grouting section (31) is solidified and reaches the maximum strength, acid solution is injected into the permeable pipe (4), and the solid filling material (8) is dissolved.

9. The construction method according to claim 8, wherein after the permeable pipe (4) is placed, an acid injection pipe (7) extending into the permeable pipe (4) is placed in the drilled hole (3), an inner end portion of the acid injection pipe (7) is located at a position where an upper portion of the permeable pipe (4) is close to the water stopping member (5), an inner end portion of the water discharge pipe (6) is located at a bottom portion of the permeable pipe (4), and then the solid packing material (8) is placed;

when acid solution is injected into the water permeable pipe (4), the acid solution is injected through the acid injection pipe (7), and liquid substances in the water permeable pipe (4) are extracted by the drain pipe (6) until the extracted substances are pure acid solution.

10. A method as claimed in claim 8, characterized in that, after the placement of the permeable pipe (4), a pressurizing capsule (9) is placed in the borehole (3), the pressurizing capsule (9) being connected to an outwardly extending pressurizing pipe (91);

and injecting fluid into the pressurizing bag body (9) through the pressurizing pipe (91) for pressurizing at the same time of injecting mortar.

11. The construction method according to claim 9 or 10, wherein after the solid filler (8) is dissolved, the acid injection tube (7) exposed from the dissolution tube is cut off, polyurethane is injected into the acid injection tube (7), and the acid injection tube (7) is closed;

after the solid filling material (8) is dissolved, the inflation tube (91) exposed from the dissolution tube is cut off, polyurethane is injected into the inflation tube (91), and the inflation tube (91) is closed.

12. The construction method according to any one of claims 8 to 10, wherein the injected acidic solution is an acetic acid solution.

13. The method of claim 12, wherein the acetic acid solution is heated and then injected into the water-permeable pipe (4).