Rock mechanics dynamic three-way shearing device

Abstract

The invention provides a rock mechanics dynamic three-way shearing device, and relates to the technical field of engineering geology and rock mechanics tests, the rock mechanics dynamic three-way shearing device comprises a device main body, the device main body comprises a first guide rail, a first test base is arranged on the first guide rail, and a second test base is arranged on the first test base; and the first test base is used for placing a test sample. According to the rock mechanics dynamic three-way shearing device provided by the invention, a test sample can be placed on the first test base, the first test base moves to the position below the normal pressure applying assembly through the first guide rail, and the normal pressure applying assembly applies pressure to the upper end face of the test sample; the second side pressure applying assembly and the third side pressure applying assembly are matched to clamp the upper half part of a test sample, the first side pressure applying assembly applies pressure to the first test base, and the first test base applies pressure to the lower half part of the test sample; in other words, cyclic loading in the first direction, cyclic loading in the second direction and normal cyclic loading can be independently achieved, and then dynamic three-way shearing is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering geology and rock mechanics test, and particularly relates to a rock mechanics dynamic three-way shearing device. BACKGROUND

[0002] The western mountainous area in China has a significant terrain elevation difference, dense active faults, active geological structure and broken rock mass structure, and under the coupling of internal and external forces, the slope stability is poor, which provides a geological basis for the incubation of collapse and landslide geological disasters; meanwhile, the region is distributed with Longmenshan, Xianshuihe, Litang-Yajiang and other seismic source areas, and has entered a seismic activity clustering period since the 21st century, which provides a dynamic basis for the incubation of geological disasters, resulting in a very high seismic landslide risk in the region.

[0003] With the implementation of the national strategies such as the Sichuan-Tibet railway and cascade hydropower development, a large number of projects will be built in the western mountainous area, which will face more severe requirements for the prevention and mitigation of seismic geological disasters, and higher requirements are put forward for the seismic design of slopes. How to accurately obtain the mechanical parameters of rock mass and structural plane under the action of earthquakes is the basis for the prevention and mitigation of seismic geological disasters and the seismic design of slopes, and has important scientific value and practical significance.

[0004] Numerous scholars have developed instruments to reveal the dynamic characteristics of soil and rock masses and obtain their dynamic mechanical parameters. For example, Jiang et al. (2004) successfully developed a servo-controlled direct shear device under constant normal stiffness conditions, suitable for loading rectangular specimens with a maximum length of 500 mm, with a maximum normal force of 200 kN and a maximum shear force of 400 kN. Konietzky et al. (2012) developed and successfully tested a large-scale dynamic rock mechanical direct shear box device, capable of loading rectangular specimens with a maximum surface area of ​​400 mm * 200 mm, with a maximum normal force of 1000 kN and a maximum shear force of 800 kN. A 40 Hz dynamic load of 500 kN can be superimposed in two directions, with a maximum shear displacement of 50 mm. Liu Bo et al. (2013) used a shearing instrument to conduct a single-cycle shear test on jointed specimens under stable normal stress, achieving a maximum shear force of 250 kN, a maximum cyclic shear stroke of 20 mm, and a maximum normal force of 100 kN. Zheng Bowen (2017) developed a novel dynamic bidirectional shear performance testing platform for rock mass structures, capable of two servo loading modes: constant normal pressure shear and constant normal stiffness shear. The maximum surface size of the shear box is 1000mm*250mm, the maximum normal load is 500KN, the maximum tangential load is 1000KN, and the maximum shear displacement is 200mm. Xie et al. (2021) developed a true triaxial electromagnetic Hopkinson bar (TEHB) system, which provides a cutting-edge testing platform for studying the three-dimensional (3D) dynamic behavior of rocks under coupled triaxial dynamic impact, and can load cubic specimens with a side length of 51mm. Cui et al. (2021) developed a novel direct shear apparatus with a specially designed shear box and loading jack structure. The stability of the shear box was significantly improved in cyclic shearing. The maximum surface size of the rectangular specimen was 150mm*150mm, the maximum normal force was 600KN, the maximum shear force was 900KN, and the maximum shear displacement was 125mm. Dang et al. (2022) emphasized the independence of servo control in two directions and developed a direct shear apparatus with force and displacement servo control in both vertical and horizontal directions. The maximum size of the shear chamber was 200mm*200mm*400mm, the maximum normal force and shear force were both 500KN, and the maximum shear displacement was 40mm. Han et al. (2024) designed and built a novel shear testing device, which includes a sealed pressure chamber and a biaxial compression frame. It can accommodate rock samples with dimensions of 152.4mm*127mm*50.8mm, and the shear chamber can withstand a maximum pressure of 10MPa. Yuan et al. (2024) emphasized the shear slip process of rock joints under different initial stress states and developed a bidirectional shear device that can conduct shear tests under dynamic disturbance and different initial shear stress conditions. The maximum size of the shear chamber was 300mm*300mm*50mm, the maximum normal force and shear force were both 150KN, and the maximum shear displacement was 30mm.

[0005] In summary, the previous rock dynamic shear test equipment is mainly for small sample unidirectional or bidirectional dynamic shear, but the ground motion during the earthquake is a complex multi-directional motion, and the soil is mainly subjected to three-directional seismic load, and there is no test equipment that can realize cyclic reciprocating loading under seismic strain rate and dynamic three-directional shear condition. SUMMARY

[0006] The rock mechanics dynamic three-directional shear device aims to solve the technical problem that the existing equipment can only perform unidirectional or bidirectional dynamic shear, but the ground motion during the earthquake is a complex multi-directional motion, and the soil is mainly subjected to three-directional seismic load, and the existing equipment cannot perform dynamic shear test.

[0007] The rock mechanics dynamic three-directional shear device comprises a device main body, wherein the device main body comprises a first guide rail, a first test base is arranged on the first guide rail, and the first test base is used for placing a test sample. A normal pressure assembly is arranged on the device main body and abuts against an upper end surface of the test sample. A first side pressure assembly is arranged at one end of a first direction of the device main body, and the first side pressure assembly is connected with the first test base. A second side pressure assembly is arranged at one end of a second direction of the device main body, and the second side pressure assembly abuts against an upper half of one side of the test sample. A third side pressure assembly is arranged at the other end of the second direction of the device main body, and the third side pressure assembly abuts against an upper half of the other side of the test sample. The first direction is perpendicular to the second direction.

[0008] In an optional embodiment, the normal pressure assembly comprises, from top to bottom, a normal pressure static oil cylinder, a normal pressure dynamic oil cylinder, a normal load sensor and a normal force transmission device; the normal force transmission device abuts against the upper end surface of the test sample. A normal shear friction bearing is arranged between the normal load sensor and the normal force transmission device. A plurality of normal displacement sensors are arranged on the normal shear friction bearing, and the normal displacement sensors are used for vertical deformation measurement of the test sample.

[0009] In an optional embodiment, one end of the first side pressure assembly is connected with an upper fixed frame, the upper fixed frame is provided with oppositely arranged force transmission members, and one end of the force transmission member abuts against the upper half of the test sample. The second side pressure assembly and the third side pressure assembly abut against one of the force transmission members. The second side pressing assembly comprises a second static oil cylinder, a second dynamic oil cylinder, a second load sensor, a second shear friction bearing and a second force transmission device arranged in sequence, and the second force transmission device abuts against a corresponding force transmission piece; A plurality of second displacement sensors are arranged on the force transmission piece, and the second displacement sensors are used to measure the deformation of the test sample in a second direction.

[0010] In an optional embodiment, the third side pressing assembly comprises a third dynamic oil cylinder, a third load sensor, a third shear friction bearing and a third force transmission device arranged in sequence, and the third force transmission device abuts against a corresponding force transmission piece.

[0011] In an optional embodiment, the first side pressing assembly comprises a first static oil cylinder, a first dynamic oil cylinder, a first load sensor and a first force transmission device arranged in sequence, and the first force transmission device is connected to the first test base; The first force transmission device is provided with a first displacement sensor, and the first displacement sensor is used to measure the deformation of the test sample in a first direction.

[0012] In an optional embodiment, the upper fixed frame comprises a first side blocking plate, a second side blocking plate, a third side blocking plate and a fourth side blocking plate; the first side blocking plate and the third side blocking plate are arranged oppositely, and both the first side blocking plate and the third side blocking plate are provided with a force transmission piece; The second side blocking plate and the fourth side blocking plate are arranged oppositely, and a fourth shear friction bearing is arranged on the inner side wall of each of the second side blocking plate and the fourth side blocking plate; the fourth shear friction bearing abuts against the upper half of the test sample; A lower notch is arranged on the second side blocking plate, and the second force transmission device is connected to the first test base through the lower notch; The first test base has four limiting stop plates, and the four limiting stop plates are arranged in a rectangular shape on the first test base; A fine adjustment block is arranged on the first test base, and the fine adjustment block is used to fix the test sample on the first test base.

[0013] In an optional embodiment, a shear box is arranged on the first test base, and the shear box comprises an upper box body and a lower box body; the upper box body abuts against the force transmission piece, and the lower box body is fixedly arranged on the first test base; An upper assembly hole is arranged in the upper box body, and a lower assembly hole corresponding to the upper assembly hole is arranged on the lower box body; An upper assembly sleeve assembly is arranged in the upper assembly hole, and a lower assembly sleeve assembly is arranged in the lower assembly hole, and the upper assembly sleeve assembly and the lower assembly sleeve assembly form a test cavity for placing a test sample. In an optional embodiment, the upper assembly sleeve assembly comprises a plurality of upper assembly sleeves arranged in sequence, the lower assembly sleeve assembly comprises a plurality of lower assembly sleeves arranged in sequence, and each upper assembly sleeve can form a test cavity with a lower assembly sleeve.

[0014] In an optional embodiment, a plurality of lower adjusting block assemblies are arranged on the first test base, and the lower adjusting block assemblies comprise a plurality of lower adjusting blocks arranged in sequence and decreasing in size in sequence. One lower adjusting block is connected with the first test base, and the plurality of lower adjusting block assemblies cooperate to clamp the lower end of the test sample. A plurality of upper adjusting block assemblies are arranged on the upper fixed frame, and the upper adjusting block assemblies comprise a plurality of upper adjusting blocks arranged in sequence and decreasing in size in sequence. One upper adjusting block is connected with the upper fixed frame, and the plurality of upper adjusting block assemblies cooperate to clamp the upper end of the test sample.

[0015] In an optional embodiment, a second guide rail is further included, and the second guide rail is arranged on both sides of the first direction of the first test base; and the second guide rail is fixedly arranged on the device main body.

[0016] The first test base of the rock mechanics dynamic three-directional shearing device provided by the application can place a test sample, the test sample is moved to the lower side of the normal pressure assembly through the first guide rail, the upper end surface of the test sample is pressed by the normal pressure assembly, the upper half of the test sample is clamped by the second side pressure assembly and the third side pressure assembly, the first test base is pressed by the first side pressure assembly, and the lower half of the test sample is pressed by the first test base; that is, the first direction cyclic loading, the second direction cyclic loading, and the normal cyclic loading can be realized independently, and the dynamic three-directional shearing is realized. The mechanical state of the rock body under load in the real earthquake situation is met, the common loading dynamic waveforms including the sine wave, the square wave, the program wave, the variable frequency wave, and the variable amplitude wave can be loaded, and the multi-directional loading can be decoupled. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 A structural schematic view of a rock mechanics dynamic three-way shearing device provided by an embodiment of the present application is shown in FIG. 1; Figure 2 A structural schematic view of a longitudinal section of the rock mechanics dynamic three-way shearing device is shown in FIG. 2; Figure 1 Figure 3 A structural schematic view of another angle of the longitudinal section of the rock mechanics dynamic three-way shearing device is shown in FIG. 3; Figure 1 A structural schematic view of a first test base of the rock mechanics dynamic three-way shearing device is shown in FIG. 4; Figure 4 Figure 1 A structural schematic view of a lower adjusting block assembly and an upper assembly sleeve assembly of the first test base is shown in FIG. 5; Figure 5 A structural schematic view of a shearing box of the rock mechanics dynamic three-way shearing device is shown in FIG. 6; Figure 4 A structural schematic view of another angle of the shearing box is shown in FIG. 7; Figure 6 Figure 1 A structural schematic view of an upper assembly sleeve assembly and a lower assembly sleeve assembly of the shearing box is shown in FIG. 8; Figure 7 A structural schematic view of another angle of the position relationship between the upper assembly sleeve assembly and the lower assembly sleeve assembly is shown in FIG. 9. Figure 6 Figure 8 Figure 6 Figure 9 Figure 8

[0019] ​​​​​​​​Icon: 100-device body; 200-first guide rail; 300-first test base; 400-test sample; 500-normal pressure static oil cylinder; 600-normal pressure dynamic oil cylinder; 700-normal load sensor; 800-normal force transmission device; 900-normal displacement sensor; 110-third dynamic oil cylinder; 120-third load sensor; 130-third friction bearing; 140-third force transmission device; 150-second static oil cylinder; 160-second dynamic oil cylinder; 170-second load sensor; 180-second friction bearing; 190-second force transmission device; 210-force transmission piece; 220-first static oil cylinder; 230-first dynamic oil cylinder; 240-first load sensor; 250-first force transmission device; 260-fine adjustment block; 270-first side pressure assembly; 280-second side pressure assembly; 290-first displacement sensor; 310-normal pressure assembly; 320-fourth friction bearing; 330-upper adjustment block assembly; 340-lower adjustment block assembly; 350-upper box body; 360-lower box body; 370-upper assembly sleeve assembly; 380-lower assembly sleeve assembly; 390-test cavity. DETAILED DESCRIPTION

[0020] The terms "first", "second", "third", and the like, are used only to distinguish descriptions, and do not indicate the arrangement number, and cannot be understood as indicating or implying relative importance.

[0021] In addition, the terms "horizontal", "vertical", "overhanging", and the like, do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0022] In the description of the present application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", and the like, indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0023] In the description of the present application, unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements.

[0024] The technical solutions of the present application will be described clearly and completely below with reference to the drawings.

[0025] With reference to Figures 1-3 The present application provides a rock mechanics dynamic three-way shearing device, which comprises a device main body 100, the device main body 100 comprises a first guide rail 200, a first test base 300 is arranged on the first guide rail 200, and the first test base 300 is used for placing a test sample 400; A normal pressure assembly 310 is arranged on the device main body 100, and the normal pressure assembly 310 abuts against an upper end surface of the test sample 400; A first side pressure assembly 270 is arranged at one end of a first direction of the device main body 100, and the first side pressure assembly 270 is connected with the first test base 300; A second side pressure assembly 280 is arranged at one end of a second direction of the device main body 100, and the second side pressure assembly 280 abuts against an upper half of one side of the test sample 400; A third side pressure assembly is arranged at the other end of the second direction of the device main body 100, and the third side pressure assembly abuts against an upper half of the other side of the test sample 400; The first direction is perpendicular to the second direction.

[0026] In some embodiments, the first direction and the second direction are in the same plane, and the pressure direction of the normal pressure assembly 310 is perpendicular to the first direction.

[0027] The normal pressure assembly 310 exerts pressure on the upper end surface of the test sample 400; the test sample 400 is placed on the first test base 300, and the first test base 300 can move along the first guide rail 200; after the first test base 300 is assembled with the test sample 400, when the test sample 400 moves below the normal pressure assembly 310, the second side pressure assembly 280 and the third side pressure assembly can both abut against the upper half of the test sample 400.

[0028] The first side pressure assembly 270 acts on the first test base 300 to exert a force along the first direction on the test sample 400, and the second side pressure assembly 280 and the third side pressure assembly clamp the test sample 400 to exert external pressure forces on opposite sides of the test sample 400.

[0029] The second side pressing assembly 280 has a maximum dynamic loading frequency of 20 Hz and a maximum shear displacement stroke of 125 mm. The second side pressing assembly 280 and the third side pressing assembly act on the upper half of the test sample 400 respectively to realize a cyclic loading in a shear direction. The first side pressing assembly 270 has a maximum dynamic loading frequency of 20 Hz and a maximum shear displacement stroke of 125 mm. The first side pressing assembly 270 is fixed with the lower half of the first test base 300 and moves together with the first guide rail 200 during loading to realize a cyclic loading in a shear direction. The normal pressing assembly 310 has a maximum dynamic loading frequency of 20 Hz and a maximum shear displacement stroke of 100 mm to realize a normal cyclic loading on the test sample 400. The three assemblies can independently load or realize a dynamic three-way shear under the control of a servo control system.

[0030] Referring to Figure 2 In an optional embodiment, the normal pressing assembly 310 comprises, from top to bottom, a normal pressing static oil cylinder 500, a normal pressing dynamic oil cylinder 600, a normal load sensor 700 and a normal force transmission device 800; the normal force transmission device 800 is in abutment with the upper end surface of the test sample 400; A normal shear friction bearing is arranged between the normal load sensor 700 and the normal force transmission device 800. A plurality of normal displacement sensors 900 are arranged on the normal shear friction bearing, and the normal displacement sensors 900 are used for vertical deformation measurement of the test sample 400.

[0031] In some embodiments, the normal pressing static oil cylinder 500 (1500 KN) and the normal pressing dynamic oil cylinder 600 (500 KN); the normal pressing static oil cylinder 500 is outside the device main body 100, and is artificially punched on the outermost side plate to be engaged with the normal pressing dynamic oil cylinder 600 on the inner side through bolts; the normal pressing dynamic oil cylinder 600 is artificially punched on the secondary outer side plate to be fixed on the device main body 100 through bolts.

[0032] The normal pressing dynamic oil cylinder 600 can be used alone or together with the normal pressing static oil cylinder 500. The lower end of the normal pressing dynamic oil cylinder 600 is connected with the normal load sensor 700 through bolts. The lower end of the normal load sensor 700 is fixed with the normal shear friction bearing through bolts, and the normal shear friction bearing is formed by bolts and springs connected with the left and right side plates and the middle cylindrical strip. The normal shear friction bearing acts on the normal force transmission device 800, and the normal force transmission device 800 is a rectangular pressing plate. The normal force transmission device 800 is fixed on the upper surface of the test sample 400 and moves together with the test sample 400 during the test loading to realize dynamic shear. Four normal displacement sensors 900 are arranged outside the normal load sensor 700 to monitor displacement and servo control.

[0033] The normal pressure applying assembly 310 applies cyclic reciprocating normal load to the test sample 400 in cooperation with the first side pressure applying assembly 270, the second side pressure applying assembly 280 and the third side pressure applying assembly under servo control.

[0034] Referring to Figure 3 In an optional embodiment, one end of the first side pressure applying assembly 270 is connected with an upper fixed frame, the upper fixed frame is provided with oppositely arranged force transmission members 210, and one end of the force transmission members 210 abuts against the upper half of the test sample 400; The second side pressure applying assembly 280 and the third side pressure applying assembly each abut against one of the force transmission members 210; The second side pressure applying assembly 280 comprises a second static oil cylinder 150, a second dynamic oil cylinder 160, a second load sensor 170, a second shear friction bearing 180 and a second force transmission device 190 arranged in sequence, and the second force transmission device 190 abuts against the corresponding force transmission member 210; The force transmission member 210 is provided with a plurality of second displacement sensors for measuring the deformation of the test sample 400 in the second direction.

[0035] The second static oil cylinder 150 is outside the device main body 100, and is artificially bored on the outside side plate and engaged with the second dynamic oil cylinder 160 on the inside via bolts. The second dynamic oil cylinder 160 can be used alone or together with the second static oil cylinder 150. One end of the second dynamic oil cylinder 160 is connected with the second load sensor 170, and two second displacement sensors are arranged outside the second dynamic oil cylinder 160 and the second load sensor 170, and are connected via bolts. One end of the second load sensor 170 is fixedly connected with the second shear friction bearing 180 via bolts, and the second shear friction bearing 180 is formed by left and right side plates and a middle cylindrical strip connected via bolts and springs. The second shear friction bearing 180 acts on the rectangular cuboid-shaped second force transmission device 190, and the second force transmission device 190 acts on the upper half of the test sample 400 via the artificial opening of the device main body 100. A sliding bearing is arranged at the contact part of the second force transmission device 190 and the artificial opening to reduce the friction. In order to realize dynamic shear, a shear friction bearing is also arranged at the upper half of the test sample 400 in the first direction, and the side plate close to the test sample 400 moves together with the test sample 400 during loading, and the other side is fixed.

[0036] In an optional embodiment, the third side pressure applying assembly comprises a third dynamic oil cylinder 110, a third load sensor 120, a third shear friction bearing 130 and a third force transmission device 140 arranged in sequence, and the third force transmission device 140 abuts against the corresponding force transmission member 210.

[0037] In the second direction, the second side pressing assembly 280 and the third side pressing assembly are controlled in coordination, and in a cycle period, a cycle load can be achieved by repeated alternation. After one side pressing assembly is loaded in the positive direction, it quickly tends to 0 under the servo control, and then is loaded in the negative direction. The loading process of the other side pressing assembly is opposite to the former, and the loading mode of "one in and one out" is achieved. When the initial stress is 0, after a short time of loading, the cycle stress of the test sample 400 quickly reaches the target cycle stress value and remains stable. When the strain or stress of the test sample 400 reaches the breaking value, the control system quickly responds and stops loading. The design based on the two side pressing assemblies makes the shear device more easily servo-controlled in the dynamic shear process, and the stress state of the sample is more reasonable.

[0038] In the optional embodiment, the first side pressing assembly 270 comprises a first static oil cylinder 220, a first dynamic oil cylinder 230, a first load sensor 240 and a first force transmission device 250 arranged in sequence, and the first force transmission device 250 is connected with the first test base 300. The first force transmission device 250 is provided with a first displacement sensor 290 for measuring the deformation of the test sample 400 in the first direction.

[0039] The first static oil cylinder 220 is outside the device main body 100, and is artificially formed on the outside side plate and is engaged with the first dynamic oil cylinder 230 on the inside through bolts. The first dynamic oil cylinder 230 can be used alone or together with the first static oil cylinder 220. The negative end of the first dynamic oil cylinder 230 is connected with the first load sensor 240, and two first displacement sensors 290 are arranged outside the first load sensor 240 and the first dynamic oil cylinder 230, and are connected through bolts. The negative end of the first load sensor 240 is connected with the first force transmission device 250 below through a bolt, the first force transmission device 250 acts on the lower half of the test sample 400, and the first force transmission device 250 is "L"-shaped with the front small and the rear large.

[0040] In some embodiments, the rock mechanics dynamic three-way shear device has a first displacement sensor 290, a second displacement sensor and a first displacement sensor 290; generally has four first displacement sensors 290, two second displacement sensors and two first displacement sensors 290; eight displacement sensors are all magnetic expansion displacement sensors, the displacement range is 250mm, the resolution is 0.5μm, and the displacement accuracy is ±0.3%FS; four normal displacement sensors 900 are arranged on the normal shear bearing; the normal displacement sensor 900 is used for measuring the deformation in the normal direction, four average values are used to control the normal deformation, and the normal deformation measurement range is ±5mm.

[0041] The second displacement sensor and the first displacement sensor 290 are arranged in the first direction and the second direction respectively; two deformation measurement points are arranged, and the deformation measurement range is ±100 mm.

[0042] In the optional embodiment, the upper fixing frame comprises a first side blocking plate, a second side blocking plate, a third side blocking plate and a fourth side blocking plate; the first side blocking plate and the third side blocking plate are arranged oppositely, and the first side blocking plate and the third side blocking plate are both provided with a force transmission member 210; The second side blocking plate and the fourth side blocking plate are arranged oppositely, and a fourth shear friction bearing 320 is arranged on the inner side wall of the second side blocking plate and the fourth side blocking plate; the fourth shear friction bearing 320 abuts against the upper half of the test sample 400; The second side blocking plate is provided with a lower notch, and the second force transmission device 190 passes through the lower notch and is connected with the first test base 300; The first test base 300 has four limiting plates, and the four limiting plates are arranged in a rectangular shape on the first test base 300; A fine adjustment block 260 is arranged on the first test base 300, and the fine adjustment block 260 is used for fixing the test sample 400 on the first test base 300.

[0043] In some embodiments, the first test base 300 has four limiting plates, and the four limiting plates form a fixed region, and the test sample 400 is placed in the fixed region; in order to firmly fix the test sample 400, a fine adjustment block 260 is inserted between the test sample 400 and the limiting plate; the fine adjustment block 260 comprises two adjusting plates, and a wedge-shaped block is inserted between the two adjusting plates; by adjusting the depth of the wedge-shaped block inserted between the two adjusting plates, the distance between the two adjusting plates is adjusted, and then the test sample 400 is firmly fixed on the first test base 300.

[0044] The upper fixing frame is connected with the first side pressing assembly 270, two fourth shear friction bearings 320 are arranged in the upper fixing frame, and the fourth shear friction bearings 320 abut against the test sample 400; that is, two sides of the rectangular test sample 400 abut against the fourth shear friction bearings, and the other two sides abut against the third shear friction bearing 130 and the second shear friction bearing 180 through the force transmission member 210 respectively.

[0045] Referring to Figure 6 , Figure 7 , Figure 8 and Figure 9In an optional embodiment, the first test base 300 is provided with a shearing box, which comprises an upper box body 350 and a lower box body 360, the upper box body 350 is in abutment with the force transmitting member 210, and the lower box body 360 is fixedly arranged on the first test base 300. An upper assembly hole is arranged in the upper box body 350, and a lower assembly hole corresponding to the upper assembly hole is arranged on the lower box body 360. An upper assembly sleeve assembly 370 is arranged in the upper assembly hole, and a lower assembly sleeve assembly 380 is arranged in the lower assembly hole, and the upper assembly sleeve assembly 370 and the lower assembly sleeve assembly 380 form a test cavity 390 for placing a test sample 400. Referring to Figure 8 and Figure 9 In an optional embodiment, the upper assembly sleeve assembly 370 comprises a plurality of upper assembly sleeves arranged in sequence, the lower assembly sleeve assembly 380 comprises a plurality of lower assembly sleeves arranged in sequence, and each upper assembly sleeve can form a test cavity 390 with one lower assembly sleeve.

[0046] In some embodiments, in order to test other shapes of samples, such as cylindrical test samples 400, a shearing box is arranged on the first test base 300, an upper assembly hole is arranged on the upper box body 350 of the shearing box, a lower assembly hole is arranged on the lower box body 360, an upper assembly sleeve assembly 370 is arranged in the upper assembly hole, and the upper assembly sleeve assembly 370 comprises one or more upper assembly sleeves; when the upper assembly sleeve assembly 370 comprises a plurality of upper assembly sleeves, the plurality of upper assembly sleeves are arranged in sequence, and adjacent two upper assembly sleeves are connected by screws.

[0047] The upper assembly sleeve assembly 370 and the lower assembly sleeve assembly 380 are similar in structure, and the upper assembly sleeve and the lower assembly sleeve can form a plurality of test cavities 390 of different specifications, thereby meeting the fixation of test samples 400 of different specifications.

[0048] Referring to Figure 4 and Figure 5 In an optional embodiment, the first test base 300 is provided with a plurality of lower adjusting block assemblies 340, and the lower adjusting block assembly 340 comprises a plurality of lower adjusting blocks connected in sequence and gradually decreasing in size. One of the lower adjusting blocks is connected with the first test base 300, and the plurality of lower adjusting block assemblies 340 cooperate to clamp the lower end of the test sample 400. The upper fixing frame is provided with a plurality of upper adjusting block assemblies 330, and the upper adjusting block assembly 330 comprises a plurality of upper adjusting blocks connected in sequence and gradually decreasing in size. The upper adjusting blocks are connected with the upper fixed frame, and the upper adjusting block assemblies 330 are matched to clamp the upper end of the test sample 400.

[0049] In some embodiments, in order to enable the first test base 300 to place test samples 400 of multiple different specifications, the first test base 300 is generally rectangular, and a lower adjusting assembly is arranged on the side of the side blocking plate of the first test base 300, the lower adjusting assembly comprising one or more lower adjusting blocks, and the lower adjusting blocks of the same specification of the multiple lower adjusting assemblies forming a fixed area matched with the test sample 400.

[0050] The device body 100 is provided with multiple upper adjusting block assemblies 330, generally four upper adjusting block assemblies 330 corresponding to four lower adjusting assemblies; the multiple upper adjusting blocks of the upper adjusting block assembly 330 are arranged in sequence, and the multiple upper adjusting blocks of the same specification form a fixed area, and the multiple upper adjusting block assemblies 330 cooperate to fix the upper half of the test sample 400.

[0051] The multiple upper adjusting block assemblies 330 and the multiple lower adjusting assemblies cooperate to enable the fixing of test samples 400 of multiple specifications.

[0052] In an optional embodiment, a second guide rail is further included, and the second guide rail is arranged on both sides of the first direction of the first test base 300; and the second guide rail is fixedly arranged on the device body 100.

[0053] In order to enable the first test base 300 to move more accurately, a second guide rail is further arranged on the basis of the first guide rail 200; generally, three first guide rails 200 are arranged on the support surface, and two second guide rails are arranged on both sides of the first direction of the first test base 300; thereby effectively improving the accuracy and stability of the movement of the first test base 300.

[0054] The first test base 300 of the rock mechanics dynamic three-way shearing device provided by the application can place a test sample 400, and the test sample 400 is moved to the lower side of the normal pressure assembly 310 through the first guide rail 200, the upper end surface of the test sample 400 is pressed by the normal pressure assembly 310, the upper half of the test sample 400 is clamped by the second side pressure assembly 280 and the third side pressure assembly, the first test base 300 is pressed by the first side pressure assembly 270, and the lower half of the test sample 400 is pressed by the first test base 300; that is, the first direction cyclic loading, the second direction cyclic loading, and the normal cyclic loading can be realized independently, thereby realizing dynamic three-way shearing. The mechanical state of the rock body under load in the real earthquake situation is met, and the loading of common loading dynamic waveforms including sine wave, square wave, program wave, variable frequency wave, and variable amplitude wave can be realized, and the multi-way loading can be decoupled.

[0055] The servo control system of the dynamic triaxial shearing device in rock mechanics monitors the actual output value in real time through feedback elements, compares it with the input target signal, and obtains the deviation value. Based on the deviation value measured by the displacement sensor, the controller calculates the control quantity of the loading signal according to a certain control algorithm (PID), and then drives the actuator to make the output as close as possible to the input target signal, thereby achieving precise control.

[0056] It can quickly track changes in command signals and reach a stable state in a short time. It has good dynamic performance, realizes cyclic dynamic loading in the normal direction, and can control displacement and load in all three directions.

[0057] This dynamic triaxial shearing device for rock mechanics achieves triaxial dynamic shearing; its high-precision servo control system and sensors can control and record the stress conditions of the sample, realistically simulating the loading conditions of rock and soil under seismic loading. It accurately measures the mechanical parameters of rock and soil under multiple seismic loading conditions; reveals the instability and failure mechanism of rock and soil; and provides theoretical basis and support for disaster prediction and prevention.

[0058] Prepare test specimens according to the test requirements. For in-situ specimens, blocky rock samples can be collected directly from the rock mass and then processed into the required size and shape. For remolded specimens, they need to be remolded and compacted according to the specified methods to meet the specified test requirements and size and shape.

[0059] Check that all components of the shear apparatus are functioning properly, including the shearing system, servo control system, sensors, and shear chamber, ensuring that each system is in normal working order and the instrument accuracy meets requirements. Remove the shear chamber, install the prepared sample inside, and move it back into the shear chamber, adjusting the bolts to ensure full contact between the sample and the shearing device. Activate the servo control system, applying preload to the sample in three directions via hydraulic cylinders; the magnitude of the preload is determined according to the test requirements. After the preload stabilizes, apply tension / compression at a certain rate in the normal loading direction, primary shear direction, and secondary shear direction until the sample fails under shear stress. During this process, the system records the triaxial stress, strain, displacement, and load. Deformation sensors record the triaxial displacement data.

[0060] After the experiment, the experimental data and files are saved and exported, then imported into relevant software for analysis. Stress-strain curves are plotted, and soil shear strength parameters, such as the internal friction angle and cohesion, are determined based on the curve characteristics.

[0061] Clean the testing equipment and site: Remove the sample from the moving shear box, shut down the equipment, and clean and maintain the equipment. Clean and tidy the testing site.

[0062] The dynamic shear stress curve of different rock mass will be different due to the internal composition, structure, tectonic and external temperature, confining pressure, loading rate, etc. Through the analysis of these stress curves, the mechanical properties and deformation mechanism of rock mass under dynamic shear conditions can be understood in depth.

[0063] The device can apply specific shear stress in the initial stage of the test through servo control, and present the deformation characteristics of rock mass under the action of shear force through shear stress-strain diagram in real time, effectively reveal the shear resistance performance and failure mechanism of the material; the loading of different strain rates can obtain the strength-strain rate curve, and intuitively show the change trend of the strength of the material under different deformation rates; the cyclic loading function can simulate the mechanical properties of rock mass under cyclic load, and provide data support for analyzing the influence of earthquake on rock mass; finally, the relationship between peak shear strength and cyclic shear number under different normal stress conditions is analyzed.

[0064] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A dynamic triaxial shear device for rock mechanics, characterized in that, The device comprises a device body (100), the device body (100) comprises a first guide rail (200), a first test base (300) is arranged on the first guide rail (200), and the first test base (300) is used for placing a test sample (400); A normal pressure assembly (310) is arranged on the device body (100), and the normal pressure assembly (310) abuts against an upper end surface of the test sample (400); A first side pressure assembly (270) is arranged at one end of a first direction of the device body (100), and the first side pressure assembly (270) is connected with the first test base (300); A second side pressure assembly (280) is arranged at one end of a second direction of the device body (100), and the second side pressure assembly (280) abuts against an upper half of one side of the test sample (400); A third side pressure assembly is arranged at the other end of the second direction of the device body (100), and the third side pressure assembly abuts against an upper half of the other side of the test sample (400); The first direction is perpendicular to the second direction.

2. The dynamic triaxial shear device for rock mechanics of claim 1, wherein, The normal pressure assembly (310) comprises, from top to bottom, a normal pressure static oil cylinder (500), a normal pressure dynamic oil cylinder (600), a normal load sensor (700) and a normal force transmission device (800); the normal force transmission device (800) abuts against the upper end surface of the test sample (400); A normal shear bearing is arranged between the normal load sensor (700) and the normal force transmission device (800); A plurality of normal displacement sensors (900) are arranged on the normal shear bearing, and the normal displacement sensors (900) are used for vertical deformation measurement of the test sample (400).

3. The dynamic triaxial shear apparatus for rock mechanics of claim 1, wherein, One end of the first side pressure assembly (270) is connected with an upper fixed frame, the upper fixed frame is provided with oppositely arranged force transmission members (210), and one end of the force transmission members (210) abuts against the upper half of the test sample (400); The second side pressure assembly (280) and the third side pressure assembly both abut against one force transmission member (210); The second side pressure assembly (280) comprises, in sequence, a second static oil cylinder (150), a second dynamic oil cylinder (160), a second load sensor (170), a second shear bearing (180) and a second force transmission device (190), and the second force transmission device (190) abuts against the corresponding force transmission member (210); A plurality of second displacement sensors are arranged on the force transmission member (210), and the second displacement sensors are used for measuring the deformation of the test sample (400) in the second direction.

4. The dynamic triaxial shear device for rock mechanics of claim 3, wherein, The third side pressure assembly comprises, in sequence, a third dynamic oil cylinder (110), a third load sensor (120), a third shear bearing (130) and a third force transmission device (140), and the third force transmission device (140) abuts against the corresponding force transmission member (210).

5. The dynamic triaxial shear apparatus for rock mechanics of claim 3, wherein, The first side pressing assembly (270) comprises a first static oil cylinder (220), a first dynamic oil cylinder (230), a first load sensor (240) and a first force transmission device (250) arranged in sequence, and the first force transmission device (250) is connected with the first test base (300). The first force transmission device (250) is provided with a first displacement sensor (290) for measuring the deformation of the test sample (400) in the first direction.

6. The dynamic triaxial shear device for rock mechanics of claim 5, wherein, The upper fixed frame comprises a first side blocking plate, a second side blocking plate, a third side blocking plate and a fourth side blocking plate; the first side blocking plate and the third side blocking plate are oppositely arranged, and the first side blocking plate and the third side blocking plate are both provided with a force transmission member (210); The second side blocking plate and the fourth side blocking plate are oppositely arranged, and a fourth shear friction bearing (320) is arranged on the inner side wall of the second side blocking plate and the fourth side blocking plate; the fourth shear friction bearing (320) abuts against the upper half of the test sample (400); A lower notch is arranged on the second side blocking plate, and the second force transmission device (190) is connected with the first test base (300) through the lower notch; The first test base (300) has four limiting stop plates arranged in a rectangular shape on the first test base (300); A fine adjustment block (260) is arranged on the first test base (300), and the fine adjustment block (260) is used for fixing the test sample (400) on the first test base (300).

7. The dynamic triaxial shear apparatus for rock mechanics of claim 3, wherein, A shear box is arranged on the first test base (300), the shear box comprises an upper box body (350) and a lower box body (360), the upper box body (350) abuts against the force transmission member (210), and the lower box body (360) is fixedly arranged on the first test base (300); An upper assembly hole is arranged in the upper box body (350), and a lower assembly hole corresponding to the upper assembly hole is arranged on the lower box body (360); An upper assembly sleeve assembly (370) is arranged in the upper assembly hole, and a lower assembly sleeve assembly (380) is arranged in the lower assembly hole, and the upper assembly sleeve assembly (370) and the lower assembly sleeve assembly (380) form a test cavity (390) for placing the test sample (400).

8. The dynamic triaxial shear apparatus for rock mechanics of claim 7, wherein, The upper assembly sleeve assembly (370) comprises a plurality of upper assembly sleeves arranged in sequence, and the lower assembly sleeve assembly (380) comprises a plurality of lower assembly sleeves arranged in sequence; and each upper assembly sleeve can form a test cavity (390) with one lower assembly sleeve.

9. The dynamic triaxial shear apparatus for rock mechanics of claim 3, wherein, A plurality of lower adjustment block assemblies (340) are arranged on the first test base (300), and the lower adjustment block assembly (340) comprises a plurality of lower adjustment blocks connected in sequence and decreasing in size; One of the lower adjustment blocks is connected with the first test base (300), and a plurality of lower adjustment block assemblies (340) cooperate to clamp the lower end of the test sample (400); A plurality of upper adjusting block assemblies (330) are arranged on the upper fixed frame, and the upper adjusting block assemblies (330) comprise a plurality of upper adjusting blocks which are sequentially connected and sequentially reduced in size; The upper adjusting blocks are connected with the upper fixed frame at one time, and the plurality of upper adjusting block assemblies (330) cooperate to clamp the upper end of the test sample (400).

10. The dynamic triaxial shear apparatus for rock mechanics of claim 1, wherein, Second guide rails are further included, and the second guide rails are arranged on both sides of the first direction of the first test base (300); and the second guide rails are fixedly arranged on the device main body (100).

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