True three-dimensional stress loading system for vibration table test and use method

Abstract

The invention provides a true three-dimensional stress loading system for a vibration table test and a use method, the true three-dimensional stress loading system comprises a loading device, a control device and an air compressor, and the loading device comprises a top plate, a counter-force cylinder, a bottom plate and five compression parts; each of the five compression parts comprises a plurality of telescopic rods, a plurality of loading airbags and a loading plate, and a square loading airbag loading mode is adopted, so that the mass of the true three-dimensional stress loading system can be reduced to the greatest extent while test loading of the vibration table is realized; a stiffened plate is arranged on the inner wall of the counter-force cylinder, and the stiffened plate and the top plate provide counter-force for the loading air bag; the control system and the air pressure control system are used for loading the test model and acquiring data in the test process of the vibration table; the square loading air bag provides flexible loading for the test model in the direction of the telescopic rod through inflation, the simulation problem of different surrounding rock three-dimensional stress fields is solved, and convenience is provided for researching dynamic response of high-stress underground cavern surrounding rock in a high-seismic-intensity area.

Description

Technical Field

[0001] The present invention belongs to the technical field of geotechnical engineering, and in particular relates to a true three-dimensional constant pressure servo ground stress loading test system for a shaking table test and a use method thereof. Background Art

[0002] For deep underground projects under construction and planned in high-intensity seismic zones in western my country, particularly deep, high-stress large underground caverns (clusters), the risks of high-side wall failure and large unloading deformation under complex geological environments are prominent, and the surrounding rock deformation and failure behaviors are complex. As a key component of major national infrastructure projects, deep, high-stress large underground caverns (clusters) play a significant role in safeguarding national resource security and promoting socioeconomic development. They are essential infrastructure for national strategic and lifeline projects. Historical cases of underground cavern failure during earthquakes highlight the importance of conducting seismic research on high-stress underground caverns and provide fundamental data and key breakthroughs for this research. Analyzing the deformation patterns and failure mechanisms of cavern surrounding rock under true triaxial stress conditions under earthquakes will help improve the theoretical level of seismic design for major underground projects in western my country and is an important prerequisite for ensuring the safe operation and lifecycle maintenance of major national lifeline projects. Due to the lack of actual observational data, the analysis of the deformation and failure process of surrounding rock in true triaxial underground caverns in high-seismic intensity zones has primarily relied on experimental simulation and numerical analysis. Compared with numerical simulation and other means, model tests are more vivid and intuitive, and can directly reflect the engineering geological characteristics of the surrounding rock of true three-dimensional underground caverns. These characteristics make model tests indispensable and key in research.

[0003] Currently, existing loading systems for underground cavern surrounding rock mechanics model tests are mainly divided into rigid hydraulic loading systems and flexible airbag loading systems. Rigid hydraulic loading systems are generally heavy. In shaking table model tests, the load bearing capacity of the shaking table is relatively small. Due to the heavy weight of existing rigid hydraulic loading systems, the load on the shaking table increases, making them unsuitable for direct application in shaking table model tests. In addition, the natural frequency of rigid hydraulic loading systems during vibration is high, which significantly affects the test results and makes it difficult to achieve the expected test results. Existing flexible airbag loading systems have a single loading direction and do not consider true triaxial stress loading conditions, making it impossible to truly reproduce the dynamic response characteristics of rock under true triaxial stress under earthquake action.

[0004] Therefore, how to provide a true three-dimensional stress loading system for shaking table testing that can truly simulate the dynamic response characteristics of high-stress underground rock masses is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a true three-dimensional stress loading system for vibration table testing and a method of use, so as to solve at least one of the above technical problems.

[0006] To solve the above technical problems, in a first aspect, the present invention provides a true three-axis stress loading system for a shaking table test, the true three-axis stress loading system comprising:

[0007] The loading device comprises a top plate, a reaction cylinder, a bottom plate and five compression members; the bottom of the reaction cylinder is connected to the bottom plate, and the bottom plate is detachably mounted on the vibration test bench; the top of the reaction cylinder is connected to the top plate; four stiffening plates are provided inside the reaction cylinder, and the four stiffening plates, the top plate and the bottom plate together form a stress space, and the test model is located in the stress space; the five compression members are respectively arranged on the four side surfaces and the top surface of the test model; wherein the five compression members each comprise a plurality of telescopic rods, a plurality of loading airbags and a loading plate, one end of a plurality of the telescopic rods being connected to the outer side surface of the loading plate, the other end of a plurality of the telescopic rods in the compression members located on the four side surfaces of the test model being connected to the corresponding stiffening plates, and the other end of a plurality of the telescopic rods in the compression members located on the top surface of the test model being connected to the top plate; a plurality of the loading airbags are evenly arranged between the plurality of telescopic rods, and the inner side surface of the loading plate is connected to the test model;

[0008] A control device and an air compressor are provided. A stress sensor and a strain sensor are pre-embedded in the test model. The stress sensor and the strain sensor are electrically connected to the control device. Each loading airbag is connected to the air compressor via an inflation tube.

[0009] In the first aspect, optionally, the reaction cylinder is provided with a plurality of reserved holes, and the plurality of reserved holes are all connected to the stress space.

[0010] In the first aspect, optionally, the top and bottom of the reaction cylinder are provided with outward-extending mounting rings, and the two mounting rings are integrally formed with the reaction cylinder; a plurality of first bolt holes are provided on the two mounting rings, so as to be detachably connected to the top plate and the bottom plate through the plurality of first bolt holes by M24 bolts.

[0011] In the first aspect, optionally, the top of the top plate is vertically provided with crisscrossing reinforcing ribs.

[0012] In the first aspect, optionally, a return spring is provided inside the loading airbag.

[0013] In the first aspect, optionally, a plurality of second bolt holes are opened on the base plate, so that the reaction cylinder can be mounted on the base plate through the second bolt holes, and the base plate can be mounted on the vibration test bench.

[0014] In the first aspect, optionally, the number of loading airbags located on the four peripheral sides and the top surface of the test model is four, and the four loading airbags are arranged in a matrix of two rows and two columns; a plurality of telescopic rods are evenly distributed around the four loading airbags.

[0015] In a second aspect, the present invention provides a method for using the true three-dimensional stress loading system described in Example 1, the method comprising:

[0016] Cast and manufacture the test model, bury the stress sensor in the test model, and maintain the test model until it meets the test standards;

[0017] Installing the true three-axis stress loading system on a vibration test bench and placing the test model in the loading device;

[0018] Connect the inflation tube to the air compressor, and electrically connect the stress sensor and the air compressor to the control device;

[0019] Inputting loading control information into the control device, which converts the loading control information into an air pressure value and outputs it to the air compressor;

[0020] The air compressor inflates and deflates the loading airbag through the inflation tube according to the obtained air pressure value, and adjusts the pressure value in the corresponding loading water bag through the pressure reducing valve according to the test requirements. At this time, the telescopic rod expands and contracts accordingly with the volume change of the loading airbag, thereby driving the loading plate to move along the expansion and contraction direction to apply stress to the test model, simulating true triaxial stress.

[0021] Start the vibration table and input seismic waves according to the test requirements;

[0022] The stress sensor and the strain sensor obtain dynamic response characteristic data of the test model under the simulated earthquake load, and transmit the dynamic response characteristic data to the control device;

[0023] Record dynamic response characteristic data to provide data support for the mechanical behavior, failure mechanism and dynamic response analysis of true triaxial rock under earthquake action in actual engineering.

[0024] In the second aspect, the step of installing the true three-axis stress loading system on a vibration test bench and placing the test model in the loading device comprises:

[0025] Install the bottom plate to the vibration test bench, and install the bottom of the reaction cylinder to the bottom plate,

[0026] Hoisting the test model into the reaction cylinder and placing the test model at the center of the base plate;

[0027] Loading plates, several telescopic rods and loading airbags are installed on the four sides of the test model and between the four stiffening plates;

[0028] Pass the inflation tube and the stress sensor line through the reserved hole on the reaction cylinder;

[0029] A loading plate, a plurality of telescopic rods and a loading airbag are installed between the top surface of the test model and the top plate;

[0030] Apply petroleum jelly on the surface of all the loaded air bags;

[0031] Install the top plate onto the top of the reaction cylinder.

[0032] Beneficial effects:

[0033] The present invention provides a true three-dimensional stress loading system for vibration table test and its using method, comprising a loading device, a control device and an air compressor, the loading device comprising a top plate, a reaction cylinder, a bottom plate and five compression members; the bottom of the reaction cylinder is connected to the bottom plate, and the bottom plate can be detachably mounted on the vibration test table; four stiffening plates are arranged inside the reaction cylinder, and the four stiffening plates are arranged perpendicularly to the bottom plate, and the four stiffening plates are arranged symmetrically so that two opposite stiffening plates are parallel to each other and any two adjacent stiffening plates are perpendicular to each other; it is used to strengthen the overall strength of the reaction cylinder, provide reaction force for the loading airbags located on the four peripheral sides of the test model, ensure that the reaction cylinder does not deform during the loading process, and improve the accuracy of the test; the four stiffening plates, the top plate and the bottom plate are enclosed to form a stress space, the test model is located in the stress space, the top of the reaction cylinder is connected to the top plate, and provides reaction force for the loading airbags located on the top surface of the test model; the five compression members are respectively arranged on the four sides and the top surface of the test model, and are ... to provide stress to the test model; among them, the five compression parts all include several telescopic rods, several loading airbags and loading plates, and a square loading airbag is used for loading. Since the loading airbag is made of flexible material and has light weight, its own natural frequency has little effect on the test model, and the stress boundary effect generated is more in line with the actual geomechanics principle; both ends of several telescopic rods are welded and fixed to the loading plate and the corresponding stiffening plate or top plate. During the true triaxial stress simulation test, as the loading airbag is inflated and the volume expands, the telescopic rod can be extended or shortened accordingly; several telescopic rods are symmetrically and evenly arranged along the surface of the friction reduction plate, which can assist in fixing the loading airbag on the one hand and provide support for the loading plate on the other hand, so that the stress applied to the surface of the test model after the loading airbag is pressurized and expanded is uniform; stress sensors and strain sensors are pre-embedded in the test model, and the stress sensors and strain sensors are both electrically connected to the control device; each loading airbag is connected to the air compressor through an inflation tube;

[0034] Based on this, a true triaxial stress loading system for shaking table tests was constructed. By setting up multiple loading air bags, different pressures were applied to the test model to simulate the true triaxial stress state of the deep underground rock mass. In combination with the shaking table test, the mechanical behavior of deep underground rocks in high seismic intensity areas was truly reproduced, and reasonable test simulation data was obtained. The state of deep underground rocks under the influence of earthquakes and true triaxial stress was simulated, and test data was obtained to provide data support for exploring the dynamic response and failure mechanism of deep underground rocks in high seismic intensity areas and proposing effective earthquake prevention and control measures.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic structural diagram of a true three-axis stress loading system for a shaking table test provided in an embodiment of the present application;

[0038] Figure 2 A cross-sectional view of a true three-axis stress loading system for a shaking table test provided in an embodiment of the present application;

[0039] Figure 3 A schematic diagram of a partial structure of a true three-axis stress loading system for a shaking table test provided in an embodiment of the present application;

[0040] Figure 4 A test model of a true three-axis stress loading system for a vibration table test and a schematic diagram of the structure of five compression components provided in an embodiment of the present application;

[0041] Reference numerals:

[0042] 1—loading device;

[0043] 11—top plate;

[0044] 111—Reinforced ribs;

[0045] 12—reaction cylinder;

[0046] 121—stiffened plate;

[0047] 122—reserved hole;

[0048] 123—Mounting ring;

[0049] 13—base plate;

[0050] 14—compression element;

[0051] 141—telescopic rod;

[0052] 142—loading airbag;

[0053] 143—loading plate;

[0054] 2—control device;

[0055] 3—Air compressor;

[0056] 4—Test model; DETAILED DESCRIPTION

[0057] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0058] At the same time, in the embodiments of this specification, when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used in the embodiments of this specification are for illustrative purposes only and are not intended to limit the present invention.

[0059] Example 1:

[0060] See also Figure 1-3 , this embodiment 1 provides a true three-dimensional stress loading system for vibration table test, the true three-dimensional stress loading system includes: a loading device 1, the loading device 1 includes a top plate 11, a reaction cylinder 12, a bottom plate 13 and five compression members 14; the bottom of the reaction cylinder 12 is connected to the bottom plate 13, and the bottom plate 13 can be detachably mounted on the vibration test table; the top of the reaction cylinder 12 is connected to the top plate 11; four stiffening plates 121 are provided inside the reaction cylinder 12, and the four stiffening plates 121, the top plate 11 and the bottom plate 13 together form a stress space, and the test model 4 is located in the stress space; the five compression members 14 are respectively arranged on the four sides and the top surface of the test model 4; wherein, the five compression members 14 each include a plurality of telescopic rods 141, a plurality of loading airbags 142 And a loading plate 143, one end of several telescopic rods 141 is connected to the outer side of the loading plate 143, the other ends of several telescopic rods 141 in the compression parts 14 located on the four sides of the test model 4 are connected to the corresponding stiffening plates 121, and the other ends of several telescopic rods 141 in the compression parts 14 located on the top surface of the test model 4 are connected to the top plate 11; several loading airbags 142 are evenly distributed between the several telescopic rods 141, and the inner side of the loading plate 143 is connected to the test model 4; a control device 2 and an air compressor 3, stress sensors and strain sensors are pre-embedded in the test model 4, and the stress sensors and strain sensors are both electrically connected to the control device 2; each loading airbag 142 is connected to the air compressor 3 through an inflation tube.

[0061] Specifically, the present invention provides a true three-dimensional stress loading system for vibration table test, including a loading device 1, a control device 2 and an air compressor 3, the loading device 1 includes a top plate 11, a reaction cylinder 12, a bottom plate 13 and five compression members 14; the bottom of the reaction cylinder 12 is connected to the bottom plate 13, and the bottom plate 13 can be detachably mounted on the vibration test table; four stiffening plates 121 are provided inside the reaction cylinder 12, and the four stiffening plates 121 are arranged perpendicular to the bottom plate 13, and the four stiffening plates 121 are arranged symmetrically so that the two opposite stiffening plates 121 are parallel to each other and opposite to each other. Any two adjacent stiffening plates 121 are perpendicular to each other; they are used to strengthen the overall strength of the reaction cylinder 12, provide reaction force for the loading airbags 142 located on the four sides of the test model 4, ensure that the reaction cylinder 12 does not deform during the loading process, and improve the accuracy of the test; the four stiffening plates 121, the top plate 11 and the bottom plate 13 together form a stress space, and the test model 4 is located in the stress space. The top of the reaction cylinder 12 is connected to the top plate 11 to provide reaction force for the loading airbags 142 located on the top surface of the test model 4; the five compression members 14 are respectively arranged on the four sides and The top surface is used to provide stress to the test model 4; wherein, the five compression members 14 each include a plurality of telescopic rods 141, a plurality of loading airbags 142 and a loading plate 143, and a square loading airbag 142 is used for loading. Since the loading airbag 142 is made of flexible material and has a light weight, its own natural vibration frequency has little effect on the test model 4, and the stress boundary effect generated is more in line with the actual geomechanics principle; both ends of the plurality of telescopic rods 141 are welded and fixed to the loading plate 143 and the corresponding stiffening plate 121 or the top plate 11. During the true triaxial stress simulation test, As the loading airbag 142 is inflated and expands, the telescopic rod 141 can be extended or shortened accordingly; a plurality of telescopic rods 141 are symmetrically and evenly arranged along the surface of the friction reduction plate. On the one hand, they can help fix the loading airbag 142, and on the other hand, they can provide support for the loading plate 143, so that the stress applied to the surface of the test model 4 after the loading airbag 142 is pressurized and expanded is uniform; stress sensors and strain sensors are pre-embedded in the test model 4, and the stress sensors and strain sensors are both electrically connected to the control device 2; each loading airbag 142 is connected to the air compressor 3 through an inflation tube.

[0062] In some possible implementations, the reaction cylinder 12 is provided with a plurality of reserved holes 122 , and the plurality of reserved holes 122 are all connected to the stress space.

[0063] Specifically, the provision of the reserved hole 122 facilitates the wiring of the stress sensor, the strain sensor and the inflation tube.

[0064] In some possible embodiments, the top and bottom of the reaction cylinder 12 are both provided with outward-extending mounting rings 123, and the two mounting rings 123 are integrally formed with the reaction cylinder 12; a plurality of first bolt holes are provided on the two mounting rings 123, so as to be detachably connected to the top plate 11 and the bottom plate 13 through the plurality of first bolt holes by M24 bolts; the top of the top plate 11 is vertically provided with criss-crossing reinforcing ribs 111.

[0065] Specifically, if Figure 3 As shown, the top and bottom of the reaction cylinder 12 are both provided with outward-expanding mounting rings 123, and a plurality of first bolt holes are opened on the two mounting rings 123, so as to facilitate the detachable connection of the top plate 11 and the bottom plate 13 through the plurality of first bolt holes by means of M24 bolts; the top of the top plate 11 is vertically provided with criss-crossing reinforcing ribs 111, which are used to strengthen the overall strength of the top plate 11 and provide a reaction force for the loading airbag 142 located on the top of the test model 4, so as to ensure that the top plate 11 does not deform during the loading process, reduce the test error, and thus improve the accuracy of the test.

[0066] In some possible implementations, a return spring is disposed inside the loading airbag 142 .

[0067] Specifically, a return spring is provided inside each loading airbag 142. Since the loading airbag 142 needs to be repeatedly inflated and deflated to simulate different stress levels during the experiment, the return spring can assist the loading airbag 142 to reach a stable and uniform state within the inflation stroke through the pre-compressed elastic force, so that the loading airbag 142 maintains uniform contact with the corresponding stiffened plate 121 or top plate 11 after being expanded, avoiding excessive local pressure and inconsistent heights on the left and right sides.

[0068] In some possible implementations, a plurality of second bolt holes are opened on the bottom plate 13 , so that the reaction cylinder 12 can be mounted on the bottom plate 13 through the second bolt holes, and the bottom plate 13 can be mounted on the vibration test bench.

[0069] Specifically, a plurality of second bolt holes are prefabricated on the bottom plate 13 for integrally mounting the reaction cylinder 12 , the bottom plate 13 and the vibration test bench, thereby stably fixing the loading device 1 and the dynamic test bench.

[0070] In some possible implementations, there are four loading airbags 142 located on the four sides and top surface of the test model 4 , and the four loading airbags 142 are arranged in a matrix of two rows and two columns; a plurality of telescopic rods 141 are evenly distributed around the four loading airbags 142 .

[0071] Specifically, four loading airbags 142 are provided on the four peripheral sides and the top surface of the test model 4; the four loading airbags 142 located on the same side are arranged in a matrix of two rows and two columns (i.e., stacked in a 2×2 arrangement); as a feasible method, an elastic connecting belt is bonded to the outer side of the loading airbag 142, and the loading airbag 142 is fixed to the telescopic rod 141 adjacent to the loading airbag 142 through the elastic connecting belt.

[0072] Example 2:

[0073] The present invention provides a method for using a true three-dimensional stress loading system, the method comprising:

[0074] Cast and manufacture the test model, bury the stress sensor in the test model, and maintain the test model until it meets the test standards;

[0075] Install the true three-axis stress loading system on the vibration test bench and place the test model in the loading device;

[0076] Connecting the inflation tube to the air compressor, and electrically connecting the stress sensor, the strain sensor and the air compressor to the control device;

[0077] Input the loading control information into the control device, and the control device converts the loading control information into an air pressure value and outputs it to the air compressor;

[0078] The air compressor inflates and deflates the loading airbag through the inflation tube according to the obtained air pressure value, and adjusts the pressure value in the corresponding loading water bag through the pressure reducing valve according to the test requirements. At this time, the telescopic rod expands and contracts accordingly with the volume change of the loading airbag, thereby driving the loading plate to move along the expansion and contraction direction to apply stress to the test model, simulating true triaxial stress.

[0079] Start the vibration table and input seismic waves according to the test requirements;

[0080] The stress sensor and the strain sensor obtain dynamic response characteristic data of the test model under the simulated earthquake load, and transmit the dynamic response characteristic data to the control device;

[0081] Record dynamic response characteristic data to provide data support for the mechanical behavior, failure mechanism and dynamic response analysis of true triaxial rock under earthquake action in actual engineering.

[0082] Specifically, before the test, prepare similar materials and various sensors required for the test, and check whether the required instruments and equipment are normal; according to the test model size and vibration table test conditions, design a loading plan, make a test model sample mold, and pre-embed stress sensors and strain sensors in the test model, cast the test model, and maintain the test model to meet the test standards; the stress sensors and strain sensors should be tested and calibrated with a multimeter before being buried to ensure that the monitoring instrument line connection is normal. At the same time, the stress sensors and strain sensors buried in the test model should be sealed and waterproofed in advance; assemble the loading system described in Example 1 and hoist and assemble it to the vibration test table, and place the test model in the loading system; after assembly, connect the inflation tube to the air compressor, electrically connect the stress sensor, strain sensor and air compressor to the control device, and debug until the test standard is met; when the counter-loading simulation device is assembled and fixed, it needs to be controlled before conducting the formal test. The control system is debugged and inspected. Formal tests require strict loading according to the working conditions through the control system. Loading control information is input into the control system, and the control device converts the loading control information into a pressure value and outputs it to the air compressor. The air compressor then inflates and deflates the loading airbag, adjusting the volume of the loading airbag and applying stress to the test model to simulate the high stress state of deep underground rock. The air compressor is equipped with a pressure gauge to monitor the air pressure of the loading airbag. The air compressor is also equipped with multiple inflation ports to control the air pressure of each loading airbag separately, thereby driving the loading plate to move along the direction of the telescopic rod to act on the test model. The volume of the square loading airbag is adjusted by inflation and deflation, thereby applying stress to the test model to simulate the high stress state of deep underground rock. During the true triaxial stress loading process, the sensor can use stress sensors and strain sensors to obtain the dynamic response characteristic data of the test model under seismic loads, and transmit it to the control device for recording, so that researchers can conduct subsequent vibration table research based on this data.

[0083] In some possible implementations, installing a true three-axis stress loading system on a vibration test bench and placing a test model in the loading device includes:

[0084] Install the base plate to the vibration test bench and install the bottom of the reaction cylinder to the base plate.

[0085] Hoist the test model into the reaction cylinder and place it at the center of the base plate;

[0086] Loading plates, several telescopic rods and loading airbags are installed on the four sides of the test model and between the four stiffening plates;

[0087] Pass the inflation tube and the stress sensor line through the reserved hole on the reaction cylinder;

[0088] A loading plate, a plurality of telescopic rods and a loading airbag are installed between the top surface of the test model and the top plate;

[0089] Apply petroleum jelly to all surfaces of the loaded balloon;

[0090] Install the top plate onto the top of the reaction cylinder.

[0091] Specifically, the steps of installing the true three-dimensional stress loading system on the vibration test bench and placing the test model in the loading device include: installing the base plate on the vibration test bench, and installing the bottom of the reaction cylinder on the base plate, hoisting the test model into the reaction cylinder, and placing the test model at the center of the base plate; installing loading plates, several telescopic rods and loading airbags on the four sides of the test model and between the four stiffening plates; passing the lines of the inflation tube, stress sensor and strain sensor through the reserved holes opened on the reaction cylinder; installing loading plates, several telescopic rods and loading airbags between the top surface of the test model and the top plate; applying vaseline on the surface of all loading airbags to reduce the friction between adjacent loading water bags after the water volume increases; and installing the top plate to the top of the reaction cylinder.

[0092] Finally, it should be noted that the above embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. However, such modifications, changes, or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present invention. They should all be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

[0093] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A true three-axis stress loading system for vibration table testing, characterized in that: The true three-dimensional stress loading system comprises: A loading device (1), the loading device (1) comprising a top plate (11), a reaction cylinder (12), a bottom plate (13) and five compression members (14); the bottom of the reaction cylinder (12) is connected to the bottom plate (13), and the bottom plate (13) is detachably mounted on a vibration test bench; the top of the reaction cylinder (12) is connected to the top plate (11); four stiffening plates (121) are provided inside the reaction cylinder (12), and the four stiffening plates (121), the top plate (11) and the bottom plate (13) together form a stress space, and the test model (4) is located in the stress space; the five compression members (14) are respectively arranged on the four side surfaces and the top surface of the test model (4); wherein the five compression members ( 14) comprises a plurality of telescopic rods (141), a plurality of loading airbags (142) and a loading plate (143), one end of the plurality of telescopic rods (141) is connected to the outer side surface of the loading plate (143), the other ends of the plurality of telescopic rods (141) in the compression member (14) located on the four side surfaces of the test model (4) are connected to the corresponding stiffening plates (121), and the other ends of the plurality of telescopic rods (141) in the compression member (14) located on the top surface of the test model (4) are connected to the top plate (11); the plurality of loading airbags (142) are evenly distributed between the plurality of telescopic rods (141), and the inner side surface of the loading plate (143) is connected to the test model (4); A control device (2) and an air compressor (3); a stress sensor and a strain sensor are pre-buried in the test model (4); the stress sensor and the strain sensor are both electrically connected to the control device (2); and each loading airbag (142) is connected to the air compressor (3) via an inflation tube.

2. The true three-dimensional stress loading system according to claim 1, characterized in that: The reaction cylinder (12) is provided with a plurality of reserved holes (122), and the plurality of reserved holes (122) are all connected to the stress space.

3. The true three-dimensional stress loading system according to claim 2, characterized in that: The top and bottom of the reaction cylinder (12) are both provided with outwardly extending mounting rings (123), and the two mounting rings (123) are integrally formed with the reaction cylinder (12); the two mounting rings (123) are both provided with a plurality of first bolt holes, so as to be detachably connected to the top plate (11) and the bottom plate (13) through the plurality of first bolt holes by M24 bolts.

4. The true three-dimensional stress loading system according to claim 3, characterized in that: The top of the top plate (11) is vertically provided with crisscrossing reinforcing ribs (111).

5. The true three-dimensional stress loading system according to claim 4, characterized in that: A return spring is arranged inside the loading airbag (142).

6. The true three-dimensional stress loading system according to claim 6, characterized in that: A plurality of second bolt holes are provided on the bottom plate (13), so that the reaction cylinder (12) can be mounted on the bottom plate (13) through the second bolt holes, and the bottom plate (13) can be mounted on the vibration test bench.

7. The true three-dimensional stress loading system according to claim 7, characterized in that: The number of the loading airbags (142) located on the four peripheral sides and the top surface of the test model (4) is four, and the four loading airbags (142) are arranged in a matrix of two rows and two columns; a plurality of the telescopic rods (141) are evenly arranged around the four loading airbags (142).

8. A method for using the true three-dimensional stress loading system according to any one of claims 1 to 7, characterized in that: The method of use includes: Cast and manufacture the test model, bury the stress sensor in the test model, and maintain the test model until it meets the test standards; Installing the true three-axis stress loading system on a vibration test bench and placing the test model in the loading device; Connecting the inflation tube to the air compressor, and electrically connecting the stress sensor, the strain sensor and the air compressor to the control device; Inputting loading control information into the control device, which converts the loading control information into an air pressure value and outputs it to the air compressor; The air compressor inflates and deflates the loading airbag through the inflation tube according to the obtained air pressure value, and adjusts the pressure value in the corresponding loading water bag through the pressure reducing valve according to the test requirements. At this time, the telescopic rod expands and contracts accordingly with the volume change of the loading airbag, thereby driving the loading plate to move along the expansion and contraction direction to apply stress to the test model, simulating true triaxial stress. Start the vibration table and input seismic waves according to the test requirements; The stress sensor and the strain sensor obtain dynamic response characteristic data of the test model under the simulated earthquake load, and transmit the dynamic response characteristic data to the control device; Record dynamic response characteristic data to provide data support for the mechanical behavior, failure mechanism and dynamic response analysis of true triaxial rock under earthquake action in actual engineering.

9. The method for using the true three-dimensional stress loading system according to claim 8, characterized in that: The step of installing the true three-axis stress loading system on a vibration test bench and placing the test model in the loading device comprises: Install the bottom plate to the vibration test bench, and install the bottom of the reaction cylinder to the bottom plate, Hoisting the test model into the reaction cylinder and placing the test model at the center of the base plate; Loading plates, several telescopic rods and loading airbags are installed on the four sides of the test model and between the four stiffening plates; Pass the inflation tube and the stress sensor line through the reserved hole on the reaction cylinder; A loading plate, a plurality of telescopic rods and a loading airbag are installed between the top surface of the test model and the top plate; Apply petroleum jelly on the surface of all the loaded air bags; Install the top plate onto the top of the reaction cylinder.

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