Tunnel excavation test device and method

Abstract

The application discloses a tunnel excavation test device and method, and relates to the technical field of geotechnical engineering model test, which comprises a model box, at least one anti-freezing liquid bag and a plurality of freezing pipes. The model box can accommodate a test soil body. A water inlet is arranged at the bottom of the model box. The anti-freezing liquid bag and the freezing pipes are fixedly arranged in the model box. Any anti-freezing liquid bag is surrounded by a plurality of freezing pipes. The anti-freezing liquid bag and the freezing pipes are buried in the test soil body. The anti-freezing liquid bag can accommodate anti-freezing liquid. The anti-freezing liquid bag is in communication with the outside of the model box, so that the anti-freezing liquid in the anti-freezing liquid bag can be discharged to the outside of the model box. The freezing pipes are in communication with the outside of the model box, and the freezing pipes can transmit freezing liquid. The application can flexibly, truly and conveniently simulate artificial freezing stratum tunnel excavation and thawing stratum tunnel excavation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering model test, in particular to a tunnel excavation test device and method. BACKGROUND

[0002] Artificial freezing method is a kind of geotechnical engineering reinforcement technology that reduces the temperature of stratum through artificial refrigeration technology, freezes the water in soil to form a frozen soil curtain, thereby enhancing the mechanical properties of stratum and reducing the permeability. This method has significant advantages in tunnel engineering, especially in complex geological conditions such as water-rich sand layer and soft and broken zone. Artificial freezing method can effectively control stratum deformation during tunnel construction by forming a continuous frozen soil curtain, preventing engineering accidents such as collapse and water gushing, and significantly improving construction safety and engineering reliability.

[0003] In the field of tunnel engineering research, physical model test has been widely used as an important technical means to study the mechanical properties and deformation laws of tunnel surrounding rock. Existing tunnel model test devices mainly focus on shield excavation face stability analysis, three-dimensional deformation monitoring during tunnel construction, surrounding rock strength property research, and ground settlement prediction. However, there is currently a lack of test devices that can carry out both artificial freezing stratum tunnel excavation and thawing stratum tunnel excavation. SUMMARY

[0004] The purpose of the present application is to provide a tunnel excavation test device and method to solve the problems existing in the prior art, which can flexibly, realistically and conveniently control the simulation of artificial freezing stratum tunnel excavation and thawing stratum tunnel excavation.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] The present application provides a tunnel excavation test device, which comprises a model box, at least one anti-freezing liquid bag and a plurality of freezing pipes. The model box can accommodate test soil. The bottom of the model box is provided with a water inlet. The anti-freezing liquid bag and the freezing pipes are fixed in the model box. Any anti-freezing liquid bag is surrounded by a plurality of freezing pipes. The anti-freezing liquid bag and the freezing pipes are buried in the test soil. The anti-freezing liquid bag can accommodate anti-freezing liquid. The anti-freezing liquid bag can communicate with the outside of the model box, so that the anti-freezing liquid in the anti-freezing liquid bag can be discharged to the outside of the model box. The freezing pipes can communicate with the outside of the model box, and the freezing pipes can transmit frozen liquid.

[0007] Preferably, the model box comprises a box body, a front window and a rear window, the top end of the box body is open, the front panel of the box body is provided with a front window, the rear panel of the box body is provided with a rear window, the front window is sealingly and fixedly arranged on the front panel of the box body, the front window can block the front window, the rear window is sealingly and fixedly arranged on the rear panel of the box body, and the rear window can block the rear window; the front end of the anti-freezing liquid bag and the front end of the freezing tube are fixedly arranged on the front window, and the rear end of the anti-freezing liquid bag and the rear end of the freezing tube are fixedly arranged on the rear window.

[0008] Preferably, the inner side of the front window is flush with the inner side of the front panel of the box body, the front window is provided with a front tunnel hole and a plurality of front mounting holes, a front protruding end cover is sealingly and fixedly arranged around the front tunnel hole on the outer side of the front window, the front protruding end cover is provided with a front accommodating groove, the front accommodating groove is in communication with the front tunnel hole, and the front end of the anti-freezing liquid bag extends into the front accommodating groove; the front mounting holes correspond to the freezing tubes one by one, and the front end of the freezing tube is fixedly arranged in the front mounting hole; the inner side of the rear window is flush with the inner side of the rear panel of the box body, the rear window is provided with a rear tunnel hole and a plurality of rear mounting holes, a rear protruding end cover is sealingly and fixedly arranged around the rear tunnel hole on the outer side of the rear window, the rear protruding end cover is provided with a rear accommodating groove, the rear accommodating groove is in communication with the rear tunnel hole, and the rear end of the anti-freezing liquid bag extends into the rear accommodating groove; the rear mounting holes correspond to the freezing tubes one by one, and the rear end of the freezing tube is fixedly arranged in the rear mounting hole.

[0009] Preferably, a through pipe is further arranged, the rear protruding end cover is provided with a through hole, the first end of the through pipe is fixedly arranged on the rear end of the anti-freezing liquid bag, the inside of the through pipe is in communication with the inside of the anti-freezing liquid bag, the second end of the through pipe extends to the outside of the box body through the through hole, the through pipe and the through hole are sealingly and fixedly connected through threads, and the second end of the through pipe can be in communication with the outside of the box body.

[0010] Preferably, a flow meter and a valve are arranged on the second end of the through pipe, the flow meter can detect the flow of the anti-freezing liquid in the through pipe, and the valve can control the on-off of the through pipe.

[0011] Preferably, the through pipe is threadedly connected with the through hole; the front protruding end cover comprises a front cover plate and a front baffle ring, the front baffle ring is arranged between the front cover plate and the outer side surface of the front window, one end of the front baffle ring is communicated with the front tunnel hole, the front cover plate can block the other end of the front baffle ring, and the front cover plate, the front baffle ring and the front window are sealingly connected by bolts; the rear protruding end cover comprises a rear cover plate and a rear baffle ring, the rear baffle ring is arranged between the rear cover plate and the outer side surface of the rear window, one end of the rear baffle ring is communicated with the rear tunnel hole, the rear cover plate can block the other end of the rear baffle ring, and the rear cover plate, the rear baffle ring and the rear window are sealingly connected by bolts; the through hole is arranged on the rear cover plate.

[0012] Preferably, the front sealing ring, the front gasket ring, the rear sealing ring and the rear gasket ring are further arranged, the front annular baffle is fixedly arranged on the front panel of the box body and surrounds the front window, the front gasket ring is arranged between the front annular baffle and the outer side surface of the front window, so that the inner side surface of the front window is flush with the inner side surface of the front panel of the box body, the front window, the front gasket ring and the front annular baffle are connected by bolts, and the front sealing ring is fixedly arranged between the front window and the box body; the rear annular baffle is fixedly arranged on the rear panel of the box body and surrounds the rear window, the rear gasket ring is arranged between the rear annular baffle and the outer side surface of the rear window, so that the inner side surface of the rear window is flush with the inner side surface of the rear panel of the box body, the rear window, the rear gasket ring and the rear annular baffle are connected by bolts, and the rear sealing ring is fixedly arranged between the rear window and the box body.

[0013] Preferably, the flow divider, the flow combiner and the refrigeration unit are further arranged, the freezing pipe comprises an inner pipe and an outer pipe, a liquid outlet is arranged at a first end of the inner pipe, a liquid inlet is arranged at a second end of the inner pipe, the outer pipe is fixedly arranged outside the inner pipe, a flow gap is formed between the inner side wall of the outer pipe and the outer side wall of the inner pipe, a first end of the outer pipe is closed, the first end of the outer pipe is arranged at the liquid outlet, and a drainage port is arranged on the side wall of the outer pipe, so that the refrigerant enters the inner pipe from the liquid inlet, then enters the flow gap from the liquid outlet, and finally exits the outer pipe from the drainage port; the liquid supply port of the refrigeration unit is communicated with the flow divider, the flow divider is communicated with all the liquid inlets, the flow divider divides the refrigerant provided by the liquid supply port of the refrigeration unit into each liquid inlet; the liquid return port of the refrigeration unit is communicated with the flow combiner, the flow combiner is communicated with all the drainage ports, and the flow combiner combines the refrigerant flowing out of each drainage port into the liquid return port of the refrigeration unit.

[0014] Preferably, a plurality of displacement sensors, a plurality of pressure sensors and a plurality of temperature sensors are fixedly arranged in the model box, the displacement sensors are capable of detecting the displacement of the test soil body, the pressure sensors are capable of detecting the pressure of the test soil body, and the temperature sensors are capable of detecting the temperature of the test soil body; a smooth film is fixedly arranged on the inner side of the model box, and a lubricating liquid is applied on the surface of the smooth film close to the test soil body.

[0015] The application also provides a tunnel excavation test method, which uses the tunnel excavation test device as described above, and comprises the following steps:

[0016] Melting ground stratum tunnel excavation simulation: comprising the following steps:

[0017] S11: building the tunnel excavation test device;

[0018] S12: preparing the test soil body and filling the test soil body into the model box;

[0019] S13: injecting water into the model box through the water injection port;

[0020] S14: simulating tunnel excavation by discharging the anti-freezing liquid bag, and recording all monitoring data in the process of discharging the anti-freezing liquid bag;

[0021] Artificial freezing ground stratum tunnel excavation simulation: comprising the following steps:

[0022] S21: building the tunnel excavation test device;

[0023] S22: preparing the test soil body and filling the test soil body into the model box;

[0024] S23: injecting water into the model box through the water injection port;

[0025] S24: circulating the freezing liquid in the freezing pipe to freeze the water-containing soil body in the area where the freezing pipe is located;

[0026] S25: after the freezing wall is closed, simulating tunnel excavation by discharging the anti-freezing liquid bag, and recording all monitoring data in the process of discharging the anti-freezing liquid bag;

[0027] Local freezing failure ground stratum tunnel excavation simulation: comprising the following steps:

[0028] S31: building the tunnel excavation test device;

[0029] S32: preparing the test soil body and filling the test soil body into the model box;

[0030] S33: injecting water into the model box through the water injection port;

[0031] S34: freeze the soil in the area where the freezing pipe is located until the frozen wall of the area to be frozen is closed;

[0032] S35: After the soil layer enters the local frozen failure state, the tunnel excavation is simulated by discharging the antifreeze liquid bag, and all monitoring data during the discharge process of the antifreeze liquid bag are recorded.

[0033] The present application has the following technical effects relative to the prior art:

[0034] The tunnel excavation test device and method provided by the present application sets a model box to accommodate the test soil, sets an antifreeze liquid bag to accommodate antifreeze liquid, sets a freezing pipe to transmit frozen liquid, and any one antifreeze liquid bag is surrounded by several freezing pipes. The antifreeze liquid bag and the freezing pipe are both buried in the test soil. The excavation of the tunnel is simulated by discharging the antifreeze liquid in the antifreeze liquid bag to the outside of the model box, the simulation of the tunnel excavation disturbance is realized, the simulation of the tunnel excavation process of the frozen ground is more real and controllable by controlling the step-by-step discharge process of the antifreeze liquid bag, and in actual tests, the number, cross-sectional shape and size of the antifreeze liquid bag can be configured according to actual test requirements. The cross-sectional shape of the antifreeze liquid bag includes but is not limited to a circular shape, an elliptical shape and a horseshoe shape. Different cross-sectional types, different sizes and different numbers of antifreeze liquid bags are selected to realize different types of tunnel excavation simulation, simulate different tunnel section geometric characteristics such as cross-sectional shape, size and multi-chamber arrangement, flexibly, realistically and conveniently simulate the tunnel excavation of the artificial frozen ground under different section geometric characteristics and different freezing conditions, flexibly, realistically and conveniently simulate the tunnel excavation of the thawed ground under different section geometric characteristics and different groundwater level conditions, and realize the water and sand sealing during the entire excavation process. It is suitable for the tunnel excavation test of the frozen method of sand, clay and composite ground, provides a reliable test platform for the test research of the artificial frozen method tunnel construction, provides a reliable technical means for studying the tunnel excavation induced ground deformation law under different freezing conditions, can be used to simulate the tunnel excavation disturbance induced ground deformation law and stress distribution characteristics under different types of artificial frozen soil conditions, provides important technical support for the model test research of the frozen method construction, fills the gap in the prior art, and has important theoretical value and engineering significance for promoting the application of the artificial frozen method in tunnel engineering. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

[0036] Figure 1 A schematic view of the tunnel excavation test device provided by the present application;

[0037] Figure 2 A schematic view of the box in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the box in the tunnel excavation test device provided by the present application;

[0038] Figure 3 A schematic view of the rear window in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the rear window in the tunnel excavation test device provided by the present application;

[0039] Figure 4 A schematic view of the anti-freezing liquid bag in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the anti-freezing liquid bag in the tunnel excavation test device provided by the present application;

[0040] Figure 5 A schematic view of the rear cover plate in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the rear cover plate in the tunnel excavation test device provided by the present application;

[0041] Figure 6 A schematic view of the rear retaining ring in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the rear retaining ring in the tunnel excavation test device provided by the present application;

[0042] Figure 7 A schematic view of the front cover plate in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the front cover plate in the tunnel excavation test device provided by the present application;

[0043] Figure 8 A schematic view of the front retaining ring in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the front retaining ring in the tunnel excavation test device provided by the present application;

[0044] Figure 9 A schematic view of the freezing pipe in the tunnel excavation test device provided by the present application; Figure 1 A schematic view of the freezing pipe in the tunnel excavation test device provided by the present application;

[0045] In the drawings: 1 - model box, 2 - anti-freezing liquid bag, 3 - freezing pipe, 4 - front window, 5 - rear window, 6 - rear convex end cover, 7 - through pipe, 8 - flow meter, 9 - valve, 10 - through hole, 11 - front cover plate, 12 - front retaining ring, 13 - rear cover plate, 14 - rear retaining ring, 15 - rear annular baffle, 16 - water injection port, 17 - inner pipe, 18 - outer pipe, 19 - liquid outlet, 20 - liquid inlet, 21 - flow gap, 22 - drainage port. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] The purpose of the present invention is to provide a tunnel excavation test device and method to solve the problems existing in the above-mentioned prior art, which can flexibly, realistically and easily controllably simulate tunnel excavation in artificial frozen strata and tunnel excavation in thawed strata.

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] like Figures 1 to 9 As shown, this embodiment provides a tunnel excavation test device, including a model box 1, at least one antifreeze liquid bag 2 and a plurality of freezing pipes 3. The model box 1 can accommodate test soil. A water inlet 16 is provided at the bottom of the model box 1. The antifreeze liquid bag 2 and the freezing pipes 3 are fixedly arranged in the model box 1. Any antifreeze liquid bag 2 is surrounded by a plurality of freezing pipes 3. The antifreeze liquid bag 2 and the freezing pipes 3 are buried in the test soil. The antifreeze liquid bag 2 can accommodate antifreeze liquid. The antifreeze liquid bag 2 can be connected to the outside of the model box 1 so that the antifreeze liquid in the antifreeze liquid bag 2 can be discharged to the outside of the model box 1. The freezing pipes 3 can be connected to the outside of the model box 1 and the freezing pipes 3 can transmit the freezing liquid.

[0051] The tunnel excavation test device provided in this embodiment is provided with a model box 1 to accommodate the test soil, an antifreeze liquid bag 2 to accommodate the antifreeze liquid, and a freezing pipe 3 to transmit the freezing liquid, and any antifreeze liquid bag 2 is surrounded by a number of freezing pipes 3, and the antifreeze liquid bag 2 and the freezing pipe 3 are all buried in the test soil. The antifreeze liquid in the antifreeze liquid bag 2 is discharged to the outside of the model box 1 to simulate the excavation of the tunnel, thereby realizing the simulation of the tunnel excavation disturbance. By controlling the step-by-step drainage process of the antifreeze liquid bag 2, the simulation of the tunnel excavation process of the frozen stratum is made more realistic and controllable. In actual testing, the number, cross-sectional shape and size of the antifreeze liquid bag 2 can be configured according to actual test requirements. The cross-sectional shape of the antifreeze liquid bag 2 includes but is not limited to circular, elliptical and horseshoe-shaped. By selecting antifreeze liquid bags 2 of different cross-sectional types, different sizes and different numbers, different types of tunnel excavation simulations can be realized, and the cross-sectional shape, size and multi-chamber layout can be simulated. Different tunnel cross-sectional geometric characteristics can flexibly, realistically and easily simulate the excavation of tunnels in artificial frozen strata with different cross-sectional geometric characteristics and different freezing conditions. It can also flexibly, realistically and easily simulate the excavation of tunnels in thawed strata with different cross-sectional geometric characteristics and different groundwater levels, and can achieve water and sand sealing during the entire excavation process. It is suitable for freezing tunnel excavation tests in sandy soil, clay and composite strata, providing a reliable test platform for experimental research on tunnel construction using artificial freezing method, and providing reliable technical means for studying the deformation law of strata induced by tunnel excavation under different freezing conditions. It can be used to simulate the deformation law and stress distribution characteristics of strata induced by tunnel excavation disturbance under different types of artificial frozen soil conditions, providing important technical support for model test research on freezing method construction, which will fill the existing technical gap and have important theoretical value and engineering significance for promoting the application of artificial freezing method in tunnel engineering.

[0052] As a more preferred implementation of this embodiment, the model box 1 includes a box body, a front window 4 and a rear window 5. The top of the box body is open, a front window is provided on the front panel of the box body, and a rear window is provided on the rear panel of the box body. The front window 4 is sealed and fixed on the front panel of the box body, and the front window 4 can block the front window. The rear window 5 is sealed and fixed on the rear panel of the box body, and the rear window 5 can block the rear window. The front end of the antifreeze liquid capsule 2 and the front end of the freezing pipe 3 are fixed on the front window 4, and the rear end of the antifreeze liquid capsule 2 and the rear end of the freezing pipe 3 are fixed on the front window 4. They are all fixed on the rear view window 5, and the front view window 4 and the rear view window 5 are both made of transparent material to facilitate observation of the internal situation of the box; as a more preferred implementation method of this embodiment, the box is a rectangular steel box composed of steel plates and square steels welded and bolted together, and the webs are welded on the outside of each panel of the box to increase the rigidity of the box and resist lateral deformation. An open and close water injection port 16 is reserved at the bottom of the left and right side panels of the box for installing a water injection valve to carry out water inlet and outlet of the box. The front view window 4 and the rear view window 5 can be made of but not limited to transparent materials such as organic glass.

[0053] As a more preferred embodiment of the present embodiment, the inner side of the front window 4 is flush with the inner side of the front panel of the box body, a front tunnel hole and a plurality of front mounting holes are formed on the front window 4, a front protruding end cover is sealingly and fixedly arranged around the front tunnel hole on the outer side of the front window 4, a front accommodating groove is formed on the front protruding end cover, the front accommodating groove is in communication with the front tunnel hole, and the front end of the anti-freezing liquid bag 2 extends into the front accommodating groove; the inner side of the rear window 5 is flush with the inner side of the rear panel of the box body, a rear tunnel hole and a plurality of rear mounting holes are formed on the rear window 5, a rear protruding end cover 6 is sealingly and fixedly arranged around the rear tunnel hole on the outer side of the rear window 5, a rear accommodating groove is formed on the rear protruding end cover 6, the rear accommodating groove is in communication with the rear tunnel hole, and the rear end of the anti-freezing liquid bag 2 extends into the rear accommodating groove, thereby achieving effective water sealing and fixing of the front end of the anti-freezing liquid bag 2 and the rear end of the anti-freezing liquid bag 2, providing reliable protection for the simulated freezing method construction and different underground water level soil melting excavation test; the structure of the front tunnel hole, the front protruding end cover, the rear tunnel hole and the rear protruding end cover 6 can be flexibly adjusted according to the test requirements, so as to adapt to the position, number, cross-sectional shape and size of the anti-freezing liquid bag 2, and then the matching of different positions, different numbers, different cross-sectional shapes and different sizes of the anti-freezing liquid bag 2 can be completed by replacing different front windows 4 and different rear windows 5; the front mounting hole corresponds to the freezing pipe 3 one by one, the front end of the freezing pipe 3 is fixedly arranged in the front mounting hole, the rear mounting hole corresponds to the freezing pipe 3 one by one, and the rear end of the freezing pipe 3 is fixedly arranged in the rear mounting hole, so as to realize the installation of the freezing pipe 3, wherein the outer wall of the freezing pipe 3 needs to be sealingly matched with the inner wall of the front mounting hole and the inner wall of the rear mounting hole, the arrangement of the freezing pipe 3, the front mounting hole and the rear mounting hole, including the arrangement distance, diameter and arrangement mode, can be adjusted according to the size, shape, position and number of the prototype tunnel, so as to realize the stratum freezing according to the test requirements.

[0054] As a more preferred embodiment of the present embodiment, the tunnel excavation test device provided by the present embodiment further comprises a through pipe 7, a through hole 10 is formed on the rear protruding end cover 6, the first end of the through pipe 7 is fixedly arranged on the rear end of the anti-freezing liquid bag 2, the inside of the through pipe 7 is in communication with the inside of the anti-freezing liquid bag 2, the second end of the through pipe 7 passes through the through hole 10 and extends to the outside of the box body, the through pipe 7 is sealingly and fixedly connected with the through hole 10 through threads, and the second end of the through pipe 7 can be in communication with the outside of the box body, thereby achieving simple structure, easy manufacturing and use.

[0055] As a more preferred embodiment of the present embodiment, the second end of the through pipe 7 is provided with a flow meter 8 and a valve 9, the flow meter 8 can detect the flow of the anti-freezing liquid in the through pipe 7, and the valve 9 can control the on-off of the through pipe 7, and the flow meter 8 and the valve 9 are preferably detachable.

[0056] As a more preferred embodiment of the present embodiment, the through pipe 7 is threadedly connected with the through hole 10, which can effectively avoid water leakage at the connection between the through pipe 7 and the through hole 10, and plays a good water sealing effect; the front protruding end cover includes a front cover plate 11 and a front blocking ring 12, the front blocking ring 12 is arranged between the outer side surface of the front cover plate 11 and the front window 4, one end of the front blocking ring 12 is in communication with the front tunnel hole, and the front cover plate 11 can block the other end of the front blocking ring 12; the front cover plate 11, the front blocking ring 12 and the front window 4 are sealingly connected by bolts, which can effectively avoid water leakage at the connection between the front cover plate 11, the front blocking ring 12 and the front window 4, and plays a good water sealing effect; the rear protruding end cover 6 includes a rear cover plate 13 and a rear blocking ring 14, the rear blocking ring 14 is arranged between the outer side surface of the rear cover plate 13 and the rear window 5, one end of the rear blocking ring 14 is in communication with the rear tunnel hole, and the rear cover plate 13 can block the other end of the rear blocking ring 14; the rear cover plate 13, the rear blocking ring 14 and the rear window 5 are sealingly connected by bolts, which can effectively avoid water leakage at the connection between the rear cover plate 13, the rear blocking ring 14 and the rear window 5, and plays a good water sealing effect; the through hole 10 is formed in the rear cover plate 13; as a more preferred embodiment of the present embodiment, the front cover plate 11, the front blocking ring 12, the rear cover plate 13 and the rear blocking ring 14 are made of the same transparent material as the front window 4 and the rear window 5, which facilitates observation during the test process.

[0057] As a more preferred embodiment of the present embodiment, the tunnel excavation test device further includes a front sealing ring, a front gasket ring, a rear sealing ring and a rear gasket ring, a front annular baffle is fixedly arranged on the front panel of the box body around the front window, the front gasket ring is arranged between the outer side surface of the front annular baffle and the front window 4, so that the inner side surface of the front window 4 is flush with the inner side surface of the front panel of the box body, the front window 4, the front gasket ring and the front annular baffle are bolted, and the front sealing ring is fixedly arranged between the front window 4 and the box body, which can effectively avoid water leakage at the connection between the front window 4 and the box body, and plays a good water sealing effect; a rear annular baffle 15 is fixedly arranged on the rear panel of the box body around the rear window, the rear gasket ring is arranged between the outer side surface of the rear annular baffle 15 and the rear window 5, so that the inner side surface of the rear window 5 is flush with the inner side surface of the rear panel of the box body, the rear window 5, the rear gasket ring and the rear annular baffle 15 are bolted, and the rear sealing ring is fixedly arranged between the rear window 5 and the box body, which can effectively avoid water leakage at the connection between the rear window 5 and the box body, and plays a good water sealing effect.

[0058] As a more preferred embodiment of the present embodiment, the tunnel excavation test device provided by the present embodiment further comprises a flow divider, a flow combiner and a refrigeration unit. The freezing pipe 3 comprises an inner pipe 17 and an outer pipe 18. The first end of the inner pipe 17 is provided with a liquid outlet 19. The second end of the inner pipe 17 is provided with a liquid inlet 20. The outer pipe 18 is fixedly sleeved on the outer side of the inner pipe 17. The inner side wall of the outer pipe 18 and the outer side wall of the inner pipe 17 are provided with a flow gap 21. The first end of the outer pipe 18 is closed and is arranged at the liquid outlet 19. The side wall of the outer pipe 18 is provided with a drainage port 22. The refrigerant flows into the inner pipe 17 through the liquid inlet 20, then flows into the flow gap 21 through the liquid outlet 19, and finally flows out of the outer pipe 18 through the drainage port 22. The liquid outlet of the refrigeration unit is in communication with the flow divider. The flow divider is in communication with all the liquid inlets 20. The flow divider divides the refrigerant provided by the liquid outlet of the refrigeration unit into each liquid inlet 20. The liquid return port of the refrigeration unit is in communication with the flow combiner. The flow combiner is in communication with all the drainage ports 22. The flow combiner combines the refrigerant flowing out of each drainage port 22 into the liquid return port of the refrigeration unit. The refrigerant is circulated between the refrigeration unit and the freezing pipe 3, so as to facilitate the effective water sealing of the model box 1.

[0059] As a more preferred embodiment of the present embodiment, the tunnel excavation test device provided by the present embodiment further comprises a plurality of displacement sensors, a plurality of pressure sensors and a plurality of temperature sensors. The displacement sensors, the pressure sensors and the temperature sensors are fixedly arranged in the model box 1. The displacement sensors can detect the soil displacement inside the test soil body. The pressure sensors can detect the soil pressure inside the test soil body. The temperature sensors can detect the soil temperature inside the test soil body, so as to detect the soil condition inside the test soil body. A smooth film is fixedly arranged on the inner side of the model box 1. The surface of the smooth film close to the test soil body is coated with lubricating liquid, which can effectively reduce the boundary effect caused by friction. As a more preferred embodiment of the present embodiment, the smooth film is made of polystyrene film, which is convenient to make and use.

[0060] Embodiment two

[0061] The present embodiment provides a tunnel excavation test method using the tunnel excavation test device in embodiment one, which comprises the following steps:

[0062] Melting ground stratum tunnel excavation simulation: comprising the following steps:

[0063] S11: building a tunnel excavation test device;

[0064] S12: preparing a test soil body and filling the test soil body into the model box 1;

[0065] S13: injecting water into the model box 1 through the water injection port 16;

[0066] S14: Simulate tunnel excavation by draining the anti-freezing liquid bag 2, and record all monitoring data during the process of draining the anti-freezing liquid bag 2;

[0067] Artificially frozen ground tunnel excavation simulation: including the following steps:

[0068] S21: Build a tunnel excavation test device;

[0069] S22: Prepare the test soil, and fill the test soil into the model box 1;

[0070] S23: Inject water into the model box 1 through the water injection port 16;

[0071] S24: Circulate the refrigerant in the freezing pipe 3 to freeze the water-containing soil in the area where the freezing pipe 3 is located;

[0072] S25: After the freezing wall is closed, simulate tunnel excavation by draining the anti-freezing liquid bag 2, and record all monitoring data during the process of draining the anti-freezing liquid bag 2;

[0073] Partial freezing failure ground tunnel excavation simulation: including the following steps:

[0074] S31: Build a tunnel excavation test device;

[0075] S32: Prepare the test soil, and fill the test soil into the model box 1;

[0076] S33: Inject water into the model box 1 through the water injection port 16;

[0077] S34: Close the circulating cold bath at the freezing failure simulation position or remove the freezing pipe 3, simulate the state of partial freezing failure ground, circulate the refrigerant in the remaining freezing pipes 3 to freeze the water-containing soil in the area where the freezing pipe 3 is located, until the freezing wall of the required freezing area is closed;

[0078] S35: After the soil layer enters the state of partial freezing failure, simulate tunnel excavation by draining the anti-freezing liquid bag 2, and record all monitoring data during the process of draining the anti-freezing liquid bag 2.

[0079] The tunnel excavation test method provided by the embodiment is characterized in that the model box 1 is arranged to accommodate the test soil body, the anti-freezing liquid bag 2 is arranged to accommodate the anti-freezing liquid, the freezing pipe 3 is arranged to accommodate the freezing liquid, and any one of the anti-freezing liquid bags 2 is surrounded by a plurality of freezing pipes 3, the anti-freezing liquid bag 2 and the freezing pipe 3 are both buried in the test soil body, the anti-freezing liquid in the anti-freezing liquid bag 2 is discharged to the outside of the model box 1 to simulate the excavation of the tunnel, the simulation of the tunnel excavation disturbance is realized, the step-by-step liquid discharge process of the anti-freezing liquid bag 2 is controlled, the simulation of the tunnel excavation process of the frozen stratum is more real and controllable, and in actual tests, the number, cross-sectional shape and size of the anti-freezing liquid bag 2 can be configured according to actual test requirements, the cross-sectional shape of the anti-freezing liquid bag 2 includes but is not limited to a circular shape, an elliptical shape and a horseshoe shape, different types of prototype tunnel excavation simulations are realized by selecting anti-freezing liquid bags 2 of different cross-sectional types, different sizes and different numbers, different tunnel section geometric characteristics such as the cross-sectional shape, size and multi-chamber arrangement can be simulated, the tunnel excavation can be flexibly, truly and conveniently simulated, and the water and sand sealing in the whole excavation process can be realized, the method is suitable for the tunnel excavation test of the freezing method in sandy soil, clay and composite stratum, provides a reliable test platform for the test research of the artificial freezing method tunnel construction, provides a reliable technical means for studying the stratum deformation law induced by the tunnel excavation under different freezing conditions, can be used to simulate the stratum deformation law and stress distribution characteristics induced by the tunnel excavation disturbance under different types of artificial frozen soil layer conditions, provides important technical support for the model test research of the freezing method construction of underground engineering, fills the gap in the prior art, and has important theoretical value and engineering significance for promoting the application of the artificial freezing method in tunnel engineering.

[0080] As a more preferred embodiment of the embodiment, in S11, S21 and S31, a smooth film is fixedly laid on the inner side of the model box 1, and a lubricating liquid is applied to the surface of the smooth film close to the test soil body, so that the boundary effect caused by the friction force can be effectively reduced, and the clarity of the front window 4 and the rear window 5 after multiple tests can be ensured; in S12, S22 and S32, when the test soil body is prepared, similar materials are prepared, the similar materials are mixed according to the similar ratio, so that the test soil body can simulate the physical properties of the actual soil layer, the test soil body is filled into the model box 1 to simulate the actual soil layer, and displacement sensors, pressure sensors and temperature sensors are installed to monitor the soil conditions inside the test soil body in real time; in S13, water is injected into the model box 1 through the water injection port 16, and the water level is controlled to simulate different underground water levels; in S24, the temperature sensor monitors the soil temperature in real time, and the freezing liquid is low-temperature silicon oil; in S25, after the freezing circle is formed, when the thickness of the freezing wall meets the design value of the test, the anti-freezing liquid bag 2 is used to simulate the tunnel excavation; in S34, the temperature sensor monitors the soil temperature in real time, and the freezing liquid is low-temperature silicon oil.

[0081] The tunnel excavation test device in the embodiment one is suitable for various geotechnical model tests, and the test effect of the tunnel excavation test device in the embodiment one depends on the specific test type, the tunnel excavation test method provided in the embodiment provides general operation steps suitable for various model tests, and the multifunctionality of the tunnel excavation test device in the embodiment one, the feasibility of the partial freezing application and the feasibility of the freezing failure simulation are highlighted.

[0082] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above embodiment description is only used for helping to understand the method and the core idea of the present application; meanwhile, for the general technical personnel in the field, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A tunnel excavation test device, characterized in that: The invention comprises a model box, at least one antifreeze liquid bag and a plurality of freezing pipes, wherein the model box can accommodate a test soil body, a water injection port is provided at the bottom of the model box, the antifreeze liquid bag and the freezing pipes are fixedly arranged in the model box, any one of the antifreeze liquid bags is surrounded by a plurality of freezing pipes, and a plurality of freezing pipes form a circle around the antifreeze liquid bag, the antifreeze liquid bag and the freezing pipes are buried in the test soil body, the antifreeze liquid bag can accommodate antifreeze liquid, the antifreeze liquid bag can be communicated with the outside of the model box so that the antifreeze liquid in the antifreeze liquid bag can be discharged to the outside of the model box, the freezing pipes can be communicated with the outside of the model box, and the freezing pipes can transmit the freezing liquid; The model box includes a box body, a front viewing window and a rear viewing window. The top of the box body is open, the front panel of the box body is provided with a front window, the rear panel of the box body is provided with a rear window, the front viewing window is sealed and fixed to the front panel of the box body, the front viewing window can block the front window, the rear viewing window is sealed and fixed to the rear panel of the box body, and the rear viewing window can block the rear window; the front end of the antifreeze liquid bag and the front end of the freezing pipe are both fixed on the front viewing window, and the rear end of the antifreeze liquid bag and the rear end of the freezing pipe are both fixed on the rear viewing window; The front viewing window is provided with a front tunnel hole, and a front protruding end cover is sealed and fixedly provided on the outer side of the front viewing window around the front tunnel hole, and a front accommodating groove is provided on the front protruding end cover, and the front accommodating groove is communicated with the front tunnel hole, and the front end of the antifreeze liquid bag extends into the front accommodating groove; the rear viewing window is provided with a rear tunnel hole, and a rear protruding end cover is sealed and fixedly provided on the outer side of the rear viewing window around the rear tunnel hole, and a rear accommodating groove is provided on the rear protruding end cover, and the rear accommodating groove is communicated with the rear tunnel hole, and the rear end of the antifreeze liquid bag extends into the rear accommodating groove.

2. The tunnel excavation test device according to claim 1, characterized in that: The inner side surface of the front window is flush with the inner side surface of the front panel of the box body, and a plurality of front mounting holes are provided on the front window, and the front mounting holes correspond to the freezing pipes one-to-one, and the front end of the freezing pipe is fixed in the front mounting holes; the inner side surface of the rear window is flush with the inner side surface of the rear panel of the box body, and a plurality of rear mounting holes are provided on the rear window, and the rear mounting holes correspond to the freezing pipes one-to-one, and the rear end of the freezing pipe is fixed in the rear mounting holes.

3. The tunnel excavation test device according to claim 2, characterized in that: It also includes a through tube, a through hole is opened on the rear protruding end cover, the first end of the through tube is fixedly arranged on the rear end of the antifreeze liquid bag, the interior of the through tube is communicated with the interior of the antifreeze liquid bag, the second end of the through tube passes through the through hole and extends to the outside of the box, the through tube and the through hole are fixedly connected by a threaded seal, and the second end of the through tube can be communicated with the outside of the box.

4. The tunnel excavation test device according to claim 3, characterized in that: A flow meter and a valve are provided on the second end of the through-tube. The flow meter can detect the flow of the antifreeze liquid in the through-tube, and the valve can control the on-off of the through-tube.

5. The tunnel excavation test device according to claim 3, characterized in that: The through tube is threadedly connected to the through hole; the front protruding end cover includes a front cover plate and a front baffle ring, the front baffle ring is placed between the front cover plate and the outer side surface of the front window, one end of the front baffle ring is communicated with the front tunnel hole, the front cover plate can block the other end of the front baffle ring, the front cover plate, the front baffle ring and the front window are sealed and connected by bolts; the rear protruding end cover includes a rear cover plate and a rear baffle ring, the rear baffle ring is placed between the rear cover plate and the outer side surface of the rear window, one end of the rear baffle ring is communicated with the rear tunnel hole, the rear cover plate can block the other end of the rear baffle ring, the rear cover plate, the rear baffle ring and the rear window are sealed and connected by bolts; the through hole is opened on the rear cover plate.

6. The tunnel excavation test device according to claim 2, characterized in that: The cam is secured to the front of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the latch is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, and the cam is secured to the rear of the box body by means of a latch, 7. The tunnel excavation test device according to claim 1, characterized in that: It also includes a flow divider, a flow combiner and a refrigeration unit, the freezing pipe includes an inner pipe and an outer pipe, the first end of the inner pipe is provided with a liquid outlet, the second end of the inner pipe is provided with a liquid inlet, the outer pipe is fixedly sleeved outside the inner pipe, a flow gap is left between the inner side wall of the outer pipe and the outer side wall of the inner pipe, the first end of the outer pipe is closed, the first end of the outer pipe is placed at the liquid outlet, a drainage port is provided on the side wall of the outer pipe, so that the refrigerant enters the inner pipe from the liquid inlet, and then flows out from the inner pipe. The liquid outlet enters the flow gap and finally leaves the outer tube from the drainage port; the liquid supply port of the refrigeration unit is connected with the diverter, and the diverter is connected with all the liquid inlets, and the diverter diverts the refrigerant provided by the liquid supply port of the refrigeration unit into each of the liquid inlets; the return liquid port of the refrigeration unit is connected with the merger, and the merger is connected with all the drainage ports, and the merger merges the refrigerant flowing out of each of the drainage ports into the return liquid port of the refrigeration unit.

8. The tunnel excavation test device according to claim 1, characterized in that: It also includes several displacement sensors, several pressure sensors and several temperature sensors, which are all fixedly arranged in the model box. The displacement sensor can detect the soil displacement inside the test soil body, the pressure sensor can detect the soil pressure inside the test soil body, and the temperature sensor can detect the soil temperature inside the test soil body. A smooth film is fixedly laid on the inner side of the model box, and a lubricating liquid is applied to the surface of the smooth film close to the test soil body.

9. A tunnel excavation test method using the tunnel excavation test apparatus according to any one of claims 1 to 8, characterized in that: include: Tunnel excavation simulation in thawing soil: includes the following steps: S11: Set up tunnel excavation test equipment; S12: Prepare the test soil and fill the test soil into the model box; S13: injecting water into the model box through the water injection port; S14: simulate tunnel excavation by draining the antifreeze liquid bag and record all monitoring data during the antifreeze liquid bag drainage process; Simulation of tunnel excavation in artificially frozen ground: includes the following steps: S21: Set up tunnel excavation test equipment; S22: Prepare the test soil and fill the test soil into the model box; S23: injecting water into the model box through the water injection port; S24: circulating a refrigerant in the freezing pipe to freeze the water-containing soil in the area where the freezing pipe is located; S25: After the freezing wall is closed, the antifreeze liquid bag is drained to simulate tunnel excavation, and all monitoring data during the antifreeze liquid bag drainage process are recorded; Tunnel excavation simulation in partially frozen failure strata includes the following steps: S31: Set up tunnel excavation test equipment; S32: Prepare the test soil and fill the test soil into the model box; S33: injecting water into the model box through the water injection port; S34: closing the circulating cold bath or removing the freezing pipe at the freezing failure simulation location to simulate the local freezing failure ground state, and circulating the freezing liquid in the remaining freezing pipes to freeze the water-bearing soil in the area where the freezing pipes are located until the freezing wall of the area to be frozen is completed; S35: After the soil layer enters a state of partial freezing failure, tunnel excavation is simulated by draining the antifreeze liquid bag, and all monitoring data during the antifreeze liquid bag drainage process are recorded.

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