A three-dimensional loading test system for tunnel excavation and support

Abstract

This invention proposes a three-dimensional loading test system for tunnel excavation support, belonging to the field of tunnel excavation experimental simulation technology. It addresses the problem that existing technologies often simulate different stress conditions in the strata, with limited simulation of more complex excavation scenarios. The system includes a frame with an extension beam at its bottom. A test chamber and a rear reaction beam are slidably connected to the extension beam. A front reaction beam is located on the side of the test chamber away from the rear reaction beam, and the front and rear reaction beams are connected by a tie rod. Each end of the frame and the rear reaction beam are equipped with a loading cylinder perpendicular to the test chamber. A loading plate is located inside the test chamber. A pipe body is also located inside the test chamber. This invention can simulate the earth pressure on the support structure during tunnel excavation, and the pipe body and water pipes can simulate the effects of water pressure and ground temperature.

Description

Technical Field

[0001] This invention belongs to the field of tunnel excavation experimental simulation technology, specifically relating to a three-dimensional loading test system for tunnel excavation and support. Background Technology

[0002] Drill-and-blast method has always held a pivotal position in tunnel excavation, and it remains widely used even in the 21st century. With the continuous development of tunnel transportation engineering in my country, highway and railway tunnel construction is increasingly extending into remote mountainous areas. The environmental challenges faced during construction are becoming increasingly complex, including complex geological conditions such as karst, abundant water, high water pressure, high ground stress, and high ground temperature. Therefore, the difficulty and requirements for tunnel drilling and blasting excavation have also increased significantly.

[0003] Given the complex environment encountered in drill-and-blast tunnel excavation, research on tunnel excavation support using this method is particularly important. Three-dimensional experimental simulations of drill-and-blast tunnel excavation support can explore the interaction forms and mechanisms between various support structures during excavation, clarifying the relationships between these structures and providing guidance for actual tunnel excavation. Simulation tests of drill-and-blast tunnel excavation support often simulate different stress conditions in the strata, sometimes simulating the combined effects of strata stress and groundwater. However, simulations of more complex excavation conditions are less common. To address these issues, it is necessary to research and design an experimental device capable of simulating environments ranging from simple to complex. This device should allow for the simulation of drill-and-blast tunnel excavation support under the combined influence of multiple factors through simple operation, thus providing reliable theoretical guidance for tunnel excavation support in complex environments. Summary of the Invention

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

[0005] The technical solution adopted in this invention is as follows:

[0006] A three-dimensional loading test system for tunnel excavation support includes a frame, an extension pad beam at the bottom of the frame, a test chamber and a rear reaction beam slidably connected to the extension pad beam, a front reaction beam on the side of the test chamber away from the rear reaction beam, and the front reaction beam and the rear reaction beam connected by a tie rod; each end of the inner side of the frame and the rear reaction beam are equipped with a loading cylinder perpendicular to the test chamber; the test chamber is equipped with a loading plate that cooperates with the loading cylinder in each direction; the test chamber is also equipped with a pipe, one end of which extends out of the test chamber and connects to a water supply pipe.

[0007] In this technical solution, it should be noted that the front reaction beam and the test chamber are integrated. The test chamber is mainly constructed of welded steel plates, with an arc-shaped structure at the junction. The test chamber and the cover are separate, and the mounting surfaces are sealed with sealing strips. The interior of the test chamber accommodates loading from five sides. The loading plates are hoisted and placed in corresponding positions inside the test chamber, assembled using a reasonable combination method. The test chamber walls have a certain thickness to withstand a certain water pressure. The frame mainly bears the reaction force during loading and consists of two parts. One part is the upper, lower, left, and right reaction frame device, i.e., a U-shaped combined frame. The other part is the rear loading surface reaction device, i.e., the front and rear loading reaction frames. The U-shaped combined frame is composed of four single beams, with reinforcing ribs added to the inner side of the corners of the U-shaped combined frame. The front and rear reaction frames are formed by combining the rear and front reaction beams with tie rods. The ends of the tie rods are threaded and fixed to the rear reaction beam with nuts, providing a support platform for the hydraulic cylinder loading. Furthermore, in this design, the water supply pipe can be connected to an external heat source or water source to simulate different water pressures or temperatures. In summary, this invention applies pressure to the loading plate via loading cylinders in the up, down, left, and right directions. Laterally, a reaction structure is formed between the test chamber and the rear reaction beam. The loading cylinders on the rear reaction beam apply lateral force to the loading plate, accurately simulating the soil pressure on the support structure during tunnel excavation. The pipe and water pipe configuration simulates the effects of water pressure and ground temperature, solving the problem that current testing devices and methods cannot comprehensively assess the durability of tunnel support structures under complex environmental conditions. The device boasts numerous advantages, including diverse functions, convenient operation, and high system efficiency.

[0008] Preferably, the outside of the test chamber is equipped with a water tank and a cold / heat source air chamber that can be connected to the water supply pipe.

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

[0010] Preferably, the tube body is curved and has several through holes on its sidewalls.

[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 several through holes on its surface, the surface area and permeability of the pipe are increased, thereby accelerating the application of water pressure and temperature to the test soil.

[0012] Preferably, the bottom of the test chamber is provided with a drain pipe, and a valve is provided at the drain pipe.

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

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

[0015] In this technical solution, it should be noted that the test chamber has holes through which the force transmission column can pass to load the loading plate. Furthermore, the gap between the force transmission column and the holes is sealed to ensure the airtightness of the multi-functional test chamber during the loading process.

[0016] Preferably, each of the loading plates is provided with an anti-tipping screw, the anti-tipping screw is perpendicular to the loading plate and one end of it is fixed to the test chamber, 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, which control the sliding of the loading plate and prevent it from deflecting during the loading process, so that pressure can be applied evenly throughout the entire loading process.

[0018] Preferably, corner plates are provided at the corners formed between two adjacent loading plates, and the loading plates and corner plates can slide relative to each other.

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

[0020] Preferably, the top of the extended pad beam is provided with a guide rail, and both the rear reaction beam and the test chamber are slidably connected to the guide rail via rollers. Limiting blocks are provided at both ends of the guide rail to prevent the test chamber from falling off.

[0021] Preferably, the test chamber has a through-hole on one side. The through-hole is designed to simulate the opening of a 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 this invention, pressure can be applied to the loading plate by loading cylinders in the up, down, left, and right directions. A reaction structure is formed between the test box and the rear reaction beam in the lateral direction. The loading cylinders on the rear reaction beam apply lateral force to the loading plate, which can accurately simulate the soil pressure on the support structure during tunnel excavation. The setting of pipes and water pipes can simulate the effects of water pressure and ground temperature. This solves the problem that current test devices and methods cannot comprehensively assess the durability of tunnel support structures under complex environmental conditions. The device has many advantages such as multiple functions, convenient operation, and high system efficiency.

[0024] 2. In this invention, by combining and gradient-controlling earth pressure, water pressure, temperature load, etc., the influence of various environmental factors on tunnel support structures under complex environments can be simulated, forming a system study of tunnel support structures under complex environments. It has the characteristics of being multi-functional and highly efficient. Attached Figure Description

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

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

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

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

[0029] Figure 4 This invention provides a schematic diagram of the loading plate inside a multifunctional test chamber of a three-dimensional loading test system for tunnel excavation and support.

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

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

[0032] Figure 7 A cross-sectional view of the overall structure of a three-dimensional loading test system for tunnel excavation and support provided by the present invention;

[0033] The components are: 1-Test chamber; 2-Chamber cover; 3-Front-end reaction beam; 4-Force transmission column; 5-Loading plate; 6-Anti-tipping screw; 7-Angle plate; 8-Tie rod; 9-Nut; 10-Rear-end reaction beam; 11-Frame; 12-Loading cylinder; 13-Guide rail; 14-Roller; 15-Extension pad beam; 16-Limit block; 17-Water inlet pipe; 18-Water outlet pipe; 19-Pipe body; 20-Positioning slider. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. Example

[0040] like Figures 1-7As shown in the figure, this embodiment of the invention discloses a three-dimensional loading test system for tunnel excavation support. The multi-functional test chamber 1 consists of a chamber body and a cover 2. A front reaction beam 3 is welded and fixed to the chamber body, and a rear reaction beam 10 is combined with the multi-functional test chamber 1 via a tie rod 8. Nuts 9 are used to fix the tie rod 8 on both sides, thus 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 via rollers 14. Limiting blocks 16 are installed on both sides of the guide rail 13 to prevent the multi-functional test chamber 1 from falling off the guide rail 13. Around the multi-functional test chamber, there is a U-shaped combined frame structure 11, which is welded to the guide rail extension pad beam 15 of the translation system, together forming a stable support system for the test system. Loading cylinders 12 are installed on both the U-shaped combined frame 11 and the rear reaction beam 10. The loading cylinders 12 are connected to a hydraulic control system via oil pipes, and the hydraulic control system controls the loading on the five surfaces of the test soil.

[0041] like Figure 2 As shown, in this embodiment: the translation system consists of a guide rail 13, a guide rail extension beam 15, and limiting blocks 16. The guide rail 13 is placed above the guide rail extension beam 15, and limiting blocks 16 are installed at both ends of the guide rail 13 to limit the sliding range of the rollers 14 under the multi-functional test chamber 1 and the rear reaction beam 10, preventing them from falling from both ends; the frame 11 is welded together from multiple steel beams and welded together with the guide rail extension beam 15 at the bottom, thus forming a stable combined structure to provide a stable support system for the test; on the rail The track 13 is also equipped with positioning sliders 20, which are used to fix the position of the multi-functional test chamber 1 and the rear reaction beam 10. When fixing, first slide the two rear positioning sliders 20 to the corresponding marked scale and tighten the nuts on the positioning sliders 20 to fix them. Then push the multi-functional test chamber 1 and the rear reaction beam 10 to the two fixed positioning sliders 20. Finally, slide the remaining two positioning sliders 20 to the rollers 14 at the bottom of the multi-functional test chamber 1 and tighten the nuts to fix them. This will fix the position of the multi-functional test chamber 1 and the rear reaction beam 10.

[0042] like Figure 3As shown, in this embodiment: the test chamber 1 consists of a chamber body, a cover 2, and a front reaction beam 3. The front reaction beam 3 is welded to the chamber body. An opening is made in the middle of the front reaction beam 3 for excavating a simulated soil cavity. Multiple holes are also made on the surface of the chamber body and the cover 2. These holes are used to place the force transmission column 44 so that the pressure of the hydraulic cylinder 12 can be transmitted to the loading plate 5. Since the positions of the multifunctional test chamber 1 and the rear reaction beam 10 are fixed, it can be ensured that the force transmission column 44 and the loading hydraulic cylinder 12 are accurately attached during loading, thereby ensuring the force transmission stability and safety of the force transmission column 44 and realizing the simulation of soil pressure on multiple surfaces of the test soil.

[0043] like Figure 4 As shown, in this embodiment: the loading plate 5 is a key component for realizing the simulated earth pressure loading of the hydraulic cylinder. The loading plate 5 applies the pressure transmitted from the force transmission column 44 evenly to the soil surface in contact with the loading plate 5, and controls the sliding of the loading plate 5 by the anti-tipping screw 6 to prevent it from deflecting during the loading process, so that it can apply pressure evenly throughout the entire loading process.

[0044] like Figure 5 As shown in the figure, the relationship between the loading plate 5, the multi-functional test chamber, and the rear reaction beam 10 is clearly illustrated. The loading plate 5 is located inside the multi-functional test chamber. In the direction constrained by the anti-tipping screw 6, the loading plate 5 transmits oil pressure evenly to the soil surface through the force transmission column 44, thereby simulating soil pressure. The rear reaction beam 10 is connected by the tie rod 8 and fixed by the nut 9, and is combined with the multi-functional test chamber to form a front and rear loading reaction device. The loading of the test soil in the front and rear directions is achieved by the oil cylinder 12 placed on the rear reaction beam 10.

[0045] like Figure 6 As shown; the rear reaction beam 10 is connected by tie rod 8 and fixed by nut 9, and combined with the multi-functional test chamber to form a front and rear loading reaction device; a water pipe is installed on the upper surface and bottom surface of the multi-functional test chamber, namely water inlet pipe 17 and water outlet pipe 18; by connecting a high-pressure water pipe to the water inlet pipe 17, and then connecting a high-pressure water pump to the high-pressure water pipe, after closing the water outlet pipe 18, water pressure is applied to the inside of the multi-functional test chamber by the high-pressure water pump, and the high-pressure water is infiltrated into the test soil through the water infiltration pipe 19 to simulate the high water pressure of the test soil; by installing air ducts at the water inlet pipe 17 and water outlet pipe 18, and then connecting the air ducts to a centrifugal fan and a cold and hot source air box in sequence, the centrifugal fan delivers the cold and hot air in the cold and hot source air box to the inside of the multi-functional test chamber, and then infiltrates into the soil through the temperature exchange pipe, thereby realizing the temperature control of the test soil.

[0046] like Figure 7The diagram clearly shows the internal structure of the test system in its overall assembled state. Other structural elements have already been explained in the diagram above and will not be repeated here. This section focuses on the water permeation pipe 19, also known as the temperature exchange pipe 19. Figure 6 The description states that if the inlet pipe 17 is connected to a high-pressure water pump, water pressure can be applied to the test soil. If the inlet pipe 17 and outlet pipe 18 are connected to a cold / heat source air chamber, the temperature of the test soil can be controlled. To achieve water pressure application and temperature control inside the test soil, two rows of curved pipes are set on the inner surface of the front reaction beam 3, located at the upper and lower parts of the inner surface of the front reaction beam 3, respectively. 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 permeability of the pipes and accelerating the application of water pressure and temperature to the test soil.

[0047] 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. The positions of the rear reaction beam 10 and the test chamber 1 are fixed by four positioning sliders 20 installed at both ends of the track 13 to ensure that the force transmission column 4 and the loading cylinder 12 are aligned. The track 13 is marked with a scale, and the positioning sliders 20 can be accurately positioned by relying on the scale. The positioning sliders 20 are fixed by tightening the nuts on the positioning sliders 20, thereby fixing the rear reaction beam 10 and the test chamber 1.

[0048] The circuits, electronic components, and modules involved are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The scope of protection of this invention does not involve any improvement to the software and methods.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional loading test system for tunnel excavation and support, characterized in that, Includes a frame (11), the bottom of which is provided with an extension pad beam (15), on which a test chamber (1) and a rear reaction beam (10) are slidably connected, and a front reaction beam (3) is provided on the side of the test chamber (1) away from the rear reaction beam (10), and the front reaction beam (3) and the rear reaction beam (10) are connected by a tie rod (8); Each end of the inner side of the frame (11) and the rear reaction beam (10) are provided with a loading cylinder (12) perpendicular to the test chamber (1). The test chamber (1) is provided with a loading plate (5) that cooperates with the loading cylinder (12) in each direction. The test chamber (1) is also equipped with a pipe (19), one end of which extends out of the test chamber (1) and connects to the water supply pipe (17); The outside of the test chamber (1) is equipped with a water tank and a cold / heat source air tank that can be connected to the water supply pipe (17); The pipe (19) is curved and buried in the soil, with several through holes on its sidewall.

2. The three-dimensional loading test system for tunnel excavation and support according to claim 1, characterized in that, The bottom of the test chamber (1) is provided with a drain pipe (18), and a valve is provided at the drain pipe (18).

3. The three-dimensional loading test system for tunnel excavation and support according to claim 1, characterized in that, The test chamber (1) is slidably connected to a force transmission column (4) at one end facing each loading plate (5), and the force transmission column (4) is set relative to the corresponding loading cylinder (12).

4. The three-dimensional loading test system for tunnel excavation and 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 it is fixed on the test chamber (1), and the loading plate (5) is slidably sleeved on the anti-tipping screw (6).

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

6. The three-dimensional loading test system for tunnel excavation and support according to claim 1, characterized in that, The top of the extension pad beam (15) is provided with a guide rail (13), and the rear reaction beam (10) and the test box (1) are slidably connected to the guide rail (13) by rollers (14).

7. A three-dimensional loading test system for tunnel excavation and support according to claim 6, characterized in that, Limiting blocks (16) are provided at both ends of the guide rail (13). Four positioning sliders are also provided at both ends of the roller (14) on the guide rail (13) to fix the position of the rear reaction beam (10) and the test box (1).

8. The three-dimensional loading test system for tunnel excavation and support according to claim 1, characterized in that, The test chamber (1) has a through hole on one side.

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