Testing device for simulating cohesive force of tunnel passing through stratified rock mass

Abstract

A testing device for simulating cohesive force of a tunnel passing through a layered rock mass comprises the layered rock mass formed by mutually stacked rock slices, the layered rock mass is inserted into a mounting groove of a rock mass mounting frame, the rock mass mounting frame is placed in a grouting model device, and the grouting model device is matched with a water injection device, a grouting device and a grouting reinforcement effect device; the grouting model device comprises a box body formed by hermetically connecting steel plates; the water injection device comprises a height-adjustable water tank; the grouting device comprises a grouting steel pipe drilled into the stratified rock mass, and grouting openings arrayed in the axial direction are formed in the grouting steel pipe in the radial direction. The stratified rock mass is installed through the rock mass installation frame, and the cohesive force and the internal friction angle of the stratified rock mass after grouting under the real water pressure environment are simulated and obtained in the grouting model device.

Description

Technical Field

[0001] The utility model relates to the field of underground engineering disaster prevention and control, and particularly relates to a cohesive force testing device for simulating tunnel crossing through layered rock masses. Background Technique

[0002] Crossing through poor geological bodies and formation structural interfaces usually becomes a controlling project for submarine tunnel construction, directly affecting construction safety. If not properly handled, it will induce disasters and lead to project failure. In order to achieve the stability control of layered rock masses in poor geological sections, grouting reinforcement technology has been widely applied worldwide, playing an important role in ensuring project safety and quality, and also strongly promoting the continuous progress and rapid development of underwater tunnel and water formation tunnel construction technologies. During the tunnel construction process, the cohesive force between rock layers of layered rock masses will change due to the influence of tunnel opening. In order to avoid collapse, it is extremely important to measure the cohesive force between layered rock masses.

[0003] Layered rock mass is a very widely distributed rock mass type in the world. Due to experiencing various geological tectonic actions during the formation process, layered rock mass has significant differences compared with other rock masses, and there are bedding structures such as bedding planes and schistosity planes that are oriented and layered. In order to study the stability problem of surrounding rock in layered rock mass tunnels, scholars mostly use indoor model tests, theoretical modeling, numerical simulation, on-site monitoring and measurement, and inverse analysis, etc., to comprehensively and systematically study the failure mechanism of layered rock mass, surrounding rock stability, etc. The strength of rock mass is affected by bedding planes. For different rock masses, the degree of influence of bedding planes on them varies greatly. Even for the same kind of rock, its mechanical properties will also vary due to the influence of various factors.

[0004] On the other hand, layered rock masses widely exist in tunnel engineering. The long-term geological history evolution process and tectonic movement make their physical and mechanical properties tend to be complicated. Many domestic and foreign scholars have deeply studied the constitutive model and mechanical parameters of layered rock masses through experimental or numerical simulation methods, etc. Most of the research is physical simulation tests, and there is a lack of research on the cohesive force and internal friction angle of rock mass structural planes with different bedding angles, different numbers and sizes of circular holes, etc.

[0005] Therefore, there is an urgent need for a cohesive force testing device for simulating tunnel crossing through layered rock masses to simulate the influence of tunnel hole size and quantity on the cohesive force and internal friction angle of the structural plane of layered rock masses. Content of the Utility Model

[0006] The purpose of the present utility model is to provide, in view of the defects and deficiencies of the prior art, a cohesion test device for simulating the grouting path planning and reinforcement of layered rock masses under the action of different water pressures, and capable of accurately evaluating the grouting reinforcement effect in a simulated tunnel passing through a layered rock mass, and finally realizing the acquisition of performance data on the influence of different tunnel hole sizes and quantities on the cohesion and internal friction angle of the horizontal or inclined structural plane of the layered rock mass.

[0007] To achieve the above purpose, the present utility model provides a cohesion test device for simulating a tunnel passing through a layered rock mass, which includes a layered rock mass composed of mutually stacked rock slices. The layered rock mass is inserted into the installation groove of a rock mass installation frame, and the rock mass installation frame is placed in a grouting model device. The grouting model device is equipped with a water injection device, a grouting device, and a grouting reinforcement effect device; the grouting model device includes a box body formed by airtight connection of steel plates. The box body is provided with a transparent grouting observation board, a grouting hole, and a water outlet hole; the water injection device includes a water tank with adjustable height. The water tank is connected to the box body through a water injection pipe to form different groundwater pressures on the layered rock mass; the grouting device includes a grouting steel pipe drilled into the layered rock mass. The grouting steel pipe is radially provided with grouting ports arranged along the axial direction. After grouting is completed, the layered rock mass is taken out for testing to obtain the cohesion between the rock slices. The cohesion test device for simulating a tunnel passing through a layered rock mass of the present utility model uses a water injection device to simulate the stress environment of the underground layered rock mass, truly restoring the construction site environment. Through the grouting model device and the grouting device, the on-site grouting situation is simulated. According to the grouting reinforcement effect device, an almost real grouting effect is obtained. After grouting is completed, the layered rock mass is taken out for testing to obtain the cohesion between the rock slices, so as to judge the influence of the tunnel hole size and quantity on the cohesion and internal friction angle of the structural plane of the layered rock mass. The present utility model installs the layered rock mass through the rock mass installation frame, and simulates and obtains the cohesion and internal friction angle of the layered rock mass after grouting under a real water pressure environment in the grouting model device.

[0008] The box body is formed by airtight connection of steel plates to each other. The top of the box body is provided with a top plate, and the top plate is provided with a water injection port. The steel plates on the side of the box body are provided with a grouting hole and a water outlet hole arranged up and down. A transparent grouting observation board is arranged between the grouting hole and the water outlet hole, which is convenient for observing the grouting effect of the grouting slurry.

[0009] The water tank is connected to a chain block, and the chain block drives the water tank to move up and down to simulate the formation of a groundwater system environment with different water pressures.

[0010] The grouting steel pipe is connected to an air pump and a first grouting pump in a first grouting barrel through a first grouting pipe. The first grouting pipe is connected to a second grouting pipe, and the second grouting pipe is connected to an air pump and a second grouting pump in a second grouting barrel.

[0011] A first stirrer is arranged in the first grouting barrel, and a second stirrer is arranged in the second grouting barrel, which are used for uniformly mixing the grouting slurry.

[0012] The grouting model device is connected with a monitoring device. The monitoring device includes sensors, and the sensors include stress gauges, strain gauges, flow meters and pressure monitors. The stress gauges are placed in the grouting model device, the strain gauges are pasted on the inner wall of the box body, the flow meters are placed on the pipelines connected to the water injection pipes, grouting steel pipes and water outlet holes, and the pressure monitors are placed in the first grouting pipe. The monitoring device realizes the stress and stress change conditions of the layered rock mass in the grouting model device, has the flow change conditions of pressure, water injection and grouting, and realizes the restoration of the water vapor content change conditions of the layered rock mass in the underground environment where it occurs, providing accurate data support for the grouting work at the actual site.

[0013] The water injection port and the water injection pipe are sealed with epoxy resin AB glue, and the grouting hole and the grouting steel pipe are sealed with epoxy resin AB glue to prevent the leakage of water and grouting slurry.

[0014] The grouting reinforcement effect device includes a grouting effect observation pipe with zero grouting pressure. The internal part of the grouting effect observation pipe is embedded with a layered rock mass. The porosity of the embedded layered rock mass only allows the grouting slurry to enter. The grouting effect is judged in real time according to the concentration of the grouting slurry flowing out of the grouting effect observation pipe.

[0015] Adopting the above technical solution, the cohesion test device for simulating a tunnel crossing a layered rock mass forms a layered rock mass composed of mutually stacked rock slices. The layered rock mass is inserted into the installation groove of the rock mass installation frame of the tunnel. Through the grouting model device, the water injection device simulates the water content and water head of the layered rock mass under different water pressures at the construction site, restores the construction layered rock mass environment, grouts the layered rock mass through the grouting steel pipe by the grouting device, and evaluates the grouting effect through the grouting reinforcement effect device. At the same time, the monitoring device obtains the best grouting parameters, and finally detects the cohesion and internal friction angle between the rock slices of the target grouted rock mass with different parameters, providing accurate data support for the actual tunnel crossing the layered rock mass. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] FIG. 1 is a schematic structural diagram of a cohesion test device for simulating a tunnel crossing a layered rock mass according to the present invention;

[0018] FIG. 2 is a schematic structural diagram of the installation of the grouting steel pipe in the present invention;

[0019] FIG. 3 is a schematic structural diagram of the grouting model device in the present invention;

[0020] Figure 4 is a schematic diagram of the rock mass installation frame structure in the utility model;

[0021] Figure 5 is a schematic diagram of the layered rock mass structure of the horizontally inserted rock mass installation frame in the utility model;

[0022] Figure 6 is a schematic diagram of the layered rock mass structure of the inclined inserted rock mass installation frame in the utility model. Specific embodiments

[0023] Next, in combination with the drawings in the embodiments of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0024] Such as Figures 1-6 A cohesion test device for simulating tunnel crossing through layered rock mass includes a layered rock mass composed of mutually laminated rock flakes. The layered rock mass is inserted into the installation groove 73 of the rock mass installation frame, and the rock mass installation frame is placed in the grouting model device, and the grouting model device is equipped with a water injection device, a grouting device, and a grouting reinforcement effect device.

[0025] The grouting model device includes a box body 10 formed by hermetically connecting steel plates. The box body 10 is provided with a transparent grouting observation board 5, a grouting hole 26, and a water outlet hole 25. The top of the box body is provided with a top plate 30, and the top plate is provided with a water injection port 24. The steel plates on the side of the box body are provided with a grouting hole 26 and a water outlet hole 25 arranged up and down, and a transparent grouting observation board 5 is arranged between the grouting hole and the water outlet hole.

[0026] The water injection device 14 includes a water tank 16 with adjustable height. The water tank 16 is connected to the box body 10 through a water injection pipe 13 to form different groundwater pressures on the layered rock mass. The water tank 16 is connected to a chain hoist 15, and the chain hoist 15 drives the water tank 16 to move up and down to realize the change of water pressure.

[0027] The grouting device includes a grouting steel pipe 22 drilled into the layered rock mass. The grouting steel pipe 22 is radially provided with grouting ports 52 arranged along the axial direction. After grouting is completed, the layered rock mass is taken out for detection to obtain the cohesion between the rock flakes. The grouting steel pipe 22 is connected to an air pump 1 and a first grouting pump 2 in a first grouting bucket 3 through a first grouting pipe 21. The first grouting pipe 21 is connected to a second grouting pipe 20, and the second grouting pipe 20 is connected to the air pump 1 and a second grouting pump 17 in a second grouting bucket 18 to increase the grouting flow rate, or can be connected to different grouting steel pipes to realize the grouting performance at multiple points. In order to increase the uniformity of the grouting slurry, a first stirrer 4 is arranged in the first grouting bucket 3, and a second stirrer 19 is arranged in the second grouting bucket 18.

[0028] As a preferred structure monitoring device 7 includes sensors, the sensors include a stress gauge, a strain gauge, a flow velocity meter and a pressure monitor; the stress gauge is placed in the grouting model device, the strain gauge is pasted on the inner wall of the box body 10, the flow velocity meter is placed on the pipeline connecting the water injection pipe, the grouting steel pipe 22 and the water outlet hole 25, and the pressure monitor is placed in the first grouting pipe 21. The monitoring device 7 monitors the grouting parameters in real time through the induction wire 6 connecting the sensors, and the grouting parameters at least include grouting pressure and flow rate.

[0029] The grouting reinforcement effect device includes a grouting effect observation pipe with zero grouting pressure. The grouting effect observation pipe is embedded in the rock mass, and the porosity of the embedded rock mass is limited to the entry of the grouting slurry. The grouting effect is judged in real time according to the concentration of the grouting slurry flowing out of the grouting effect observation pipe.

[0030] To improve the airtight performance of the box body 10, the water injection port 24 and the water injection pipe 13 are sealed with epoxy resin AB glue, and the grouting hole 26 and the grouting steel pipe 22 are sealed with epoxy resin AB glue.

[0031] As a specific implementation, the platform size of the box body 10 is 1000mm * 1000mm * 1000mm. The box body 10 is made of 10mm thick steel plate, which can meet the requirement of the maximum grouting pressure of 10Mpa. The side and bottom are connected by high-strength bolts. To ensure the airtightness of the model box, the joints are sealed with 2mm thick rubber gaskets and sealant. Transparent grouting observation plates with different heights are arranged on the sides, made of high-strength organic glass. The organic glass is 225mm * 100mm, and the bottom of the organic glass is 225mm, 450mm, 675mm, and 900mm away from the bottom of the box body 10 in sequence. A water injection port with a radius of 20mm is reserved at the top of the box body 10, and a water outlet hole with a radius of 5mm is reserved at the bottom. After the rock mass sample is placed in the box body, the top plate 30 is embedded at the open mouth of the box body for sealing, and the joints are sealed with thick rubber pads and sealant.

[0032] As for the specific installation process of the layered rock mass composed of mutually stacked rock flakes, it is as follows:

[0033] Step 1: Sampling. The size of this rock mass installation frame 70 is 150mm * 150mm * 150mm. The left and right sides of the rock mass installation frame 70 device are steel bars, and there are equidistant installation grooves 73 around the front and rear steel bars 71. The upper side is surrounded by steel bars, the center position is empty, and the lower side is steel bars. Bolts 72 with gaskets are used to fix the eight corners of the rock mass installation frame 70, which is convenient for the disassembly of the layered rock mass.

[0034] Step 2: Drill a plurality of circular holes with different sizes and quantities at regular intervals on each layered rock mass, and the inclination angles are 0° and 45°.

[0035] Step 3: Insert the layered rock mass with drilled round holes into the installation groove 73 layer by layer. Respectively set the horizontally inserted layered rock mass 81, set the first round hole 82, or set the inclined inserted layered rock mass 83, set the second round hole 84, and complete the specific installation of the layered rock mass composed of overlapping rock flakes.

[0036] The utility model simulates the different cohesive forces and internal friction angles of the structural planes of the tunnel passing through the layered rock mass by adjusting the size and quantity of the holes, and solves the problems of complex processing and difficult production of standard rock specimens in the existing test for measuring the cohesive force and internal friction angle of layered rocks.

[0037] The specific grouting steps in the grouting device are as follows:

[0038] ① First, drill two vertically parallel grouting steel pipes and a grouting effect observation pipe with zero grouting pressure in the layered rock mass. The two vertically parallel grouting steel pipes are the grouting steel pipe 22 and the first grouting steel pipe 23 respectively. The first grouting holes 44 with equal intervals are arranged on the first grouting steel pipe 23, and the grouting ports 52 with equal intervals are arranged on the grouting steel pipe 22. The grouting steel pipe 22 and the first grouting steel pipe 23 are matched with the first round hole 82 or the second round hole 84.

[0039] ② The grouting holes of each grouting steel pipe are symmetrically distributed vertically, and the interval between adjacent holes is adjusted according to the situation in a timely manner;

[0040] ③ The grouting pressure of the grouting steel pipe is greater than the water pressure of the occurrence environment; for the grouting effect observation pipe with zero grouting pressure, the grouting effect observation pipe is internally embedded in the layered rock mass, and the porosity of the embedded layered rock mass is limited to the entry of the grouting slurry. The grouting effect is judged in real time according to the concentration of the grouting slurry flowing out of the grouting effect observation pipe.

[0041] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present utility model without departing from the principle and purpose of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A cohesion test device for simulating tunneling through layered rock mass, characterized in that: The invention comprises a layered rock mass composed of mutually stacked rock slices, the layered rock mass is inserted into a mounting groove (73) of a rock mass mounting frame (70), the rock mass mounting frame is placed in a grouting model device, and the grouting model device is equipped with a water injection device, a grouting device, and a grouting reinforcement effect device; the grouting model device comprises a box body (10) formed by a sealed connection of steel plates, the box body (10) is provided with a transparent grouting observation plate (5), a grouting hole (26), and a water outlet hole (25); the water injection device (14) comprises a water tank (16) with adjustable height, the water tank (16) is connected to the water tank (16) through a water injection pipe ( 13) The connecting box (10) forms different underground water pressures on the layered rock mass; the grouting device comprises a grouting steel pipe (22) drilled into the layered rock mass, the grouting steel pipe (22) radially opens grouting ports (52) arranged along the axial direction, the grouting steel pipe (22) is connected to the air pump (1) and the first grouting pump (2) in the first grouting barrel (3) through the first grouting pipe (21), the first grouting pipe (21) is connected to the second grouting pipe (20), and the second grouting pipe (20) is connected to the air pump (1) and the second grouting pump (17) in the second grouting barrel (18).

2. The cohesion test device for simulating tunneling through layered rock mass according to claim 1, characterized in that: The box body (10) is provided with a top plate (30) on the top plate, which is provided with a water injection port (24); a steel plate on the side of the box body is provided with grouting holes (26) and water outlet holes (25) arranged up and down; and a transparent grouting observation plate (5) is provided between the grouting holes and the water outlet holes.

3. The cohesion test device for simulating tunneling through layered rock mass according to claim 1, characterized in that: The water tank (16) is connected to the chain hoist (15), and the chain hoist (15) drives the water tank (16) to move up and down.

4. The cohesion test device for simulating tunnel passing through layered rock mass according to claim 1, characterized in that: A first mixer (4) is provided in the first grouting bucket (3), and a second mixer (19) is provided in the second grouting bucket (18).

5. The cohesion testing device for simulating tunnel passing through layered rock mass according to claim 1, characterized in that: The grouting model device is connected to a monitoring device (7), the monitoring device (7) comprising a sensor, the sensor comprising a stress gauge, a strain gauge, a flow meter and a pressure monitoring gauge; the stress gauge is placed in the grouting model device, the strain gauge is adhered to the inner wall of the box (10), the flow meter is placed in the pipeline connecting the water injection pipe, the grouting steel pipe (22) and the water outlet (25), and the pressure monitoring gauge is placed in the first grouting pipe (21).

6. The cohesion test device for simulating tunneling through layered rock mass according to claim 1, characterized in that: The water injection port (24) and the water injection pipe (13) are sealed by epoxy resin AB glue, and the grouting hole (26) and the grouting steel pipe (22) are sealed by epoxy resin AB glue.

7. The cohesion testing device for simulating tunneling through layered rock mass according to claim 1, characterized in that: The grouting reinforcement effect device comprises a grouting effect observation tube with zero grouting pressure, wherein the grouting effect observation tube is embedded with layered rock mass, and the porosity of the embedded layered rock mass is limited to the entry of grouting slurry. The concentration of the grouting slurry flowing out of the grouting effect observation tube is used to judge the grouting effect in real time.

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