Tunnel excavation support three-dimensional loading test system

Abstract

The invention provides a tunnel excavation support three-dimensional loading test system, belongs to the technical field of tunnel excavation experiment simulation, and aims to solve the problems that in the prior art, a simulation test is often carried out by simulating different stress conditions of stratums, and excavation simulation under more complex conditions is less. Comprising a frame, an extension bearing beam is arranged at the bottom of the frame, a test box and a rear-end counter-force beam are slidably connected to the extension bearing beam, a front-end counter-force beam is arranged on the side, away from the rear-end counter-force beam, of the test box, and the front-end counter-force beam and the rear-end counter-force beam are connected through a pull rod; loading oil cylinders perpendicular to the test box are arranged at each end of the inner side of the frame and on the back-end counter-force beam, and a loading plate is arranged in the test box; a pipe body is also arranged in the test box; according to the device, the soil pressure borne by the supporting structure in the tunnel excavation process can be simulated, and the influence of water pressure and ground temperature can be simulated through the arrangement of the pipe body and the water pipe.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel excavation experimental simulation, and in particular relates to a tunnel excavation support three-dimensional loading test system. Background Art

[0002] my country has built the world's largest number of tunnels with the longest total mileage using the drilling and blasting method. Researching the drilling and blasting excavation method and technology is of great significance to the formation of a tunnel construction technology system suitable for my country's national conditions. Since my country began to implement the drilling and blasting method in the early 19th century, the drilling and blasting method has always played an important role in tunnel excavation methods. Even in the 21st century, when various new excavation methods emerge in an endless stream, the drilling and blasting method is still widely used. With the continuous development of my country's tunnel transportation engineering, the construction of highway and railway tunnels continues to advance to remote mountainous areas. The environmental problems faced by the construction will become more and more complex, facing complex geological conditions such as karst, rich water, high water pressure, high ground stress, and high ground temperature. Therefore, the difficulty and requirements for tunnel drilling and blasting excavation have also been raised to a higher level.

[0003] In view of the complex environment faced by tunnel drilling and blasting excavation, it is particularly important to carry out research on tunnel excavation support by drilling and blasting. Through three-dimensional experimental simulation of tunnel drilling and blasting excavation support, the role form and mechanism of each support structure in the excavation process are explored, and the relationship between the interaction between each structure is clarified, which plays a certain guiding role in the actual tunnel excavation process. Simulation tests of tunnel excavation support by drilling and blasting have been widely carried out at home and abroad. However, these simulation tests are often carried out by simulating different stress conditions of the stratum, and some may be carried out by simulating the combined effect of stratum stress and groundwater environment, while excavation simulations for more complex conditions are less. In view of the above problems, it is necessary to study and design a set of test devices that can simulate from simple to complex environments. Only simple operations are needed to realize the simulation of tunnel excavation support under the influence of multiple factors, thereby providing reliable theoretical guidance for tunnel excavation support under complex environments. Summary of the invention

[0004] In view of this, the present invention provides a three-dimensional loading test system for tunnel excavation support to solve the problem in the prior art that simulation tests are often carried out by simulating different stress conditions of the strata, and some may be carried out by simulating the combined effects of stratum stress and groundwater environment, while there are few excavation simulations under more complex conditions.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A three-dimensional loading test system for tunnel excavation support comprises a frame, an extension cushion beam is provided at the bottom of the frame, a test box and a rear end reaction beam are slidably connected to the extension cushion beam, a front end reaction beam is provided on the side of the test box away from the rear end reaction beam, and the front end reaction beam and the rear end reaction beam are connected by a pull rod; a loading cylinder perpendicular to the test box is provided at each end of the inner side of the frame and the rear end reaction beam, and a loading plate cooperating with the loading cylinder in each direction is provided in the test box; a pipe body is also provided in the test box, and one end of the pipe body passes through the outside of the test box and is connected to a water supply pipe.

[0007] In this technical solution, it should be noted that the front reaction beam is integrated with the test box. The test box is mainly welded into an integral structure with steel plates, and an arc-shaped structure is formed at the junction. The test box and the box cover are separated from each other, and the installation surface is sealed with a sealing strip. The inside of the test box meets the requirements of five surfaces for push loading. The loading plate is placed in the corresponding position inside the test box by hoisting, and assembled and matched by a reasonable combination method. The wall of the test box has a certain thickness and can withstand a certain water pressure. The frame mainly bears the reaction force during loading and consists of two parts. One part is the upper and lower left and right reaction frame device, that is, the U-shaped combined frame. One part is the rear loading surface reaction device, that is, the loading reaction frame on the front and rear. The U-shaped combined frame is composed of four single beams. And a reinforcing rib is added on the inner side of the corner point of the U-shaped combined frame. The front and rear reaction frames are composed of the rear reaction beam and the front reaction beam through a tie rod. Threads are machined at both ends of the tie rod, and the tie rod and the rear reaction beam are fixed together with nuts to provide a support platform for cylinder loading. In addition, in this solution, the upper water pipe can be connected to an external heat source or water source to simulate different water pressures or temperatures. In summary, in the present invention, pressure can be applied to the loading plate by the loading cylinders in the up, down, left and right directions, and a reaction structure can be formed between the test box and the rear end reaction beam in the horizontal direction. The loading cylinder on the rear end reaction beam applies a lateral force to the loading plate, which can accurately simulate the soil pressure on the support structure during tunnel excavation. The setting of the pipe body and the water pipe can simulate the influence of water pressure and ground temperature, which solves the problem that the current test device and method cannot fully test the durability of the tunnel support structure under the action of complex environments. The device has many advantages such as diverse functions, convenient operation, and efficient system.

[0008] Preferably, the outer side of the test box is provided with a water tank and a cold and hot source air box which can be connected to the water supply pipe respectively.

[0009] In this technical solution, it should be noted that when the upper water pipe is connected to the water tank, the water pressure is mainly controlled by the high-pressure water pump; when the upper water pipe is connected to the cold and hot source air box, it is connected to the cold and hot source air box and the centrifugal fan through the air duct, and the cold and hot air in the cold and hot source air box is transported to the inside of the multi-functional test box through the centrifugal fan to achieve temperature control of the test soil.

[0010] Preferably, the tube body is distributed in a curve, and a plurality of through holes are opened on its side wall.

[0011] In this technical solution, it should be noted that the pipe body is installed on the front reaction beam and has two rows. By opening a number of through holes on its surface, the surface area and penetration efficiency of the pipe are increased, thereby accelerating the application of water pressure and temperature to the test soil.

[0012] Preferably, a water pipe is provided at the bottom of the test box, and a valve is provided at the water pipe.

[0013] In this technical solution, it should be noted that the sewer pipe is used for drainage, and the valve is used to realize the opening and closing control of the sewer pipe.

[0014] Preferably, one end of the test box facing each loading plate is slidably connected with a force transmission column, and the force transmission column is opposite to the corresponding loading cylinder.

[0015] In this technical solution, it should be noted that holes are provided on the test box, and the force transfer column can be inserted into the holes to achieve loading of the loading plate. In addition, the gap between the force transfer column and the hole is sealed to ensure the sealing of the multifunctional test box during the loading process.

[0016] Preferably, each loading plate is provided with an anti-tipping screw, the anti-tipping screw is perpendicular to the loading plate and one end of the anti-tipping screw is fixed to the test box, and the loading plate is slidably sleeved on the anti-tipping screw.

[0017] In this technical solution, it should be noted that each loading plate has four anti-tipping screws, and the anti-tipping screws are used to control the sliding of the loading plate to prevent it from deflecting during the loading process, so that it can apply pressure evenly throughout the entire loading process.

[0018] Preferably, a corner formed between two adjacent loading plates is provided with a corner plate, and the loading plate and the corner plate can slide relative to each other.

[0019] In this technical solution, it should be noted that the angle plates are mainly used to ensure that each loading plate 5 does not affect each other during the sliding process of applying pressure, thereby achieving single-sided or multi-sided loading of the test soil.

[0020] Preferably, a guide rail is provided on the top of the extension cushion beam, and the rear reaction beam and the test box are slidably connected to the guide rail through rollers. Limit blocks are respectively provided at both ends of the guide rail to prevent the test box from falling off.

[0021] Preferably, a hole is provided through one side of the test box, and the hole is provided to simulate the hole of tunnel excavation.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. In the present invention, pressure can be applied to the loading plate by the loading cylinders in the up, down, left and right directions, and a reaction force structure can be formed between the test box and the rear reaction beam in the horizontal direction. The loading cylinder on the rear reaction beam can apply a lateral force to the loading plate, which can accurately simulate the soil pressure on the support structure during tunnel excavation. The setting of the pipe body and the water pipe can simulate the influence of water pressure and ground temperature, which solves the problem that the current test device and method cannot fully test the durability of the tunnel support structure under the action of complex environment. The device has many advantages such as diverse functions, convenient operation, and efficient system;

[0024] 2. In the present invention, by combining and gradient controlling soil pressure, water pressure, temperature load, etc., the influence of various environmental factors on the tunnel support structure in a complex environment can be simulated, forming a systematic study of the tunnel support structure in a complex environment, which has the characteristics of integrated multi-purpose and efficient system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of the overall structure of a three-dimensional loading test system for tunnel excavation support provided by the present invention;

[0027] Figure 2 A schematic diagram of a frame and an extended cushion beam of a three-dimensional loading test system for tunnel excavation support provided by the present invention;

[0028] Figure 3 A schematic diagram of a test box for a three-dimensional loading test system for tunnel excavation support provided by the present invention;

[0029] Figure 4 A schematic diagram of a loading plate in a multifunctional test box of a tunnel excavation support three-dimensional loading test system provided by the present invention;

[0030] Figure 5 A cross-sectional view of a test box of a tunnel excavation support three-dimensional loading test system provided by the present invention;

[0031] Figure 6 A schematic diagram of a test box for a three-dimensional loading test system for tunnel excavation support provided by the present invention;

[0032] Figure 7 The overall structural cross-section diagram of a tunnel excavation support three-dimensional loading test system provided by the present invention;

[0033] Among them: 1-test box; 2-box cover; 3-front reaction beam; 4-force transmission column; 5-loading plate; 6-anti-overturning screw; 7-angle plate; 8-pull rod; 9-nut; 10-rear reaction beam; 11-frame; 12-loading cylinder; 13-guide rail; 14-roller; 15-extension cushion beam; 16-limit block; 17-upper water pipe; 18-lower water pipe; 19-tube body; 20-positioning slider. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0040] Example

[0041] like Figure 1-Figure 7 As shown, a three-dimensional loading test system for tunnel excavation support is disclosed in an embodiment of the present invention. The multifunctional test box 1 is composed of a box body and a box cover 2. The front reaction beam 3 is welded and fixed to the box body. The rear reaction beam 10 is combined with the multifunctional test box 1 through a pull rod 8, and is fixed with nuts 9 on both sides of the pull rod 8, thereby forming a front and rear loading reaction device; the front and rear loading reaction devices are placed on the guide rail 13 of the translation system in the form of rollers 14, and limited blocks 16 are installed on both sides of the guide rail 13 to prevent the multifunctional test box 1 from moving out of the guide rail 13 and falling; outside the four sides of the multifunctional test box, there is a U-shaped combined frame 11 structure, which is welded with the guide rail extension cushion beam 15 of the translation system, and together constitutes a stable support system of the test system. A loading cylinder 12 for loading is installed on the U-shaped combined frame 11 and the rear reaction beam 10. The loading cylinder 12 is connected to the hydraulic control system through an oil pipe, and the five surfaces of the test soil body are loaded and controlled by the hydraulic control system.

[0042] like Figure 2 As shown, in this embodiment: the translation system is composed of a guide rail 13, a guide rail extension pad beam 15 and a limit block 16. The guide rail 13 is placed above the guide rail extension pad beam 15. The limit blocks 16 are installed at both ends of the guide rail 13 to limit the sliding range of the roller 14 under the multifunctional test box 1 and the rear end reaction beam 10 to prevent them from falling from both ends; the frame 11 is welded by multiple steel beams and is welded and combined with the guide rail extension pad beam 15 at the bottom to form a stable combined structure, providing a stable support system for the test; The track 13 is also equipped with a positioning slider 20 for fixing the position of the multifunctional test box 1 and the rear end reaction beam 10. When fixing, the two rear positioning sliders 20 can be slid to the corresponding marking scales first, and the nuts on the positioning sliders 20 can be tightened to fix them. Then, the multifunctional test box 1 and the rear end reaction beam 10 can be pushed to the two fixed positioning sliders 20, and finally, the remaining two positioning sliders 20 can be slid to the rollers 14 at the bottom of the multifunctional test box 1, and the nuts can be tightened to fix them. This can fix the position of the multifunctional test box 1 and the rear end reaction beam 10.

[0043] like Figure 3As shown, in this embodiment: the test box 1 is composed of a box body, a box cover 2 and a front end reaction beam 3, the front end reaction beam 3 and the box body are combined together by welding, and a hole is opened in the middle of the front end reaction beam 3 for simulating the excavation of a soil cavern; a plurality of holes are also opened on the surface of the box body and the box cover 2, and these holes are used to place force transfer columns 44 so as to transfer the pressure of the cylinder 12 to the loading plate 5. Since the position of the multifunctional test box 1 and the rear end reaction beam 10 is fixed, the force transfer column 44 can be ensured to fit accurately with the loading cylinder 12 during loading, thereby ensuring the force transmission stability and safety of the force transfer column 44, and realizing the simulation of soil pressure on multiple surfaces of the test soil.

[0044] like Figure 4 As shown, in this embodiment: the loading plate 5 is a key component for realizing the oil cylinder simulating soil pressure loading. The loading plate 5 evenly applies the pressure transmitted from the force transmission column 44 to the soil surface in contact with the loading plate 5, and controls the sliding of the loading plate 5 through the anti-overturning screw 6 to prevent it from deflecting during the loading process, so that it can apply pressure evenly during the entire loading process.

[0045] like Figure 5 As shown; the figure clearly shows the relationship between the loading plate 5, the multifunctional test box and the rear end reaction beam 10. The loading plate 5 is located inside the multifunctional test box. The loading plate 5 transmits the oil pressure to the soil surface evenly through the force transmission column 44 in the direction constrained by the anti-overturning screw 6, thereby realizing the simulation of soil pressure; the rear end reaction beam 10 is connected by the pull rod 8 and fixed by the nut 9, and is combined with the multifunctional test box to form a front and rear loading reaction device; the loading of the test soil in the front and rear directions is realized by the oil cylinder 12 installed on the rear end reaction beam 10.

[0046] like Figure 6 As shown; the rear reaction beam 10 is connected by a pull rod 8 and fixed by a nut 9, and is combined with the multifunctional test box to form a front and rear loading reaction device; a water pipe is installed on the upper surface and the bottom surface of the multifunctional test box, which are a water inlet pipe 17 and a water outlet pipe 18 respectively; by connecting a high-pressure water pipe at the water inlet pipe 17, and then connecting a high-pressure water pump through the high-pressure water pipe, after closing the water outlet pipe 18, water pressure is applied to the inside of the multifunctional test box through the high-pressure water pump, and the transported high-pressure water penetrates into the test soil through the water penetration pipe 19 to achieve the simulation of the high water pressure of the test soil; by installing air ducts at the water inlet pipe 17 and the water outlet pipe 18, and then connecting the air ducts to the centrifugal fan and the cold and hot source air box in turn, the cold and hot air in the cold and hot source air box is transported to the inside of the multifunctional test box through the centrifugal fan, and then penetrates into the soil through the temperature exchange pipe, thereby achieving the temperature control of the test soil.

[0047] like Figure 7The figure shown can clearly show the internal situation of the test system in the overall assembly state. Other structures have been explained clearly in the above figure and will not be repeated here. The water permeation tube 19 or temperature exchange tube 19 is mainly introduced here. Figure 6 The content mentioned above states that if the water inlet pipe 17 is connected to a high-pressure water pump, water pressure can be applied to the test soil. If the water inlet pipe 17 and the water outlet pipe 18 are connected to a cold and hot source air box, the temperature of the test soil can be controlled. In order to achieve water pressure application and temperature control inside the test soil, two rows of curved pipes are arranged on the inner surface of the front reaction beam 3, which are respectively located at the upper and lower parts of the inner surface of the front reaction beam 3. The two rows of curved pipes are arranged in a curved manner and buried inside the soil. The surface is covered with small holes, thereby increasing the surface area and penetration efficiency of the pipes and accelerating the application of water pressure and temperature to the test soil.

[0048] like Figure 2 As shown, in another embodiment, the force transmission column 4 and the loading cylinder 12 need to be accurately connected to ensure safe and reliable loading, and the positions of the rear end reaction beam 10 and the test box 1 are fixed by four positioning sliders 20 installed at both ends of the track 13 to ensure that the force transmission column 4 is aligned with the loading cylinder 12; scales are marked on the track 13, and the positioning slider 20 can be accurately positioned by relying on the scales, and the positioning slider 20 is fixed by tightening the nut on the positioning slider 20, so as to fix the rear end reaction beam 10 and the test box 1.

[0049] The circuits, electronic components and modules involved are all prior art and can be fully implemented by those skilled in the art. Needless to say, the content protected by the present invention does not involve improvements to software and methods.

[0050] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0051] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional loading test system for tunnel excavation support, characterized in that: The invention comprises a frame (11), wherein an extension cushion beam (15) is provided at the bottom of the frame (11), a test box (1) and a rear end reaction beam (10) are slidably connected to the extension cushion beam (15), a front end reaction beam (3) is provided on a side of the test box (1) away from the rear end reaction beam (10), and the front end reaction beam (3) and the rear end reaction beam (10) are connected via a pull rod (8); Each end of the inner side of the frame (11) and the rear end reaction beam (10) are provided with a loading cylinder (12) perpendicular to the test box (1), and a loading plate (5) cooperating with the loading cylinder (12) in each direction is provided in the test box (1); A pipe body (19) is also provided in the test box (1), and one end of the pipe body (19) extends out of the test box (1) and is connected to the water supply pipe (17).

2. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: The outside of the test box (1) is provided with a water tank and a cold and hot source air box which can be connected to the upper water pipe (17) respectively.

3. A three-dimensional loading test system for tunnel excavation support according to claim 2, characterized in that: The tube body (19) is distributed in a curved shape, and a plurality of through holes are opened on its side wall.

4. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: A water down pipe (18) is provided at the bottom of the test box (1), and a valve is provided at the water down pipe (18).

5. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: One end of the test box (1) facing each loading plate (5) is slidably connected to a force transmission column (4), and the force transmission column (4) is arranged relative to the corresponding loading cylinder (12).

6. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: Each loading plate (5) is provided with an anti-tipping screw (6), the anti-tipping screw (6) is perpendicular to the loading plate (5) and one end of the anti-tipping screw (6) is fixed to the test box (1), and the loading plate (5) is slidably mounted on the anti-tipping screw (6).

7. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: A corner plate (7) is provided at each corner formed between two adjacent loading plates (5), and the loading plates (5) and the corner plates (7) can slide relative to each other.

8. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: A guide rail (13) is provided on the top of the extension cushion beam (15), and the rear end reaction beam (10) and the test box (1) are both slidably connected to the guide rail (13) via rollers (14).

9. A three-dimensional loading test system for tunnel excavation support according to claim 8, characterized in that: Limit blocks (16) are respectively provided at both ends of the guide rail (13), and four positioning slide blocks are also provided at both ends of the roller (14) on the rail (13) for fixing the positions of the rear reaction beam (10) and the test box (1).

10. A three-dimensional loading test system for tunnel excavation support according to claim 1, characterized in that: A hole is provided through one side of the test box (1).

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