Fractured rock mass single shear test system and method based on three-way dynamic method

Abstract

The invention relates to a fractured rock mass single shear test system and method based on a three-way dynamic method, and the fractured rock mass single shear test system based on the three-way dynamic method comprises a test host, a hydraulic system, a cooling system, a data acquisition system, a computer control system and a computer control cabinet, the test host comprises a four-column type loading frame, a stacked ring shear box, a z-direction dynamic loading assembly, an x-direction dynamic loading assembly, a y-direction dynamic loading assembly, an x-direction counter-force assembly, a direction counter-force assembly and a transmission guide rail. The device has the beneficial effects that a single shear test of a fractured rock mass sample under a static or dynamic load condition can be realized, the influence of seismic motion multidirectivity on static and dynamic characteristics of the fractured rock mass can be researched, and a slope dynamic instability mechanism can be disclosed.

Description

Technical Field

[0001] The invention relates to the technical field of rock and soil mechanics testing, and in particular to a fractured rock mass single shear testing system and method based on a three-dimensional dynamic method. Background Art

[0002] Fractured rock mass is distributed with intricate and criss-crossing structural planes from macroscopic to microscopic levels. Its mechanical properties depend on the distribution characteristics of the structural planes, such as their length, occurrence, and density. The existence of structural planes makes the strength of rock mass with the same lithology significantly lower than that of intact rock. Especially in the southwestern mountainous areas of my country where strong earthquakes frequently occur, fractured rock mass suffers cumulative losses due to external forces such as earthquakes, which becomes one of the important causes of rock structure instability. These factors directly affect the stability of rock engineering.

[0003] Seismic loads have both dynamic characteristics and obvious cyclic properties. Different from biaxial stress conditions, triaxial stress conditions have a very significant impact on the mechanical properties of fractured rock mass, which is mainly reflected in the impact on the crack expansion mode, failure mode, strength characteristics and permeability. Macroscopically, the strength of fractured rock mass is reduced and the deformation and failure mode is more complex. The shear test device is a key equipment for exploring the shear mechanical properties, failure mechanism and instability and slip mechanism of rock mass. As a special test equipment for rock mass mechanics, the rock direct shear instrument is the basis for studying the static and dynamic characteristics of rock. Its principle is to prefabricate the fracture surface so that it can be destroyed along the prefabricated fracture surface during shearing. However, fractured rock mass has multiple regular or irregular fractures, which makes the strength parameters obtained by the direct shear instrument inconsistent with the actual ones. Therefore, it is necessary to develop a single shear test system specifically for fractured rock mass.

[0004] In summary, the development of a three-dimensional dynamic method for the simple shear test system of fractured rock mass is of great significance for studying the mechanical properties test device of fractured rock mass under multi-directional loads and near-fault pulse earthquake loads. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a fractured rock mass single shear test system and method based on a three-dimensional dynamic method, which can realize the single shear test of fractured rock mass specimens under static or dynamic load conditions, and can study the influence of the multi-directionality of seismic motion on the static and dynamic characteristics of fractured rock mass, which is conducive to revealing the dynamic instability mechanism of slope.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a fractured rock mass single shear test system based on a three-dimensional dynamic method, comprising:

[0008] A test host, the test host comprises a four-column loading frame, a stacking ring shear box, a z-direction dynamic loading component, an x-direction dynamic loading component, a y-direction dynamic loading component, an x-direction reaction force component, a y-direction reaction force component and a conveying guide rail, wherein the x-direction reaction force component, the y-direction reaction force component and the stacking ring shear box are all arranged in the four-column loading frame, the z-direction dynamic loading component is arranged at the top of the four-column loading frame and acts on the stacking ring shear box, the x-direction dynamic loading component and the y-direction dynamic loading component are arranged on the side wall of the four-column loading frame and act on the stacking ring shear box, the y-direction reaction force component is arranged at the bottom of the four-column loading frame, the stacking ring shear box is arranged on the y-direction reaction force component, the x-direction reaction force component is arranged on the inner side wall of the four-column loading frame and acts on the z-direction dynamic loading component, an opening is arranged on one side of the four-column loading frame, the conveying guide rail is arranged at the opening, and the stacking ring shear box can be transported into the frame through the conveying guide rail;

[0009] A hydraulic system and a cooling system, wherein the hydraulic system is used to supply hydraulic oil to the z-direction dynamic loading component, the x-direction dynamic loading component and the y-direction dynamic loading component, and the cooling system is used to cool the hydraulic oil;

[0010] A data acquisition system, the data acquisition system is used to measure and collect loading parameters of the z-direction dynamic loading component, the x-direction dynamic loading component and the y-direction dynamic loading component;

[0011] Computer control system and computer control cabinet, the computer control system is electrically connected to the computer control cabinet, and the z-direction dynamic loading component, the x-direction dynamic loading component and the y-direction dynamic loading component, the hydraulic system, the cooling system and the data acquisition system are all electrically connected to the computer control system.

[0012] Furthermore, the stacking ring shear box includes an upper shear box, a lower shear box, a common stacking ring and a stacking ring with reserved acoustic emission holes. The lower shear box is arranged at the top of the y-direction reaction force component, the stacking ring with reserved acoustic emission holes is arranged at the top of the lower shear box, the common stacking ring is arranged at the top of the stacking ring with reserved acoustic emission holes, the upper shear box is arranged at the top of the common stacking ring, the z-direction dynamic loading component and the y-direction dynamic loading component act on the upper shear box, and the x-direction dynamic loading component acts on the lower shear box.

[0013] Furthermore, the z-direction dynamic loading assembly includes a z-direction oil cylinder, a ball head compression plate, a z-direction pressure head, a horizontal pressure head and a shear pressure head. The z-direction oil cylinder is arranged on the top of the four-column loading frame through a heightened flange and is electrically connected to the computer control system. The shear pressure head is arranged on the top of the upper shear box. A y-direction anti-friction roller is arranged on the top of the shear pressure head. The z-direction pressure head is an inverted groove-shaped structure. The horizontal pressure head is arranged at the bottom center of the z-direction pressure head and is supported on the y-direction anti-friction roller. The ball head compression plate is connected to the working end of the z-direction oil cylinder and abuts against the top of the z-direction pressure head. A block is abutted between the inner side wall of the z-direction pressure head and the side wall of the upper shear box. A dovetail groove baffle is clamped at the bottom of the side wall of the z-direction pressure head, and the dovetail groove baffle abuts against the upper shear box upward.

[0014] Furthermore, the x-direction dynamic loading component includes an x-direction oil cylinder electrically connected to the computer control system, and the side wall of the lower shear box is provided with an x-direction loading reaction force cap, and the working end of the x-direction oil cylinder abuts against the x-direction loading reaction force cap.

[0015] Furthermore, the y-direction dynamic loading component includes a y-direction oil cylinder electrically connected to the computer control system, and the working end of the y-direction oil cylinder acts on the upper shear box.

[0016] Furthermore, the x-direction reaction force assembly is arranged on both sides of the stacked ring shear box, the x-direction reaction force assembly includes an x-direction reaction force column and an x-direction reaction force device, the x-direction reaction force device includes an oil pressure buffer, a top plate, a z-direction limit seat, a reaction flange, a reaction pad, a stop column and a z-direction anti-friction roller, the reaction flange is arranged on the inner wall of the four-column loading frame, the z-direction limit seat is vertically arranged on the reaction flange through the reaction pad, the two ends of the x-direction reaction column are respectively connected to the inner wall of the four-column loading frame and the z-direction limit seat, the upper and lower ends of the z-direction limit seat are respectively provided with a top plate and a stop column, a plurality of z-direction anti-friction rollers arranged side by side in the vertical direction are rollingly provided on the z-direction limit seat between the top plate and the stop column, the z-direction anti-friction rollers are in rolling contact with the z-direction pressure head, and the oil pressure buffer is arranged on the top plate and acts on the z-direction anti-friction rollers.

[0017] Furthermore, the y-direction reaction force assembly includes a shear box tray and an x-direction anti-friction roller. The shear box tray is arranged at the bottom of the four-column loading frame, the x-direction anti-friction roller is arranged at the top of the shear box tray, and the lower shear box is supported on the x-direction anti-friction roller.

[0018] Furthermore, the data acquisition system includes a z-direction magnetostrictive displacement sensor, an x-direction magnetostrictive displacement sensor, a y-direction magnetostrictive displacement sensor, a shear plate load sensor, and a Foran load sensor electrically connected to the computer control system. The z-direction magnetostrictive displacement sensor, the x-direction magnetostrictive displacement sensor, and the y-direction magnetostrictive displacement sensor are sequentially arranged at the fixed end of the z-direction oil cylinder, the fixed end of the x-direction oil cylinder, and the fixed end of the y-direction oil cylinder. The shear plate load sensor is arranged at the working end of the z-direction oil cylinder and is connected to the ball head compression plate through a connecting cap. The Foran load sensor is arranged at the working end of the x-direction oil cylinder and the working end of the y-direction oil cylinder. The Foran load sensor at the working end of the x-direction oil cylinder is abutted against the x-direction loading reaction force cap, and the Foran load sensor at the working end of the y-direction oil cylinder is connected to the horizontal pressure head through a connecting cap.

[0019] Furthermore, based on the above-mentioned fractured rock mass single shear test system, the present invention also provides a fractured rock mass single shear test method, comprising the following steps:

[0020] S1. Turn on the machine and check whether all equipment and instruments are normal;

[0021] S2, place the lower shear box on the x-direction anti-friction roller in the shear box tray, then place the sample in the middle of the lower shear box, then stack the reserved acoustic emission hole stacking ring and the ordinary stacking ring on the top of the lower shear box in sequence, finally place the upper shear box on the top of the ordinary stacking ring, and place the shear pressure head and the y-direction anti-friction roller on the top of the upper shear box to complete the assembly and sample loading of the stacked ring shear box;

[0022] S3: After the sample is loaded, the stacked ring shear box is transported to the bottom of the z-direction pressure head through the conveying guide rail, and the z-direction oil cylinder is controlled by the computer control system to drive the z-direction pressure head to press down the y-direction anti-friction roller to apply an initial normal force to the stacked ring shear box. Then, the computer control system simultaneously controls the x-direction oil cylinder and the y-direction oil cylinder to respectively support the lower shear box and the upper shear box to apply an initial tangential force to the stacked ring shear box.

[0023] S4. Control the z-axis cylinder, y-axis cylinder and x-axis cylinder through a computer control system to perform a single shear test on the specimen under a constant normal load or a dynamic normal load until the specimen reaches the designed number of cyclic shearing times;

[0024] S5. When the shear displacement of the cylinder reaches the set stroke or number of times, it automatically stops and saves the test data. The computer control system processes and analyzes the data collected by the data acquisition system.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention can realize a simple shear test of a fractured rock sample under a constant normal load and a dynamic normal load. Specifically, the shear test can be performed on the sample through multi-directional dynamic loading in two horizontal and vertical directions. The strain rate and multi-frequency band loading under the action of seismic loads (including pulse loads) can also be realized. Thus, the influence of the multi-directionality of earthquake motion on the dynamic characteristics of fractured rock mass can be studied, which is beneficial to revealing the dynamic instability mechanism of the slope and is of great significance to the theoretical research and engineering design of fractured rock mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the operating principle of the fractured rock mass single shear test system based on the three-way dynamic method in the present invention;

[0028] Figure 2 It is a schematic side elevation diagram of the overall structure of the test host in the present invention;

[0029] Figure 3 It is a front view schematic diagram of the overall structure of the test host in the present invention;

[0030] Figure 4 It is an enlarged schematic diagram of the internal structure of the four-column loading frame of the present invention;

[0031] Figure 5It is a side elevation schematic diagram of the x-direction reaction force device in the present invention.

[0032] In the figure: 1. Computer control cabinet; 2. Computer control system; 3. Hydraulic system; 4. Cooling system; 5. Z-direction dynamic loading assembly; 6. X-direction dynamic loading assembly; 7. Y-direction dynamic loading assembly; 8. Z-direction magnetostrictive displacement sensor; 9. Z-direction oil cylinder; 10. High flange; 11. Lifting ring; 12. Fastening cover; 13. Four-column loading frame; 16. Z-direction pressure head; 15. X-direction oil cylinder; 16. Conveying guide rail; 17. X-direction magnetostrictive displacement sensor; 18. Y-direction magnetostrictive displacement sensor 19, y-axis oil cylinder; 20, stacked ring shear box; 21, shear plate load sensor; 22, connection cover; 23, ball head compression plate; 24, z-axis limit seat; 25, horizontal pressure head; 26, Fulun load sensor; 27, stopper; 28, dovetail groove baffle; 29, ordinary stacked ring; 30, lower shear box; 31, shear box tray; 32, x-axis loading reaction cover; 33, reserved acoustic emission hole stacked ring; 34, x-axis reaction column; 35, upper shear box; 36, shear pressure head; 37, y-axis anti-friction needle roller. 38, hydraulic buffer; 39, top plate; 40, reaction flange; 41 reaction pad; 42, stopper column; 43, z-axis anti-friction needle roller. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0034] like Figure 1 to Figure 4 As shown, a fractured rock mass single shear test system based on a three-way dynamic method includes a test host, a hydraulic system 3, a cooling system 4, a data acquisition system, a computer control system 2 and a computer control cabinet 1.

[0035] The test host includes a four-column loading frame 13, a stacked ring shear box 20, a z-direction dynamic loading assembly 5, an x-direction dynamic loading assembly 6, a y-direction dynamic loading assembly 7, an x-direction reaction assembly, a y-direction reaction assembly and a conveying guide rail 16. The two ends of the columns of the four-column loading frame 13 are connected with fastening caps 12, and the frame is fastened together as a whole through the fastening caps 12. A lifting ring 11 is fixed on the top of the four-column loading frame 13 for easy lifting; the x-direction reaction assembly, the y-direction reaction assembly and the stacked ring shear box 20 are all arranged in the four-column loading frame 13; the z-direction dynamic loading assembly 5 is arranged on the top of the four-column loading frame 13, and is used to apply a normal force to the stacked ring shear box 20; the x-direction dynamic loading assembly 6 and the y-direction dynamic loading assembly 7 are arranged on the side wall of the four-column loading frame 13. , used to apply tangential force to the stacked ring shear box 20; the y-direction reaction force component is arranged at the bottom of the four-column loading frame 13, and the stacked ring shear box 20 is arranged on the y-direction reaction force component; the x-direction reaction force component is arranged on the inner wall of the four-column loading frame 13 and acts on the z-direction dynamic loading component 5; an opening is arranged on one side of the four-column loading frame 13, and a conveying guide rail 16 is arranged at the opening. The conveying guide rail 16 can adopt a sliding structure composed of an existing slider and a slide rail, so that the stacked ring shear box 20 can be transported to the frame through the conveying guide rail 16 under the sliding cooperation of the slider and the slide rail.

[0036] The sample is placed in the stacked ring shear box 20, and then the normal force is applied to the stacked ring shear box 20 by controlling the z-direction dynamic loading component 5, and the tangential force is applied to the stacked ring shear box 20 by the x-direction dynamic loading component 6 and the y-direction dynamic loading component 7, and then the cyclic shear force is applied to the sample by the z-direction dynamic loading component 5, the x-direction dynamic loading component 6, and the y-direction dynamic loading component 7 to realize the single shear test of the sample. The computer control system 2 is electrically connected to the computer control cabinet 1, and the z-direction dynamic loading component 5, the x-direction dynamic loading component 6, and the y-direction dynamic loading component 7, the hydraulic system 3, the cooling system 4, and the data acquisition system are all electrically connected to the computer control system 2; the hydraulic system 3 is used to provide hydraulic oil to the z-direction dynamic loading component 5, the x-direction dynamic loading component 6, and the y-direction dynamic loading component 7; the cooling system 4 is used to cool the hydraulic oil to prevent the hydraulic oil from rapidly heating up during the rapid and dynamic disturbance shearing process, which affects the normal operation of the equipment; the data acquisition system is used to measure and collect the loading parameters of the z-direction dynamic loading component 5, the x-direction dynamic loading component 6, and the y-direction dynamic loading component 7. During the test, the computer control system 2 uniformly controls and coordinates the z-direction dynamic loading component 5, the x-direction dynamic loading component 6, the y-direction dynamic loading component 7, the hydraulic system 3, the cooling system 4, and the data acquisition system. After the test, the computer control system 2 processes and analyzes the data collected by the data acquisition system, and then obtains the test results based on the data.

[0037] like Figure 2 , Figure 4As shown, the stacking ring shear box 20 includes an upper shear box 35, a lower shear box 30, a common stacking ring 29 and a stacking ring 33 with reserved acoustic emission holes. The lower shear box 30 is arranged at the top of the y-direction reaction force component, the stacking ring 33 with reserved acoustic emission holes is arranged at the top of the lower shear box 30, the common stacking ring 29 is arranged at the top of the stacking ring 33 with reserved acoustic emission holes, the upper shear box 35 is arranged at the top of the common stacking ring 29, the z-direction dynamic loading component 5 and the y-direction dynamic loading component 7 act on the upper shear box 35, and the x-direction dynamic loading component 6 acts on the lower shear box 30.

[0038] Four jacks are provided on the top of the lower shear box 30, and holes corresponding to the jacks are also provided on the ordinary stacking ring 29 and the stacking ring 33 with reserved sound emission holes. When placing the ordinary stacking ring 29 and the stacking ring 33 with reserved sound emission holes, the four guide columns can be inserted into the four jacks respectively, and then the stacking rings are successively put on the guide columns through the holes on the stacking rings, thereby completing the stacking of the ordinary stacking ring 29 and the stacking ring 33 with reserved sound emission holes, and finally the guide columns can be removed.

[0039] like Figure 4 As shown, the z-direction dynamic loading assembly 5 includes a z-direction oil cylinder 9, a ball head compression plate 23, a z-direction pressure head 14, a horizontal pressure head 25 and a shearing pressure head 36. The z-direction oil cylinder 9 is arranged on the top of the four-column loading frame 13 through a heightened flange 10 and is electrically connected to the computer control system 2; the shearing pressure head 36 is arranged on the top of the upper shear box 35, and a y-direction anti-friction roller 37 is arranged on the top of the shearing pressure head 36. The z-direction pressure head 14 is an inverted groove-shaped structure, and the horizontal pressure head 25 is arranged at the bottom center of the z-direction pressure head 14 and supported on the y-direction anti-friction roller 37. The y-direction anti-friction roller 37 can reduce the friction resistance generated when the upper shear box 35 is sheared; the ball head compression plate 23 is connected to the working end of the z-direction oil cylinder 9 and is connected to the computer control system 2; the shearing pressure head 36 is arranged on the top of the upper shear box 35, and the y-direction anti-friction roller 37 is arranged on the top of the shearing pressure head 36. The top of the z-direction pressure head 14 abuts; a stopper 27 abuts between the inner side wall of the z-direction pressure head 14 and the side wall of the upper shear box 35, a dovetail groove baffle 28 is provided at the bottom of the side wall of the z-direction pressure head 14, and a dovetail groove is opened on the bottom surface of the side wall of the z-direction pressure head 14, so that the dovetail groove baffle 28 is clamped together with the z-direction pressure head 14 through the dovetail groove, and the dovetail groove baffle 28 abuts against the upper shear box 35 upward, and then the upper shear box 35 is supported by the dovetail groove baffles 28 on both sides of the z-direction pressure head 14 to prevent the upper shear box 35 from tilting during the single shear test.

[0040] The x-direction dynamic loading component 6 includes an x-direction oil cylinder 15 electrically connected to the computer control system 2, and the side wall of the lower shear box is threadedly connected with an x-direction loading reaction force preparation cap 32, and the working end of the x-direction oil cylinder 15 abuts against the x-direction loading reaction force preparation cap 32; the y-direction dynamic loading component 7 includes a y-direction oil cylinder 19 electrically connected to the computer control system 2, and the working end of the y-direction oil cylinder 19 acts on the upper shear box 35.

[0041] In order to keep the shear stress of the theoretical shear surface uniform during the single shear test, an x-direction reaction force assembly is provided on both sides of the stacked ring shear box 20. The x-direction reaction force assembly includes an x-direction reaction force column 34 and an x-direction reaction force device. The x-direction reaction force assembly includes an oil pressure buffer 38, a top plate 39, a z-direction limit seat 24, a reaction force flange 40, a reaction force pad 41, a stop column 42 and a z-direction anti-friction roller 43. The reaction force flange 40 is installed on the inner wall of the four-column loading frame 13, and a reaction force pad 41 is fixed on the reaction force flange 40. The z-direction limit seat 24 is vertically fixed on the reaction force flange 40. On the force pad 41, one end of the x-direction reaction column 34 is fixed to the inner wall of the four-column loading frame 13 through a flange, and the other end of the x-direction reaction column 34 is connected to the z-direction limit seat 24. The upper and lower ends of the z-direction limit seat 24 are respectively fixed with a top plate 39 and a stop column 42. A plurality of z-direction anti-friction rollers 43 arranged side by side in the vertical direction are rollingly provided on the z-direction limit seat 24 between the top plate 39 and the stop column 42. The z-direction anti-friction rollers 43 are in rolling contact with the z-direction pressure head 14, and the oil pressure buffer 38 is installed on the top plate 39 and acts on the z-direction anti-friction rollers 43.

[0042] The y-axis reaction force component includes a shear box tray 31 and an x-axis anti-friction roller. The shear box tray 31 is arranged at the bottom of the four-column loading frame 13, and the x-axis anti-friction roller is arranged at the top of the shear box tray 31. The lower shear box 30 is supported on the x-axis anti-friction roller. The x-axis anti-friction roller can reduce the friction resistance generated by the lower shear box 30 during shearing.

[0043] The data acquisition system includes a z-direction magnetostrictive displacement sensor 8, an x-direction magnetostrictive displacement sensor 17, a y-direction magnetostrictive displacement sensor 18, a shear plate load sensor 21, and a Foran load sensor 26, which are electrically connected to the computer control system 2. The z-direction magnetostrictive displacement sensor 8, the x-direction magnetostrictive displacement sensor 17, and the y-direction magnetostrictive displacement sensor 18 are sequentially installed at the fixed end of the z-direction oil cylinder 9, the fixed end of the x-direction oil cylinder 15, and the fixed end of the y-direction oil cylinder 19, and are used to measure and collect the shear displacement of the oil cylinder; the shear plate load sensor 21 is installed at the working end of the z-direction oil cylinder 9 and is connected to the ball head compression plate 23 through the connecting cap 22, and the shear plate load sensor 21 is used to measure and collect the normal force applied by the z-direction oil cylinder 9; the Foran load sensor 26 is installed at the working end of the x-direction oil cylinder 15 and the working end of the y-direction oil cylinder 19, and the x-direction oil cylinder 9 is connected to the ball head compression plate 23 through the connecting cap 22. The Forlan load sensor 26 at the working end of the cylinder 15 is in contact with the x-direction loading reaction force preparation cap 32, so that the load applied to the x-direction cylinder 15 is transmitted to the lower shear box 30 via the x-direction loading reaction force preparation cap 32, thereby realizing the x-direction tangential force loading on the lower shear box 30; the Forlan load sensor 26 at the working end of the y-direction cylinder 19 is connected to the horizontal pressure head 25 through the connecting preparation cap 22, so that the load applied to the y-direction cylinder 19 is transmitted to the upper shear box 35 via the horizontal pressure head 25, thereby realizing the y-direction tangential force loading on the upper shear box 25. The Forlan load sensor is used to measure and collect the tangential forces applied by the x-direction cylinder 15 and the y-direction cylinder 19.

[0044] In this embodiment, the hydraulic system 3, the cooling system 4, the data acquisition system, the computer control system 2 and the computer control cabinet 1 can all be obtained by existing technical means, and the specific structure and working principle will not be described in detail. The measuring range of the z-axis oil cylinder 9 is 2000kN, the measuring range of the x-axis oil cylinder 15 and the y-axis oil cylinder 19 is 1500kN, and the measuring accuracy of the z-axis oil cylinder 9, the x-axis oil cylinder 15 and the y-axis oil cylinder 19 is 0.05% FS; the measuring range of the z-axis magnetostrictive displacement sensor 8, the x-axis magnetostrictive displacement sensor 17, and the y-axis magnetostrictive displacement sensor 20 is 130mm, and the measuring accuracy is 0.5% FS. The sampling frequency range of normal force, tangential force and shear displacement is 0-1000Hz. By controlling the z-axis cylinder 9, the x-axis cylinder 15 and the y-axis cylinder 19, closed-loop control of functions such as constant normal load, constant normal stiffness, and complex waveform dynamic load single shear can be achieved. The computer control system 2 is integrated with operating software. In any closed-loop process, the operating software first sends instructions to the controller through Ethernet, combines the load and displacement data recorded in real time by the controller, compares the difference between the target value and the actual value, and calculates the corresponding PID output parameters. Then the controller converts the determined PID parameters into electrical signals that act on the servo valve to control the cylinder flow, thereby achieving precise control of a closed-loop process.

[0045] In the hydraulic system 3 of this embodiment, since the static loading cylinder and the dynamic loading actuator have different requirements for hydraulic oil flow and working pressure during execution, in order to accurately control the cylinder, the static loading cylinder and the dynamic loading actuator are driven by different motors and hydraulic pumps. In order to increase the instantaneous flow of the dynamic loading actuator, a hydraulic accumulator is also installed on the hydraulic system 3.

[0046] When a single shear test is performed using the fractured rock mass single shear test system based on the three-way dynamic method, the following steps are included:

[0047] S1. Turn on the machine and check whether all equipment and instruments are normal.

[0048] S2. Place the lower shear box 30 on the x-axis anti-friction roller needle in the shear box tray 31, then place the sample in the middle of the lower shear box 30, and then stack the reserved acoustic emission hole stacking ring 33 and the ordinary stacking ring 29 in sequence on the top of the lower shear box 30, and finally place the upper shear box 35 on the top of the ordinary stacking ring 29, and place the shear pressure head 36 and the y-axis anti-friction roller needle 37 on the top of the upper shear box 35 to complete the assembly and sampling of the stacked ring shear box 20.

[0049] S3: After the sample is loaded, the stacked ring shear box 20 is transported to the bottom of the z-direction pressure head 14 through the conveying guide rail 16, and the z-direction oil cylinder 9 is controlled by the computer control system 2 to drive the z-direction pressure head 14 to press down the y-direction anti-friction roller 37, thereby applying an initial normal force to the stacked ring shear box 20. Then, the x-direction oil cylinder 15 and the y-direction oil cylinder 19 are simultaneously controlled by the computer control system 2 to respectively support the lower shear box 30 and the upper shear box 35, thereby applying an initial tangential force to the stacked ring shear box 20.

[0050] S4. The computer control system 2 controls the z-axis cylinder 11, the y-axis cylinder 19, and the x-axis cylinder 15 to perform a simple shear test on the specimen under constant normal load, constant normal stiffness, or dynamic normal load conditions. The control method can be shear loading using various control methods such as displacement, force, and deformation control.

[0051] When applying a constant normal load, first apply a predetermined normal stress, then apply x- and y-direction loads to 4-5KN simultaneously, and apply shear force in a displacement-controlled manner until the specimen reaches the predetermined shear displacement.

[0052] When performing constant normal stiffness loading, start the built-in constant normal stiffness test function of the software, input the initial normal stress σ0 and the constant normal stiffness coefficient Kn, and then apply shear force to the specimen through the x-axis cylinder 2 and the y-axis cylinder 3 until the specimen reaches the designed shear displacement.

[0053] When loading complex waveform dynamic loads, different measured seismic records can be selected as needed and corrected (for example, baseline correction), and then the corresponding acceleration time history curve record after correction is integrated twice to obtain the displacement time history curve. Finally, the discrete points of the displacement versus time curve are derived and input into the operating software to apply strong seismic wave loads. First, a normal load is applied to the z direction to a preset value, and then a shear load is applied to the x and y directions to preset values ​​at the same time. Different amplitudes and frequencies are changed in the three directions, and shear force is applied in a force-controlled manner until the specimen reaches the corresponding shear displacement or number of times.

[0054] S5. When the shear displacement of the oil cylinder reaches the set stroke or number of times, it automatically stops and saves the test data. The computer control system 2 processes and analyzes the data collected by the data acquisition system.

[0055] The present invention has carried out actual tests through the above-mentioned fractured rock single shear test system based on the three-way dynamic method and the corresponding test method, which can realize the single shear test of fractured rock samples under constant normal load and constant dynamic conditions. The three-way dynamic single shear test can realize multi-directional dynamic loading shear servo dynamic loading in two horizontal and vertical directions, and can also realize strain rate and multi-frequency band loading under the action of seismic load (including pulse load). Therefore, the three-way dynamic single shear cyclic shear test system of the present invention can be used to study the influence of the multi-directionality of earthquake motion on the dynamic characteristics of fractured rock mass, which is conducive to revealing the dynamic instability mechanism of slope, and has important significance for theoretical research and engineering design of fractured rock mass.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fractured rock mass single shear test system based on a three-dimensional dynamic method, characterized in that: include: The test host comprises a four-column loading frame (13), a stacked ring shear box (20), a z-direction dynamic loading component (5), an x-direction dynamic loading component (6), a y-direction dynamic loading component (7), an x-direction reaction force component, a y-direction reaction force component and a conveying guide rail (16), wherein the x-direction reaction force component, the y-direction reaction force component and the stacked ring shear box (20) are all arranged in the four-column loading frame (13), the z-direction dynamic loading component (5) is arranged on the top of the four-column loading frame (13) and acts on the stacked ring shear box (20), and the x-direction dynamic loading component ( 6) and y-direction dynamic loading components (7) are arranged on the side wall of the four-column loading frame (13) and act on the stacked ring shear box (20), the y-direction reaction force component is arranged on the bottom of the four-column loading frame (13), the stacked ring shear box (20) is arranged on the y-direction reaction force component, the x-direction reaction force component is arranged on the inner wall of the four-column loading frame (13) and acts on the z-direction dynamic loading component (5), an opening is arranged on one side of the four-column loading frame (13), a conveying guide rail (16) is arranged at the opening, and the stacked ring shear box (20) can be transported into the frame through the conveying guide rail (16); A hydraulic system (3) and a cooling system (4), wherein the hydraulic system (3) is used to provide hydraulic oil to the z-direction dynamic loading component (5), the x-direction dynamic loading component (6) and the y-direction dynamic loading component (7), and the cooling system (4) is used to cool the hydraulic oil; A data acquisition system, the data acquisition system is used to measure and acquire loading parameters of the z-direction dynamic loading component (5), the x-direction dynamic loading component (6) and the y-direction dynamic loading component (7); A computer control system (2) and a computer control cabinet (1), wherein the computer control system (2) is electrically connected to the computer control cabinet (1), and a z-direction dynamic loading component (5), an x-direction dynamic loading component (6), a y-direction dynamic loading component (7), a hydraulic system (3), a cooling system (4), and a data acquisition system are all electrically connected to the computer control system (2).

2. A fractured rock mass single shear test system based on a three-dimensional dynamic method according to claim 1, characterized in that: The stacking ring shear box (20) comprises an upper shear box (35), a lower shear box (30), a common stacking ring (29) and a stacking ring (33) with a reserved acoustic emission hole, wherein the lower shear box (30) is arranged on the top of a y-direction reaction force component, the stacking ring (33) with a reserved acoustic emission hole is arranged on the top of the lower shear box (30), the common stacking ring (29) is arranged on the top of the stacking ring (33) with a reserved acoustic emission hole, the upper shear box (35) is arranged on the top of the common stacking ring (29), the z-direction dynamic loading component (5) and the y-direction dynamic loading component (7) act on the upper shear box (35), and the x-direction dynamic loading component (6) acts on the lower shear box (30).

3. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 2 is characterized by: The z-direction dynamic loading assembly (5) comprises a z-direction oil cylinder (9), a ball head compression plate (23), a z-direction pressure head (14), a horizontal pressure head (25) and a shear pressure head (36). The z-direction oil cylinder (9) is arranged on the top of the four-column loading frame (13) through a heightened flange (10) and is electrically connected to the computer control system (2). The shear pressure head (36) is arranged on the top of the upper shear box (35). A y-direction anti-friction roller needle (37) is arranged on the top of the shear pressure head (36). The z-direction pressure head (14) is an inverted groove. The invention discloses a shaped structure, wherein a horizontal pressure head (25) is arranged at the bottom center of the z-direction pressure head (14) and supported on the y-direction anti-friction roller needle (37), a ball head compression plate (23) is connected to the working end of the z-direction oil cylinder (9) and abuts against the top of the z-direction pressure head (14), a stopper (27) abuts between the inner side wall of the z-direction pressure head (14) and the side wall of the upper shear box (35), a dovetail groove baffle (28) is clamped at the bottom of the side wall of the z-direction pressure head (14), and the dovetail groove baffle (28) abuts against the upper shear box (35) upwards.

4. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 3 is characterized by: The x-direction dynamic loading component (6) comprises an x-direction oil cylinder (15) electrically connected to the computer control system (2); a side wall of the lower shear box (30) is provided with an x-direction loading reaction force preparation cap (32); and a working end of the x-direction oil cylinder (15) abuts against the x-direction loading reaction force preparation cap (32).

5. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 4 is characterized by: The y-direction dynamic loading component (7) comprises a y-direction oil cylinder (19) electrically connected to the computer control system (2), and the working end of the y-direction oil cylinder (19) acts on the upper shear box (35).

6. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 3 is characterized by: The x-direction reaction force assembly is arranged on both sides of the stacked ring shear box (20), the x-direction reaction force assembly includes an x-direction reaction force column (34) and an x-direction reaction force device, the x-direction reaction force device includes an oil pressure buffer (39), a top plate (38), a z-direction limit seat (24), a reaction force flange (40), a reaction force pad (41), a stop column (42) and a z-direction anti-friction roller (43), the reaction force flange (40) is arranged on the inner wall of the four-column loading frame (13), the z-direction limit seat (24) is vertically arranged on the reaction force flange (40) through the reaction force pad (41), and the x-direction The two ends of the reaction column (34) are respectively connected to the inner wall of the four-column loading frame (13) and the z-direction limit seat (24); the upper end and the lower end of the z-direction limit seat (24) are respectively provided with a top plate (38) and a stop column (42); a plurality of z-direction anti-friction rollers (43) arranged side by side in a vertical direction are rollingly provided on the z-direction limit seat (24) between the top plate (38) and the stop column (42); the z-direction anti-friction rollers (43) are in rolling contact with the z-direction pressure head (14); and a hydraulic buffer (39) is provided on the top plate (38) and acts on the z-direction anti-friction rollers (43).

7. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 3 is characterized by: The y-direction reaction force assembly comprises a shear box tray (31) and an x-direction anti-friction roller. The shear box tray (31) is arranged at the bottom of the four-column loading frame (13), the x-direction anti-friction roller is arranged at the top of the shear box tray (31), and the lower shear box (30) is supported on the x-direction anti-friction roller.

8. The fractured rock mass single shear test system based on the three-dimensional dynamic method according to claim 5, characterized in that: The data acquisition system comprises a z-direction magnetostrictive displacement sensor (8), an x-direction magnetostrictive displacement sensor (17), a y-direction magnetostrictive displacement sensor (18), a shear plate type load sensor (21), and a Forlan type load sensor (26) which are electrically connected to a computer control system (2); the z-direction magnetostrictive displacement sensor (8), the x-direction magnetostrictive displacement sensor (17), and the y-direction magnetostrictive displacement sensor (18) are sequentially arranged at a fixed end of a z-direction oil cylinder (9), a fixed end of an x-direction oil cylinder (15), and a y-direction oil cylinder (19). The shear plate type load sensor (21) is arranged at the working end of the z-direction oil cylinder (9) and is connected to the ball head compression plate (23) through the connection cover (22). The Foran type load sensor (26) is arranged at the working end of the x-direction oil cylinder (15) and the working end of the y-direction oil cylinder (19). The Foran type load sensor (26) at the working end of the x-direction oil cylinder (15) abuts against the x-direction loading reaction force cover (32), and the Foran type load sensor (26) at the working end of the y-direction oil cylinder (19) is connected to the horizontal pressure head (25) through the connection cover (22).

9. A method for single shear testing of fractured rock mass, characterized in that: The following steps are involved: S1. Turn on the machine and check whether all equipment and instruments are normal; S2, placing the lower shear box (30) on the x-axis anti-friction roller needle in the shear box tray (31), then placing the sample in the middle of the lower shear box (30), then stacking the reserved acoustic emission hole stacking ring (33) and the ordinary stacking ring (29) in sequence on the top of the lower shear box (30), and finally placing the upper shear box (35) on the top of the ordinary stacking ring (29), and placing the shear pressure head (36) and the y-axis anti-friction roller needle (37) on the top of the upper shear box (35), completing the assembly and sample loading of the stacking ring shear box (20); S3: After the sample is loaded, the stacked ring shear box (20) is transported to the bottom of the z-direction pressure head (14) through the conveying guide rail (16), and the z-direction oil cylinder (9) is controlled by the computer control system (2) to drive the z-direction pressure head (14) to press down the y-direction anti-friction roller (37), thereby applying an initial normal force to the stacked ring shear box (20), and then the x-direction oil cylinder (15) and the y-direction oil cylinder (19) are simultaneously controlled by the computer control system (2) to respectively support the lower shear box (30) and the upper shear box (35), thereby applying an initial tangential force to the stacked ring shear box (20); S4, controlling the z-axis oil cylinder (9), the y-axis oil cylinder (19), and the x-axis oil cylinder (15) by the computer control system (2) to perform a single shear test on the sample under a constant normal load or a dynamic normal load condition until the sample reaches a designed number of cyclic shear times; S5. When the shear displacement of the oil cylinder reaches the set stroke or number of times, the machine automatically stops and saves the test data. The computer control system (2) processes and analyzes the data collected by the data acquisition system.

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