CN111425250A - Double-layer pressure-reducing water-proof and drainage system for karst water-rich tunnel and construction method of double-layer pressure-reducing water-proof and drainage system - Google Patents

Abstract

The invention provides a double-layer decompression, prevention and drainage system for a karst water-rich tunnel and a construction method thereof. The system is arranged between the primary branch of the tunnel and the second lining, and includes an outer drainage layer, a decompression layer, an inner drainage layer and a drainage channel. . Among them, the outer drainage layer includes outer longitudinal drainage blind pipes, outer circumferential drainage blind pipes, and permeable geotextiles; the decompression layer includes three-dimensional two-way geocells, sprayed porous lightweight aggregate permeable concrete and vertical connection pipes of the inner and outer drainage blind pipes The inner drainage layer includes inner longitudinal drainage blind pipe, inner circumferential drainage blind pipe, construction joint water stop strip and permeable geotextile; the drainage channel adopts distributed cluster drainage pipe to expand the traditional drainage pipe channel. The invention aims to solve the high water pressure and large flow waterproofing and drainage requirements of the karst water-rich tunnel in the rainy season by expanding the water storage capacity, reducing the water head pressure and improving the drainage efficiency.

Description

A double-layer decompression and drainage system for karst water-rich tunnel and its construction method

technical field

The invention relates to a waterproof and drainage structure for a tunnel in a karst water-rich stratum and a construction method thereof. It belongs to the field of tunnel design and construction.

Background technique

Leakage water is the most common disease in operating tunnels. Tunnel seepage water not only accelerates the aging of the tunnel structure, shortens the service life of the tunnel structure, but also increases the cost of tunnel operation and maintenance, and threatens the safety of the tunnel. The "Code for Design of Highway Tunnels" stipulates: "When the tunnel adopts composite lining, waterproof boards and non-woven fabrics should be set between the primary support and the secondary lining, and the waterproof boards should be made of easily welded waterproof membranes with a thickness of not less than 1.0mm; blind pipes should be installed along the back of the lining, with a longitudinal spacing of not more than 20m”. The traditional drainage system of the tunnel controls the drainage volume through blind pipes and drainage pipes, and its implementation method can only guarantee the drainage flow in the conventional groundwater level occurrence area.

The area of karst development area in my country is close to 1/3 of the country's land area, and the disease problem of karst tunnels is particularly serious. Among them, the main source of karst tunnel diseases is karst groundwater. On the one hand, the erosiveness of karst groundwater is harmful to the tunnel lining structure and drainage system. On the other hand, karst groundwater is closely related to surface hydrology. The sudden surge makes the traditional waterproof and drainage structure design unable to meet the drainage demand of the instantaneous large amount of water in the rainy season, and even the lining structure bears high external water pressure, which endangers the safety of the tunnel structure, and even causes the tunnel structure to crack and cause water leakage, which seriously affects the safety of the tunnel. operation. Therefore, in view of the differences in seasonal waterproofing and drainage requirements of karst water-rich tunnels, it has become an urgent scientific and engineering problem to develop a new type of waterproofing and drainage system structure that can adapt to different seasonal drainage requirements.

SUMMARY OF THE INVENTION

Technical problem: The purpose of the present invention is to provide a double-layer decompression and drainage system for karst water-rich tunnels and a construction method thereof. The new waterproof and drainage structure can meet the needs of different drainage volumes in different seasons, and can increase the drainage volume elastically and reduce the amount of water in the tunnel. The external water pressure weakens the impact of sudden rainfall surges on the lining structure.

Technical scheme: a double-layer decompression and drainage system for a karst water-rich tunnel of the present invention includes an outer drainage layer, a decompression layer, an inner drainage layer and a drainage channel between the initial support of the tunnel and the secondary lining, and the outer drainage layer is provided. Including the outer longitudinal drainage blind pipe, the outer circumferential drainage blind pipe, and the permeable geotextile; the decompression layer includes the three-dimensional two-way geocell, the sprayed porous light aggregate permeable concrete and the vertical connecting pipe of the inner and outer drainage blind pipes; the inner measurement drainage layer It includes inner longitudinal drainage blind pipe, inner circumferential drainage blind pipe and permeable geotextile; the drainage channel adopts distributed cluster drainage pipe at the junction of the secondary lining side wall and the bottom plate to expand the traditional drainage pipe channel.

in:

For the outer drainage layer, at the initial stage of the tunnel, the outer circumferential drainage blind pipes are arranged around the tunnel section at equal intervals along the tunnel axis direction, and the outer longitudinal drainage blind pipes are arranged along the tunnel axis direction. At the side wall and arch foot, finally lay a layer of permeable geotextile on the tunnel wall.

For the decompression layer, a three-dimensional two-way geocell is laid on the permeable geotextile, and the connecting pipe of the inner and outer drainage blind pipes is installed perpendicular to the initial support wall of the tunnel at the intersection of the outer circumferential drainage blind pipe and the outer longitudinal drainage blind pipe. Finally, the porous lightweight aggregate permeable concrete is sprayed in the three-dimensional two-way geocell, and the thickness of the permeable concrete just reaches the height of the three-dimensional two-way geocell.

For the inner drainage layer, a layer of permeable geotextile is laid on the surface of the permeable concrete, and then the inner circumferential drainage blind pipes and construction water stop strips are arranged at equal intervals along the tunnel axis direction according to the position of the connecting pipe. The secondary lining construction joints are aligned, and the inner circumferential drainage blind pipe is arranged in the middle of the adjacent construction waterstop; the longitudinal drainage blind pipe is connected between the circumferential drainage blind pipe and the waterstop, and the longitudinal drainage blind pipe is arranged in the tunnel arch. It is ensured that the intersection of the inner circumferential drainage dead pipe and the inner longitudinal drainage dead pipe is connected with the connecting pipe of the inner and outer drainage dead pipes.

For the drainage channel, after the reinforcement of the secondary lining structure is arranged and before the concrete is poured, distributed cluster drainage pipes are arranged in the concrete pouring local area where the traditional drainage pipes are originally arranged at the connection between the secondary lining side wall and the bottom plate of the tunnel, and the connection is made. The inner drainage layer and the drainage side ditch of the tunnel to expand the drainage channel of the traditional drainage pipe;

The construction method of the double-layer decompression and drainage system of the karst water-rich tunnel of the present invention comprises the following steps:

Step 1, close to the initial support structure of the tunnel, lay out the outer circumferential drainage dead pipe along the tunnel ring upward, and lay the outer longitudinal drainage dead pipe on the tunnel axis;

Step 2: Lay permeable geotextiles around the tunnel circumferential direction on the initial support structure, the outer circumferential drainage dead pipe and the outer longitudinal drainage dead pipe to cover the tunnel circumferential wall;

Step 3, install and fix the three-dimensional two-way geocell on the permeable geotextile to cover the permeable geotextile;

Step 4: At the intersection of the outer annular drainage dead pipe and the outer longitudinal drainage dead pipe, the connecting pipe of the inner and outer drainage dead pipes is arranged on the vertical tunnel wall, and fixed with a three-dimensional two-way geocell, and after the completion of step 5, the construction is in progress. Protection work that may cause blockage of the connecting pipe;

Step 5: Fill the interior of the three-dimensional two-way geocell with porous permeable concrete by means of spray pouring, so as to fill the entire cell;

Step 6, laying permeable geotextiles on the surface of the three-dimensional two-way geocell filled with porous permeable concrete;

In step 7, the inner circumferential drainage dead pipe and the inner longitudinal drainage dead pipe are arranged on the surface of the permeable geotextile in step 6. The position of the inner drainage layer dead pipe is parallel to the position of the outer drainage layer dead pipe, and the inner circumferential drainage dead pipe is placed. The intersection point with the inner longitudinal drainage dead pipe is connected with the connecting pipe of the inner and outer drainage dead pipes;

Step 8, applying the tunnel waterproof layer according to the conventional process;

Step 9, the reinforcement arrangement of the secondary lining structure is carried out on the outside of the waterproof layer;

Step 10: In the local area where the traditional drainage pipes are originally laid at the connection between the secondary lining side wall and the bottom plate of the tunnel, the distributed cluster drainage pipes are arranged in the gaps of the reinforcement mesh, and the distributed cluster drainage pipes are fixed by using the reinforcement mesh;

Step 11, pour the secondary lining concrete outside the waterproof layer.

Beneficial effects: The structure of the double-layer decompression and drainage system of the karst water-rich tunnel mainly includes setting an outer drainage layer, a decompression layer, an inner drainage layer and a drainage channel between the initial support of the tunnel and the secondary lining. The outer drainage layer is set close to the initial support of the tunnel, the outer drainage layer and the inner drainage layer are connected by connecting pipes, a decompression layer is arranged between the outer drainage layer and the inner drainage layer, and a waterproof layer is arranged between the inner drainage layer and the secondary lining . The main function of the outer drainage layer is to collect water from surrounding rock fissures, which plays a role in the conventional drainage of karst tunnels in dry season; the main function of the decompression layer is to expand the water storage capacity and reduce the head pressure, and the main function of the inner drainage layer is to collect the drainage of the decompression layer. The main function of the drainage channel is to increase the amount of water discharged into the drainage side ditch; the connecting pipes of the inner and outer drainage layers improve the drainage efficiency. The construction method of the invention is simple and effective, the functions of each drainage layer are clear, and the demand for large-flow drainage in the rainy season of the karst water-rich tunnel can be effectively guaranteed.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings and implementation cases.

Figure 1 is a schematic diagram of a double-layer decompression and drainage system;

In the above figure, there are: distributed cluster drainage pipe 1, inner longitudinal drainage blind pipe 2, outer longitudinal drainage blind pipe 3, outer annular drainage blind pipe 4, inner annular drainage blind pipe 5, the outer drainage layer and the inner drainage layer Connecting pipe 6 , three-dimensional two-way geocell 7 , porous permeable concrete 8 , initial support 9 , outer drainage layer 10 , decompression layer 11 , inner drainage layer 12 , waterproof layer 13 , secondary lining 14 .

Detailed ways

The following examples illustrate the technical scheme of the present invention in detail:

The double-layer decompression and drainage system of the karst water-rich tunnel of the present invention includes an outer drainage layer, a decompression layer, an inner drainage layer and a drainage channel arranged between the initial support of the tunnel and the secondary lining, and the outer drainage layer includes an outer longitudinal drainage blind Pipes (80mm single-wall perforated corrugated pipe, 5 tunnels on the top and side walls of the hole), outer annular drainage blind pipe (50mm single-wall perforated corrugated pipe, set at 12m circumferential interval), permeable geotextiles; the decompression layer includes three-dimensional Two-way geocell (cell height 50-100mm), sprayed porous lightweight aggregate permeable concrete (thickness 50-100mm and vertical connecting pipe of inner and outer drainage blind pipes (80mm single-wall corrugated pipe, length 50-100mm); inner drainage The layer includes inner longitudinal drainage blind pipes (80mm single-wall perforated corrugated pipes, 5 tunnels on the top side wall), inner circumferential drainage blind pipes (50mm single-wall perforated corrugated pipes, set at a circumferential interval of 12m) and permeable geotextiles ; Drainage is to use distributed cluster drainage pipes (a group of 10, the diameter of a single drainage pipe is 30mm) at the junction of the secondary lining side wall and the bottom plate to expand the traditional drainage pipe channel.

For the outer drainage layer, at the initial stage of the tunnel, the outer circumferential drainage blind pipes are arranged around the tunnel section at equal intervals along the tunnel axis direction, and the outer longitudinal drainage blind pipes are arranged along the tunnel axis direction. At the side wall and arch foot, the longitudinal drainage pipes are arranged symmetrically on both sides of the annular drainage pipe in a V-shaped arrangement, and the slope of the longitudinal drainage pipes is not less than 2%. Finally, a layer of permeable geotextile is laid on the tunnel wall.

For the decompression layer, a three-dimensional two-way geocell is laid on the permeable geotextile, and the connecting pipe of the inner and outer drainage blind pipes is installed perpendicular to the initial support wall of the tunnel at the intersection of the outer circumferential drainage blind pipe and the outer longitudinal drainage blind pipe. (80mm single-wall corrugated pipe, length 50-100mm), and finally spray porous lightweight aggregate permeable concrete (thickness 50-100mm) in the three-dimensional two-way geocell, and the thickness of the permeable concrete just reaches the height of the three-dimensional two-way geocell.

For the inner drainage layer, a layer of permeable geotextile is laid on the surface of the permeable concrete, and then the inner circumferential drainage blind pipes and construction water stop strips are arranged at equal intervals along the tunnel axis direction according to the position of the connecting pipe. The secondary lining construction joints are aligned, and the inner circumferential drainage blind pipe is arranged in the middle of the adjacent construction waterstop; the longitudinal drainage blind pipe is connected between the circumferential drainage blind pipe and the waterstop, and the longitudinal drainage blind pipe is arranged in the tunnel arch. It is ensured that the intersection of the inner circumferential drainage dead pipe and the inner longitudinal drainage dead pipe is connected with the connecting pipe of the inner and outer drainage dead pipes.

For the drainage channel, after the reinforcement of the secondary lining structure is arranged and before the concrete is poured, distributed cluster drainage pipes (one Group of 10, the diameter of a single drainage pipe is 30mm), connecting the inner drainage layer and the drainage side ditch of the tunnel to expand the drainage channel of the traditional drainage pipe;

Structure and construction method of double-layer decompression and drainage system for karst water-rich tunnel, including the following steps:

Step 1: Adhere to the initial support structure of the tunnel, lay out the outer annular drainage blind pipe along the tunnel ring upward, and arrange the outer longitudinal drainage blind pipe on the tunnel axis. The longitudinal drainage pipes are symmetrically arranged on both sides of the annular drainage pipe in a V shape. type layout, and the slope of the longitudinal drainage pipe is not less than 2%;

Step 2: Lay a permeable geotextile on the initial support structure, the outer circumferential drainage blind pipe and the outer longitudinal drainage blind pipe around the tunnel circumferential direction to cover the tunnel circumferential wall. Water stop strips are set between the pipes;

Step 3, install and fix a three-dimensional two-way geocell (cell height 50-100mm) on the permeable geotextile to cover the permeable geotextile;

Step 4: At the intersection of the outer annular drainage dead pipe and the outer longitudinal drainage dead pipe, the connecting pipe (80mm single-wall corrugated pipe, 50-100 mm long) of the inner and outer drainage dead pipes is set on the vertical tunnel wall, and three-dimensional two-way geotechnical The cell is fixed, and the protection work that may cause the blockage of the connecting pipe in the following step 5 is done well;

Step 5: Fill the interior of the three-dimensional two-way geocell with porous permeable concrete by means of spray pouring to fill the entire cell (thickness 50-100mm);

Step 6, laying permeable geotextiles on the surface of the three-dimensional two-way geocell filled with porous permeable concrete;

In step 7, the inner circumferential drainage dead pipe and the inner longitudinal drainage dead pipe are arranged on the surface of the permeable geotextile in step 6. The position of the inner drainage layer dead pipe is parallel to the position of the outer drainage layer dead pipe, and the inner circumferential drainage dead pipe is placed. The intersection point with the inner longitudinal drainage dead pipe is connected with the connecting pipe of the inner and outer drainage dead pipes;

Step 8, applying the tunnel waterproof layer according to the conventional process;

Step 9, the reinforcement arrangement of the secondary lining structure is carried out on the outside of the waterproof layer;

Step 10: In the local area where the traditional drainage pipes were originally laid at the connection between the secondary lining side wall and the bottom plate of the tunnel, the distributed cluster drainage pipes were arranged in the gaps of the reinforcement mesh, and the distributed cluster drainage pipes (a group of 10 A single drain pipe with a diameter of 30mm) is fixed;

Step 11, pour the secondary lining concrete outside the waterproof layer.

Claims (6)

1. The utility model provides a drainage system is prevented in double-deck decompression of rich water tunnel of karst which characterized in that: the method comprises the steps of arranging an outer side drainage layer, a decompression layer, an inner side drainage layer and a drainage channel between a tunnel primary support and a secondary lining, wherein the outer side drainage layer comprises an outer side longitudinal drainage blind pipe, an outer side circumferential drainage blind pipe and permeable geotextile; the pressure reduction layer comprises a three-dimensional bidirectional geocell, injection type porous lightweight aggregate permeable concrete and a vertical connecting pipe of an internal and external drainage blind pipe; the inner drainage layer comprises an inner longitudinal drainage blind pipe, an inner circumferential drainage blind pipe and a water-permeable geotextile; the drainage channel is formed by locally adopting distributed cluster drainage pipes at the joint of the secondary lining side wall and the bottom plate to enlarge the channel of the traditional drainage pipe.

2. The double-layer pressure-reducing water-proof and drainage system for the karst water-rich tunnel according to claim 1, wherein the outer drainage layers are characterized in that outer circumferential drainage blind pipes are arranged on the primary support surface of the tunnel at equal intervals along the axial direction of the tunnel around the section of the tunnel, outer longitudinal drainage blind pipes are arranged along the axial direction of the tunnel, and are respectively arranged at the arch part, the side wall and the arch foot of the tunnel, and finally a layer of permeable geotextile is laid on the wall surface of the tunnel.

3. The double-layer pressure-reducing, water-proof and drainage system for the karst water-rich tunnel according to claim 1, wherein the pressure-reducing layer is formed by laying three-dimensional bidirectional geocells on a permeable geotextile, connecting pipes of inner and outer drainage blind pipes are arranged at the intersection of an outer circumferential drainage blind pipe and an outer longitudinal drainage blind pipe and are perpendicular to the primary supporting wall surface of the tunnel, and finally porous light aggregate permeable concrete is sprayed in the three-dimensional bidirectional geocells, so that the thickness of the permeable concrete just reaches the height of the three-dimensional bidirectional geocells.

4. The double-layer pressure-reducing and water-preventing and draining system for the karst water-rich tunnel according to claim 1, wherein a layer of permeable geotextile is laid on the surface of the permeable concrete, inner annular drainage blind pipes and construction water stop bars are arranged at equal intervals along the axial direction of the tunnel according to the positions of the communicating pipes, the arrangement positions of the construction water stop bars are aligned with the construction joints of the secondary lining, and the inner annular drainage blind pipes are arranged in the middle of the adjacent construction water stop bars; the annular drainage blind pipes are connected with the water stop strips through longitudinal drainage blind pipes, the longitudinal drainage blind pipes are arranged at the arch parts, side walls and arch feet of the tunnels, and the junction of the inner annular drainage blind pipe and the inner longitudinal drainage blind pipe is connected with a connecting pipe of the inner drainage blind pipe and the outer drainage blind pipe.

5. The double-layer pressure-reducing and water-proof system for the karst water-rich tunnel according to claim 1, wherein the drainage channel is formed by arranging distributed bundled drainage pipes in a concrete pouring local area where conventional drainage pipes are originally arranged at the joint of the secondary lining side wall and the bottom plate of the tunnel after arranging reinforcing steel bars of the secondary lining structure and before pouring concrete, and connecting an inner drainage layer with a drainage side ditch of the tunnel to enlarge a drainage channel of the conventional drainage pipes.

6. The method for constructing the double-layer decompression waterproof and drainage system of the karst water-rich tunnel according to claim 1, characterized by comprising the following steps:

step 1, closely attaching to a tunnel primary support structure, arranging outer circumferential drainage blind pipes upwards along the circumferential direction of a tunnel, and arranging outer longitudinal drainage blind pipes on the axis of the tunnel;

step 2, paving permeable geotextile on the primary support structure, the outer circumferential drainage blind pipe and the outer longitudinal drainage blind pipe around the circumferential direction of the tunnel to cover the circumferential wall surface of the tunnel;

step 3, installing and fixing a three-dimensional bidirectional geocell on the permeable geotextile to cover the permeable geotextile;

step 4, arranging a connecting pipe of the inner and outer drainage blind pipes at the intersection point of the outer annular drainage blind pipe and the outer longitudinal drainage blind pipe, and fixing by using a three-dimensional bidirectional geocell, and performing protection work which can cause the blockage of the connecting pipe in the subsequent step 5;

step 5, filling porous pervious concrete in the three-dimensional bidirectional geocell by adopting a jet pouring mode to fill the whole geocell;

step 6, paving permeable geotextile on the surface of the three-dimensional bidirectional geocell filled with the porous permeable concrete;

step 7, laying an inner side circumferential drainage blind pipe and an inner side longitudinal drainage blind pipe on the surface of the permeable geotextile in the step 6, wherein the position of the inner side drainage layer blind pipe is parallel to that of the outer side drainage layer blind pipe, and connecting the intersection point of the inner side circumferential drainage blind pipe and the inner side longitudinal drainage blind pipe with a connecting pipe of the inner and outer drainage blind pipes;

step 8, constructing a tunnel waterproof layer according to a conventional process;

step 9, arranging reinforcing steel bars of a secondary lining structure on the outer side of the waterproof layer;

step 10, distributing distributed type cluster drainage pipes in a local area where traditional drainage pipes are originally distributed at the joint of the tunnel secondary lining side wall and the bottom plate by using reinforcing mesh arrangement gaps, and fixing the distributed type cluster drainage pipes by using the reinforcing mesh;

and 11, pouring secondary lining concrete outside the waterproof layer.

Images