Water-rich region fractured rock mass tunnel lining water pressure distribution test simulation system
Technical Field
The invention relates to the field of tunnel stress simulation, in particular to a tunnel lining water pressure simulation system.
Background
According to the needs of development strategies in China, the requirements for traffic infrastructure are increasing day by day, the perfection of railway and road networks is the key point in traffic infrastructure, and the perfection of the road networks is required to inevitably build a large number of mountain tunnels. Particularly, in western regions of China, mountains are formed, geological structures are complex, abundant underground water brings technical problems for building tunnels, and particularly, when large buried tunnels are built in cracked mountains, linings often need to bear high water pressure, which is very unfavorable for tunnel structures. In order to reduce the water pressure of the lining, a water control scheme of 'mainly blocking and discharging in limited quantity' is mainly adopted at present, and the water pressure of the lining can be effectively reduced while the local ecological environment is not influenced. In areas with high water pressure and rich water, the construction of tunnels is very difficult, and the constructed tunnels are frequently damaged due to the deformation, cracking, damage and the like of lining structures in operation, and the main reason is that the tunnel linings bear higher water pressure. Under the water control scheme of 'mainly blocking and discharging in limited quantity', the tunnel structure is necessarily influenced by underground water, so that the experimental study on the water pressure distribution characteristics at the back of the lining under high water pressure is particularly important.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a water pressure distribution test simulation system for the fractured rock mass tunnel lining in the water-rich area, which accurately simulates the real seepage environment of the fractured rock mass tunnel lining in the water-rich area and is convenient for testing and analyzing the water pressure distribution characteristics at the back of the lining, on the fracture surface and in the surrounding rock.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a water-rich region fractured rock mass tunnel lining water pressure distribution test simulation system comprises a cuboid model box, wherein a polypropylene pipe penetrating through two opposite side walls of the model box and having one end closed and one end open is arranged at the lower part of the model box, a water quantity measuring device is arranged at the lower part of the open end of the polypropylene pipe, water drainage holes are arranged on the outer circumference of the polypropylene pipe, a longitudinal blind pipe and a circumferential blind pipe which are communicated with the inside of the polypropylene pipe are arranged outside the circumference of the polypropylene pipe in the model box, geotechnical cloth and a pore water pressure gauge for simulating fractures are arranged in a sealing box, the pore water pressure gauge is connected with a static strain gauge connected to a computer, cuboid surrounding rocks of a simulated rock mass poured by cement mortar are arranged around the polypropylene pipe, the longitudinal blind pipe, the circumferential blind pipe and the geotechnical cloth, a sealing top cover is arranged at the top of the model box, and a water inlet and a, the top cover is further provided with a pressure gauge for measuring water pressure of the inner top surface of the model box, and the bottom of the model box is provided with a drainage valve for simulating a permeable boundary of the bottom surface of the tunnel.
The technical scheme of the invention is further improved as follows: the vertical blind pipe is arranged at the bottoms of two sides of the polypropylene pipe along the length direction of the polypropylene pipe, the circumferential blind pipe is arranged along the outer circumference of the polypropylene pipe, the circumferential blind pipe is communicated with the vertical blind pipe, the vertical blind pipe is communicated with the polypropylene pipe, the vertical blind pipe and the circumferential blind pipe respectively comprise an inner spring, and gauze is wrapped outside the spring.
The technical scheme of the invention is further improved as follows: the water inlet is connected with a pressure water source through a high-pressure water pipe, a valve a is arranged at the water inlet, a valve b is arranged at the pressure water source, a branch water outlet pipe is further arranged on the high-pressure water pipe, and a valve c is arranged on the branch water outlet pipe.
The technical scheme of the invention is further improved as follows: and a valve d communicated with the interior of the model box is arranged on the top cover.
The technical scheme of the invention is further improved as follows: the geotechnical cloth is arranged according to the content of a simulation test, one geotechnical cloth is arranged in parallel according to the length direction vertical to the polypropylene pipe when a through crack is simulated, three sections parallel to the geotechnical cloth are cut, namely a section a, a section c at two ends and a section b in the middle, the section b is superposed with the geotechnical cloth, the section a passes through the annular blind pipe, and the pore water pressure gauge is arranged on the section a, the section b and the section c in the middle;
two sides of the geotextile are arranged in parallel according to the length direction of the polypropylene pipe in parallel when two parallel through cracks are simulated, three sections parallel to the geotextile are cut, namely a section A at two ends, a section C and a middle section B, the section A and the section C are coincided with the geotextile, the section A and the section C pass through the circumferential blind pipe, and the pore water pressure gauge is arranged on the section A, the section C and the middle section B.
The technical scheme of the invention is further improved as follows: a plurality of pore water pressure gauges are arranged on the section b, the section A and the section C around the circumference of the polypropylene pipe, and three vertical-row pore water pressure gauges are arranged on the section b, the section A and the section C in parallel with the diameter direction of the polypropylene pipe; and a vertical pore water pressure gauge is arranged on the section a, the section c and the section B along the radial direction of the polypropylene pipe.
The technical scheme of the invention is further improved as follows: the polypropylene pipe is externally wrapped with gauze, and the pore water pressure gauge is externally wrapped with gauze.
The technical scheme of the invention is further improved as follows: and a wire outlet for leading out a signal wire of the pore water pressure gauge is arranged on the model box.
The technical scheme of the invention is further improved as follows: the top of the surrounding rock is lower than the bottom surface of the top cover.
The technical scheme of the invention is further improved as follows: the drainage valves are arranged in a plurality and are uniformly distributed on two crossed diagonal lines on the bottom surface of the model box.
Due to the adoption of the technical scheme, the invention has the technical progress that:
the invention is convenient for analyzing the water pressure distribution characteristics at the back of the lining, on the crack surface and in the surrounding rock by accurately simulating the real seepage environment of the water-rich region fractured rock mass tunnel lining.
The longitudinal blind pipe and the circumferential blind pipe are simulated by spring-wrapped gauze, and the drainage system is manufactured by wrapping the gauze on the spring, so that the smoothness of the drainage system can be effectively ensured. The pore water pressure gauge is wrapped by gauze, so that the situation that the mortar blocks the permeable stones pre-buried on the pore water pressure gauge in the surrounding rock in the process of simulating the pouring of the surrounding rock is avoided.
The stability of water pressure and seepage in the model box is realized by the matching adjustment of the valve b and the valve groove c; the valve d on the top cover communicates the external air with the interior of the model box, so that the effect of stabilizing the air pressure in the model box is achieved, and the water source in the model box is conveniently injected and filled.
The arrangement of the pore water pressure gauge in the simulation box ensures that the water pressure at the back of the lining, on the crack surface and in the surrounding rock is completely obtained, and provides complete and comprehensive data support for the test result.
The drainage valves are arranged on the bottom surface of the model box in a plurality of uniform distribution mode, drainage at the bottom of the tunnel is controlled, and seepage fields of surrounding rocks under different water permeable boundary conditions are simulated by controlling the opening and closing of the drainage valves.
Drawings
FIG. 1 is a schematic diagram of the system architecture of the present invention;
FIG. 2 is a schematic view of a through-fracture configuration of the present invention;
FIG. 3 is a schematic view of a structure of two parallel through-cuts according to the present invention;
FIG. 4 is a schematic diagram of pore water pressure gauge arrangements at section b, section A and section C;
FIG. 5 is a schematic diagram of pore water pressure gauge arrangements at section a, section c and section B;
the device comprises a model box 1, a model box 2, a polypropylene pipe 3, a longitudinal blind pipe 4, a circumferential blind pipe 5, geotextile 6, a pore water pressure gauge 7, surrounding rock 8, a top cover 9, a pressure gauge 10, a wire outlet 11, a high-pressure water pipe 12, valves a and 13, valves b and 14, a branch water outlet pipe 15, valves c and 16, valves d and 17, a wire outlet 18 and a water drainage hole.
Detailed Description
The present invention will be described in further detail with reference to the following examples:
as shown in fig. 1-5, the water-rich region fractured rock mass tunnel lining water pressure distribution test simulation system comprises a cuboid model box 1, a polypropylene pipe 2 penetrating two opposite side walls of the model box 1 is arranged at the middle lower part of the model box 1, one end of the polypropylene pipe 2 is opened and the other end is closed, a water outlet 18 is arranged on the outer circumference of the polypropylene pipe 2, one row of the water outlet 18 is arranged along the length direction of the polypropylene pipe 2, a water quantity measuring device is arranged at the lower part of the opening end of the polypropylene pipe 2, the water quantity measuring device mainly comprises a measuring cylinder, a measuring cup and the like, and a stop. The polypropylene pipe 2 is wrapped with gauze, and the gauze wrapped on the polypropylene pipe simulates the underground water seepage of the geotextile and the waterproof plate layer between the secondary lining and the primary support of the tunnel. The circumference of the polypropylene pipe 2 is externally provided with a longitudinal blind pipe 3 and a circumferential blind pipe 4, the longitudinal blind pipe 3 is arranged at the positions, close to the bottom, of the two sides of the polypropylene pipe 2 along the length direction of the polypropylene pipe 2, the circumferential blind pipe 4 is arranged in a plurality along the outer circumference of the polypropylene pipe 2, the circumferential blind pipe 4 is communicated with the longitudinal blind pipe 3, and the longitudinal blind pipe 3 is communicated with the polypropylene pipe 2. The longitudinal blind pipe 3 and the annular blind pipe 4 both comprise internal springs, and gauze is wrapped outside the springs. Specifically, the tunnel lining is simulated by using a polypropylene pipe with the outer diameter of 20cm, the longitudinal blind pipe is simulated by using spring-wrapped gauze with the outer diameter of 4mm, and the circumferential blind pipe is simulated by using spring-wrapped gauze with the outer diameter of 2 mm.
The sealing box 1 is internally provided with geotechnical cloth 5 and a pore water pressure gauge 6, wherein the geotechnical cloth 5 is used for simulating cracks and is arranged at the position where the cracks need to be simulated. The pore water pressure gauge 6 is connected with a static strain gauge which is connected with a computer, and a wire outlet 10 for leading out a signal wire of the pore water pressure gauge 6 is arranged on the model box 1. Cement mortar is poured around the polypropylene pipe 2, the longitudinal blind pipe 3, the annular blind pipe 4 and the geotextile 5 to form a cuboid surrounding rock 7 simulating a rock body.
A sealing top cover 8 is arranged at the top of the model box 1, and the top of the surrounding rock 7 is lower than the bottom surface of the top cover 8. The top cover 8 is provided with a water inlet and a pressure regulating valve for providing pressure water for the model box 1, the upper end of the water inlet is connected with a pressure water source through a high-pressure water pipe 11, the pressure regulating valve mainly comprises a valve b13 and a valve c15, wherein the valve b13 is arranged at the pressure water source, the high-pressure water pipe 11 is also provided with a branch water outlet pipe 14, the valve c15 is arranged on the branch water outlet pipe 14, and the stability of the water pressure and seepage flow in the model box is realized through the matching regulation of the valve b and the valve groove c. Wherein a valve a12 is arranged at the water inlet of the high-pressure water pipe 11 and plays a role of opening and closing the model box. Wherein the top cover 8 is provided with a valve d16 communicated with the interior of the model box 1, the valve d communicates the outside air with the interior of the model box, and the valve d plays a role in stabilizing the air pressure in the model box and is convenient for the injection and the filling of a water source in the model box.
The top cover 8 is also provided with a pressure gauge 9 for measuring the water pressure of the top surface of the top of the surrounding rock in the model box 1, and the pressure gauge is used for monitoring the water pressure in the model box. The bottom of the model box 1 is provided with a plurality of drainage valves which are uniformly distributed on two diagonal cross lines of the bottom surface of the model box 1 to control the drainage of the tunnel bottom, and the seepage field of the surrounding rock under different water permeable boundary conditions is simulated by controlling the opening and closing of the drainage valves.
The geotechnical cloth 5 is arranged according to the content of a simulation test, one geotechnical cloth 5 is arranged in parallel according to the length direction vertical to the polypropylene pipe 2 when a through crack is simulated, three sections parallel to the geotechnical cloth 5 are cut, namely a section a at two ends, a section c and a section b in the middle, the section b is superposed with the geotechnical cloth 5, and the section a passes through the annular blind pipe 4; a plurality of pore water pressure gauges 6 are arranged on the section b around the circumference of the polypropylene pipe, three vertical pore water pressure gauges 6 are radially arranged on the section b in parallel with the polypropylene pipe 2, wherein one vertical pore water pressure gauge 6 in the middle is radially superposed with the polypropylene pipe, and one vertical pore water pressure gauge 6 is radially arranged on the sections a and c along the polypropylene pipe.
When simulating two parallel through cracks, two sides of the geotextile 5 are arranged in parallel according to the length direction of the polypropylene pipe 2, three sections parallel to the geotextile 5 are cut, namely a section A at two ends, a section C and a section B in the middle, the section A and the section C are coincided with the geotextile 5, and the section A and the section C pass through the annular directional pipe 4. A plurality of pore water pressure meters 6 are arranged on the section A and the section C around the circumference of the polypropylene pipe, three vertical pore water pressure meters 6 are radially arranged on the section A and the section C in parallel to the polypropylene pipe 2, wherein one vertical pore water pressure meter 6 in the middle radially coincides with the polypropylene pipe 2, and one vertical pore water pressure meter 6 is radially arranged on the section B along the polypropylene pipe. The gauze is preferably wrapped outside the pore water pressure gauge 6, so that the sand pulp is prevented from blocking the permeable stones pre-embedded on the pore water pressure gauge in the surrounding rock in the pouring process of the surrounding rock. And each pore water pressure gauge 6 is numbered, thereby being convenient for measurement.