True triaxial static and dynamic multi-direction and multi-mode combined loading shear device and test method

Abstract

The application discloses a true triaxial static and dynamic multi-direction and multi-mode combined loading shear device and a test method, and belongs to the technical field of geotechnical engineering. The device comprises a normal static and dynamic coaxial active loading module, a shear high-frequency / static low-frequency loading module, a lateral static and dynamic coaxial active loading module, a normal / lateral passive loading module and a true triaxial shear box, each loading module is connected with a corresponding oil cylinder to realize three-direction load application; the test method comprises the following steps: sequentially applying a normal load, a lateral load and a tangential load, then applying a three-direction static load, and finally applying a normal plane disturbance load, a lateral plane disturbance load and a tangential point disturbance load, so as to realize independent application and measurement of three-direction static and dynamic loads of rock mass structural planes, point and plane high and low frequency dynamic and static combined load loading, simulate a complex stress environment, and provide reliable hardware and test means for true triaxial rock mass structural plane multi-direction disturbance shear characteristic research.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering, and particularly relates to a true triaxial static-dynamic multi-directional multi-mode combined loading shear device and test method, which is suitable for simulating the scenario of multi-directional, high-low frequency dynamic-static combined load on rock mass in underground engineering. BACKGROUND

[0002] There are a large number of structural planes (such as joints, fissures) and fault zones in natural rock mass, which greatly change the integrity of the rock mass and have an important influence on the stability of the rock mass in underground engineering (such as tunnel excavation, mine exploitation, underground storage construction). The rock mass in underground engineering is always in a true triaxial stress environment (i.e. the normal, lateral and tangential directions are all subjected to stress), and the load not only includes static stress, but also often accompanies dynamic disturbance (such as blasting vibration, mechanical vibration, seismic wave propagation). Most of the current rock shear test equipment is only suitable for conventional direct shear test, i.e. only considering the stress in the tangential and normal directions, without considering the lateral stress (lateral stress is zero), which is not consistent with the true triaxial stress environment of the structural plane of the rock mass in underground engineering. At present, only a few rock shear devices have the function of rock shear under true triaxial static force conditions, but the function of rock true triaxial shear under dynamic-static combined load has not been perfected, and there is a lack of independent application and independent measurement function of rock structural plane true triaxial same-side same-axis static-dynamic force, and the function of simultaneously applying point-plane high-low frequency dynamic-static combined load to the normal, lateral and tangential directions of the rock mass structural plane cannot be realized.

[0003] In summary, the current rock shear test equipment still has the following deficiencies: it cannot realize the function of simultaneously applying dynamic-static combined disturbance load in the tangential, normal and lateral directions, only a few rock shear devices have the function of rock shear under true triaxial static force conditions, and cannot simultaneously realize the function of applying point-plane high-low frequency dynamic-static combined load to the true triaxial direction of the rock mass structural plane, and the device and function module based on true triaxial static force conditions for further applying disturbance load in each direction are still in the state of being developed.

[0004] Therefore, it is urgent to develop a rock mass structural plane shear device and test method that can simultaneously realize the function of applying dynamic-static combined load in three directions under true triaxial conditions, in order to carry out true triaxial dynamic-static load. SUMMARY

[0005] The present application aims at the deficiencies of the existing rock shear equipment, such as the inability to simulate true triaxial dynamic and static combined load, the lack of three-way static and dynamic independent application and measurement, and the lack of point and surface high and low frequency load application capability, and provides a true triaxial static and dynamic multi-directional and multi-mode combined loading shear device and a test method.

[0006] To achieve the above-mentioned purpose, one of the technical solutions adopted by the present application is to provide a true triaxial static and dynamic multi-directional and multi-mode combined loading shear device, which comprises a ring-shaped frame and an inner frame, and the inner frame is fixed in the ring-shaped frame.

[0007] The normal static and dynamic coaxial active loading module is fixed in the middle vertical through hole of the inner frame, is connected with the normal dynamic and static combined loading oil cylinder fixed in the upper through hole of the ring-shaped frame, and is used for applying static low frequency normal load and high frequency disturbance normal load.

[0008] The shear high frequency loading module is connected with the tangential disturbance loading oil cylinder fixed in the through hole on one side of the ring-shaped frame, and is used for applying high frequency disturbance shear load.

[0009] The shear static low frequency loading module is connected with the tangential static pressure loading oil cylinder fixed in the through hole on the other side of the ring-shaped frame, and is used for applying static low frequency shear load.

[0010] The lateral static and dynamic coaxial active loading module is connected with the lateral dynamic and static combined loading oil cylinder fixed in the through hole on one side of the inner frame, and is used for applying high frequency disturbance lateral load.

[0011] The normal passive loading module is fixed on the lower side of the inner frame, is arranged opposite to the normal static and dynamic coaxial active loading module, and is used for providing normal load reaction.

[0012] The lateral passive loading module is fixed on the other side of the inner frame, is arranged opposite to the lateral static and dynamic coaxial active loading module, and is used for providing lateral load reaction.

[0013] The true triaxial shear box is arranged on the normal passive loading module, is internally provided with a test piece mounting cavity, is used for accommodating a rock test piece and realizing three-way loading, and is provided with a tangential deformation measuring assembly, a lateral deformation measuring assembly and a normal deformation measuring assembly.

[0014] As a further description of the above technical solutions, the central axes of the inner frame and the ring-shaped frame are coincident.

[0015] As a further description of the above technical solution: the normal static-dynamic coaxial active loading module is perpendicular to the horizontal plane and is set directly opposite to the normal dynamic-static combined loading cylinder.

[0016] As a further description of the above technical solution: the shearing high-frequency loading module, the tangential disturbance loading cylinder, the tangential static pressure loading cylinder, and the shearing static low-frequency loading module are arranged facing each other.

[0017] As a further description of the above technical solution: the lateral static-dynamic coaxial active loading module is arranged opposite to the lateral dynamic-static combined loading cylinder.

[0018] The second technical solution adopted in this invention is to provide a test method based on the above-mentioned true triaxial static-dynamic multi-directional multi-mode combined loading shearing device, including the following steps:

[0019] S1. Place the rock specimen in the specimen mounting cavity of the true triaxial shear box, and place the true triaxial shear box on the normal passive loading module;

[0020] S2. Start the static oil source and apply normal preload to the rock specimens sequentially. Lateral preload and shear preload ;

[0021] S3. Apply normal static load to the rock specimen simultaneously using the stress control method. and lateral static load Normal static load on rock specimen The size is Lateral static load The size is ;

[0022] Apply tangential static load only after the normal and lateral static loads have stabilized. Tangential static load on rock specimen The size is ;

[0023] S4. After the tangential static load stabilizes, start the dynamic oil source to apply a normal surface disturbance load to the rock specimen. At this point, the normal surface disturbance load on the rock specimen is The total normal load on the rock specimen is ;

[0024] S5, Disturbance load on the normal surface After being applied for a preset period, the normal surface disturbance load is removed. Lateral surface disturbance loads were applied to the rock specimens. At this point, the lateral surface disturbance load on the rock specimen is The total lateral load on the rock specimen is ;

[0025] S6, Lateral surface disturbance load to be determined After being applied for a preset period, the lateral surface disturbance load is removed. Apply tangential disturbance load to the rock specimen At this point, the tangential disturbance load applied to the rock specimen is: The total tangential load on the rock specimen is ;

[0026] S7, Disturbance load at the tangential point After being applied for a preset period, the tangential disturbance load is removed. Tangential point disturbance load After the static load drops to 0, the tangential static load is removed. When the tangential static load drops to a fixed value, the normal static load and the lateral static load are removed in sequence. The test ends when the tangential static load, normal static load and lateral static load all drop to 0.

[0027] As a further description of the above technical solution: the normal surface disturbance load mentioned in step S4 The amplitude is Size is The lateral surface disturbance load described in step S5 The amplitude is Size is The tangential disturbance load described in step S6 The amplitude is Size is ,in A wave function representing a frequency of w, including trigonometric functions, sawtooth wave functions, etc.

[0028] As a further description of the above technical solution: the fixed value mentioned in step S7 approaches 0.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention is the first to realize multi-directional disturbance shear test of rock mass structural surfaces under true triaxial stress conditions. It also has the ability to combine static and dynamic loading in the normal, lateral, and tangential directions, filling the gap in existing equipment that cannot simulate the dynamic and static combined loads of real engineering projects. It enables independent application and measurement of static and dynamic loads on the same side and coaxially of the rock structural surface. In the tangential direction, it further realizes the application of disturbance loads under high and low frequency disturbance shear and static loads on opposite sides and opposite sides and opposite axes. The load application mode is flexible (point / surface loading, high and low frequency disturbances), and the entire process is accurately measured through static / dynamic force sensors and displacement sensors. It provides standardized hardware and experimental methods for the study of multi-directional disturbance shear characteristics of rock mass structural surfaces under true triaxial stress conditions. The test results can directly provide theoretical basis for engineering practices such as seismic design of underground engineering, stability analysis of blasting excavation, and slope reinforcement, and promote the deep integration of basic research and engineering application in the field of geotechnical engineering. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural schematic diagram of the true triaxial static and dynamic multi-directional multi-mode combined loading and shearing device of the present invention.

[0032] Figure 2 This is a longitudinal sectional view of the true triaxial static-dynamic multi-directional multi-mode combined loading and shearing device of the present invention.

[0033] Figure 3 This is a transverse sectional view of the true triaxial static-dynamic multi-directional multi-mode combined loading and shearing device of the present invention.

[0034] Figure 4 This is a schematic diagram of the true triaxial shear box structure of the true triaxial static and dynamic multi-directional multi-mode combined loading shearing device of the present invention.

[0035] Figure 5 The stress versus time curves in each direction are shown for the true triaxial static dynamic multi-directional multi-mode combined loading shear test method of this invention during operation.

[0036] Figure 6 The graphs show the strain versus time in each direction during the operation of the true triaxial static-dynamic multi-directional multi-mode combined loading shear test method of this invention.

[0037] Figure label:

[0038] 1- Circular frame, 2- Frame base, 3- Inner frame, 4- Normal dynamic-static combined loading cylinder, 5- Tangential disturbance loading cylinder, 6- Tangential static pressure loading cylinder, 7- Lateral dynamic-static combined loading cylinder, 8- True three-way shearing box, 801- Upper pressure head, 802- Separable upper side pressure plate, 803- Cylindrical block, 804- Lower plate shearing block, 805- Separable side pressure plate II, 806- Left pressure block, 807- U-shaped plate I, 808- Right pressure block, 809- Separable side loading cylinder Pressure plate I, 810-stop block, 811-base, 812-stop bar, 813-upper plate shearing block, 814-tangential deformation measurement component, 815-lateral deformation measurement component, 816-normal deformation measurement component, 818-U-shaped plate II, 9-normal static and dynamic coaxial active loading module, 10-shear high-frequency loading module, 11-shear static low-frequency loading module, 12-lateral static and dynamic coaxial active loading module, 13-normal passive loading module, 14-lateral passive loading module. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] This embodiment provides a true triaxial static-dynamic multi-directional multi-mode combined loading shearing device, such as... Figures 1-4 As shown, it includes:

[0042] The ring frame 1 is fixed to the frame base 2 by bolts;

[0043] The inner frame 3 is bolted inside the annular frame 1, and the central axis of the inner frame 3 coincides with that of the annular frame 1.

[0044] The normal static-dynamic coaxial active loading module 9 is bolted to the middle vertical through hole of the inner frame 3 in a manner perpendicular to the horizontal plane. The normal dynamic-static combined loading cylinder 4 is fixedly installed on the top of the annular frame 1. The output end of the normal dynamic-static combined loading cylinder 4 passes through the top through hole of the annular frame 1 and is connected to the normal static-dynamic coaxial active loading module 9. The normal static-dynamic coaxial active loading module 9 and the normal dynamic-static combined loading cylinder 4 are arranged opposite each other. The normal static-dynamic coaxial active loading module 9 includes a normal static pressure cylinder, a normal static pressure piston, a normal static force sensor, a normal static pressure displacement sensor, a normal disturbance cylinder, a normal disturbance piston, a normal disturbance cylinder, a normal disturbance force sensor, a normal disturbance displacement sensor, and a normal upward pressure head, which is used to apply static low-frequency normal loads and high-frequency disturbance normal loads.

[0045] The high-frequency shear loading module 10 is fixed inside the annular frame 1 via a connecting flange. A tangential disturbance loading cylinder 5 is fixedly installed on the right side of the annular frame 1. The output end of the tangential disturbance loading cylinder 5 passes through the right side through hole of the annular frame 1 and is connected to the high-frequency shear loading module 10. The high-frequency shear loading module 10 and the tangential disturbance loading cylinder 5 are arranged opposite each other. The high-frequency shear loading module 10 includes a tangential disturbance cylinder, a tangential disturbance piston, a tangential disturbance rod, a tangential disturbance force sensor, and a tangential right pressure head, which are used to apply high-frequency disturbance shear load.

[0046] The shear static low-frequency loading module 11 is fixed inside the annular frame 1 by a connecting flange and is positioned opposite to the shear high-frequency loading module 10. A tangential static pressure loading cylinder 6 is fixedly installed on the left side of the annular frame 1. The output end of the tangential static pressure loading cylinder 6 passes through the left through hole of the annular frame 1 and is connected to the shear static low-frequency loading module 11. The tangential static pressure loading cylinder 6 is positioned opposite to the shear static low-frequency loading module 11. The shear static low-frequency loading module 11 includes a tangential static pressure cylinder, a tangential static pressure piston, a tangential static force sensor, a tangential static pressure displacement sensor, and a tangential left pressure head, and is used to apply static low-frequency shear load.

[0047] A lateral static-dynamic coaxial active loading module 12 is fixed inside the inner frame 3. A lateral dynamic-static combined loading cylinder 7 is fixedly installed on the front side of the inner frame 3. The output end of the lateral dynamic-static combined loading cylinder 7 passes through the through hole on the front side of the inner frame 3 and is connected to the lateral static-dynamic coaxial active loading module 12. The lateral static-dynamic coaxial active loading module 12 and the lateral dynamic-static combined loading cylinder 7 are arranged opposite each other. The lateral static-dynamic coaxial active loading module 12 includes a lateral static pressure cylinder, a lateral static pressure piston, a lateral static force sensor, a lateral static pressure displacement sensor, a lateral disturbance cylinder, a lateral disturbance piston, a lateral disturbance rod, a lateral disturbance force sensor, a lateral disturbance displacement sensor, and a lateral forward pressure head, which is used to apply high-frequency disturbance lateral load.

[0048] The normal passive loading module 13 is fixed to the lower side of the inner frame 3 in a manner perpendicular to the horizontal plane, and is set opposite to the normal static and dynamic coaxial active loading module 9. The normal passive loading module 13 includes a fixed frame and a normal downward pressure head, which is used to provide normal load reaction force.

[0049] The lateral passive loading module 14 is fixedly installed on the rear side of the inner frame 3 and is positioned opposite the lateral static and dynamic coaxial active loading module 12. The lateral passive loading module 14 includes a lateral horizontal support platform and a lateral rear pressure head, which are used to provide lateral load reaction force.

[0050] A true triaxial shear box 8 is placed on the fixed frame of the normal passive loading module 13, and has a specimen mounting cavity inside, in which a rock specimen is placed. The true triaxial shear box 8 includes an upper pressure head 801, a separate upper side pressure plate 802, a cylindrical block 803, a lower plate shear block 804, a separate side pressure plate II 805, a left pressure block 806, a U-shaped plate I 807, a right pressure block 808, a separate side pressure plate I 809, a stop block 810, a base 811, a stop strip 812, an upper plate shear block 813, a tangential deformation measurement component 814, a lateral deformation measurement component 815, a normal deformation measurement component 816, and a U-shaped plate II 818. The lower plate shear block 804, the upper plate shear block 813, the separate side pressure plate I 809, and the separate side pressure plate II... 805 are alternately arranged on the base 811, with the upper shear block 813 and the lower shear block 804 facing each other. Separate lateral pressure plate I 809 and separate lateral pressure plate II 805 are also facing each other, forming a specimen mounting cavity for placing the rock specimen. The cylindrical block 803 is fitted to the stop block 810 through the opening at the lower shear block 804, and the stop block 810 is fitted to the rock specimen through the cylindrical block 803. A stop strip 812 is placed between the rock specimen and the upper shear block 813. The separate upper pressure plate 802 is placed on the upper surface of the rock specimen, and the upper pressure head 801 is placed on the upper surface of the separate upper pressure plate 802. The left pressure block 806 is placed on the left side surface of the separate lateral pressure plate I 809, and the right pressure block 808 is placed on the right side of the separate lateral pressure plate II 805 in the same manner. The U-shaped plate I 807 is fixed to the separate lateral pressure plate I with bolts. On the left side of 809, U-shaped plate II 818 is also fixed to the right side of the split lateral pressure plate II 805 by bolts. Normal deformation measurement component 816 passes through the upper plate shear block and is fixed between the mounting head 801 and the base 811. Tangential deformation measurement component 814 is fixedly installed between the lower plate shear block 804 and the upper plate shear block 813. Lateral deformation measurement component 815 passes through the upper plate shear block and is fixedly installed between the split lateral pressure plate I 809 and the split lateral pressure plate II 805.

[0051] Among them, the core components that directly contact the rock specimen and transfer the load, or need to withstand complex environments such as high temperature, high pressure, and corrosion, are all made of Hastelloy alloy. Specifically, these include: the upper pressure head 801, the separate upper side pressure plate 802, the lower shear block 804, the upper shear block 813, the separate side pressure plate I 809, the separate side pressure plate II 805, the left pressure block 806, and the right pressure block 808 in the true triaxial shear box 8 which directly contact the rock specimen and transfer the load; and the pressure head components in each loading module that directly contact the shear box or load transfer components, such as the normal upward pressure head of the normal static-dynamic coaxial active loading module 9, the tangential right pressure head of the shear high frequency loading module 10, the tangential left pressure head of the shear static low frequency loading module 11, the lateral forward pressure head of the lateral static-dynamic coaxial active loading module 12, the normal downward pressure head of the normal passive loading module 13, and the lateral rearward pressure head of the lateral passive loading module 14. These components need to directly transmit triaxial static and dynamic loads and may come into contact with fluids, high-temperature media or corrosive substances in multi-factor coupled tests (such as seepage, high temperature, chemical corrosion). The corrosion resistance, high temperature resistance and high water pressure erosion resistance of Hastelloy can ensure its structural stability and load transmission accuracy, avoid component wear affecting test results, and support the device to adapt to more complex engineering scenario simulations.

[0052] Example 2

[0053] This embodiment provides a true triaxial static-dynamic multi-directional multi-mode combined loading shear test method, using the apparatus of Embodiment 1, and includes the following steps:

[0054] S1: The rock specimen is loaded into the specimen mounting cavity of the true triaxial shear box 8, and then the true triaxial shear box 8 is placed on the fixed frame of the normal passive loading module 13 and fixed with a pressure head, so that the central axis of the normal static and dynamic coaxial active loading module 9 and the normal passive loading module 13 coincides with the normal center line of the rock specimen, realizing independent loading and independent measurement of the same side and coaxiality in the normal direction; the central axis of the shear static low-frequency loading module 11 and the shear high-frequency loading module 10 coincides with the tangential center line of the rock specimen, realizing independent loading and independent measurement of opposite sides and opposite axes in the tangential direction; at the same time, the central axis of the lateral static and dynamic coaxial active loading module 12 and the lateral passive loading module 14 coincides with the lateral center line of the rock specimen, realizing independent loading and independent measurement of the same side and coaxiality in the lateral direction;

[0055] S2: Start the static oil source and first implement displacement control on the normal dynamic-static combined loading cylinder 4, so that the normal static-dynamic coaxial active loading module 9 provides normal load acting on the top surface of the true triaxial shear box 8, while the normal passive loading module 13 provides normal load reaction force acting on the bottom surface of the true triaxial shear box 8, thereby applying normal preload to the rock specimen. Next, displacement control is applied to the lateral dynamic-static combined loading cylinder 7, causing the lateral static-dynamic coaxial active loading module 12 to provide lateral loads acting on the front side of the true triaxial shear box 8, while the lateral passive loading module 14 provides lateral load reaction forces acting on the rear side of the true triaxial shear box 8, thereby applying lateral preload to the rock specimen. Then, displacement control is applied to the tangential static pressure loading cylinder 6, so that the shear static low-frequency loading module 11 provides tangential load acting on the left side of the true triaxial shear box 8, while the shear high-frequency loading module 10 provides tangential load reaction force acting on the right side of the true triaxial shear box 8, thereby applying tangential preload to the rock specimen. ;

[0056] S3: By simultaneously controlling the normal dynamic-static combined loading cylinder 4 and the lateral dynamic-static combined loading cylinder 7 using the stress control method, the normal static-dynamic coaxial active loading module 9 and the lateral static-dynamic coaxial active loading module 12 respectively apply normal static loads to the rock specimen. and lateral static load The normal static load applied to the opposite side of the rock specimen by the normal passive loading module 13 and the lateral passive loading module 14 is also... Lateral static load is also ,like Figure 5 The stress curves in the normal direction and the lateral direction are shown below;

[0057] At this time, the normal static load on the rock specimen The size is:

[0058] ;

[0059] Lateral static load The size is:

[0060] ;

[0061] Normal static load to be applied and lateral static load After stabilization, the tangential static load cylinder 6 is controlled by the stress control method to apply a tangential static load to the rock specimen by the shear static low-frequency loading module 11. The tangential static load applied to the opposite side of the rock specimen by the shear high-frequency loading module 10 is also... ,like Figure 5 The tangential stress curve is shown below:

[0062] At this time, the rock specimen is subjected to a tangential static load. The size is:

[0063] ;

[0064] S4: Tangential stress After stabilization, the dynamic oil source is activated, and a preset normal surface disturbance load is applied to the dynamic-static combined loading cylinder 4 through force control. This allows the normal disturbance force sensor of the normal static-dynamic coaxial active loading module 9 to display the normal surface disturbance load. Since the normal disturbance rod and the normal active end are on the same side and coaxial, the total normal load on the rock specimen is... For the normal static load With the normal surface disturbance load sum;

[0065] The amplitude of the normal surface disturbance load is After the disturbance begins, the applied normal surface disturbance load The size is:

[0066] =2MPa,

[0067] in A wave function representing a frequency of w, including trigonometric functions, sawtooth wave functions, etc.

[0068] At this point, the normal surface disturbance load on the rock specimen The size is:

[0069] ;

[0070] Normal static load The magnitude is the same as before the disturbance began, still being:

[0071] ;

[0072] Therefore, the total normal load on the rock specimen The size is:

[0073] =32MPa;

[0074] The normal strain of the test specimen was monitored using the normal deformation measurement component 816. The strain exhibited periodic fluctuations with the disturbance load, eventually approaching 0.11% during the stable disturbance phase (e.g., ...). Figure 6 (As shown in the mid-normal strain curve).

[0075] S5: Disturbance load on the normal surface After being applied for a preset number of cycles T, the normal surface disturbance load is removed. The preset lateral surface disturbance load is applied by the force-controlled lateral dynamic-static combined loading cylinder 7. This causes the lateral disturbance force sensor on the lateral static-dynamic coaxial active loading module 12 to display the lateral surface disturbance load as... Since the lateral disturbance rod and the lateral active end are on the same side and coaxial, the total lateral load on the rock specimen is... The lateral static load With the lateral surface disturbance load sum;

[0076] Lateral surface disturbance load amplitude is After the disturbance begins, the applied lateral surface disturbance load The size is:

[0077] ;

[0078] At this point, the rock specimen is subjected to lateral surface disturbance loads. The size is:

[0079] ;

[0080] Lateral static load The magnitude is the same as before the disturbance began, still being:

[0081] ;

[0082] Therefore, the total lateral load on the rock specimen The size is:

[0083] =27MPa;

[0084] Lateral strain of the test specimen was monitored using the lateral deformation measurement component 815. The strain fluctuated periodically with the disturbance load, and after stabilization, it tended to approach 0.05% (e.g., Figure 6 The lateral strain curve (as shown in the curve) is significantly smaller than the normal strain, demonstrating the inhibitory effect of lateral constraint on the transverse deformation of the specimen.

[0085] S6: Lateral surface disturbance load to be determined After being applied for a preset number of cycles T, the lateral surface disturbance load is removed. The preset tangential point disturbance load is applied by the force-controlled tangential hydrostatic loading cylinder 6. This causes the tangential disturbance force sensor on the high-frequency shear loading module 10 to display the tangential point disturbance load as... Because the tangential disturbance rod and the tangential active end act simultaneously on opposite sides and along different axes, the total tangential load on the rock specimen is... For the tangential static load With the tangential disturbance load difference;

[0086] The amplitude of the tangential disturbance load is After the disturbance begins, the applied tangential disturbance load The size is:

[0087] ;

[0088] At this point, the tangential disturbance load on the rock specimen The size is:

[0089] ;

[0090] Tangential static load The magnitude is the same as before the disturbance began, still being:

[0091] ;

[0092] Therefore, the total tangential load on the rock specimen The size is:

[0093] ;

[0094] The tangential strain of the test specimen was monitored using the tangential deformation measurement component 814. Since the tangential direction is the primary shear direction, the strain fluctuation was the largest, reaching 0.32% after stabilization (e.g., ...). Figure 6 The tangential strain curve (shown in the figure) reflects the dominant shear deformation characteristics of the rock specimen along the structural plane; at the same time, the initiation and propagation of cracks inside the specimen can be analyzed by combining acoustic emission signals.

[0095] S7: Disturbance load at the tangential point After being applied for a preset number of cycles T, the tangential disturbance load is removed. Tangential point disturbance load When the static load drops to 0, the tangential static load is removed. Once the tangential static load drops to a fixed value, the normal static load and the lateral static load are removed in sequence. The test ends when the tangential static load, normal static load, and lateral static load all drop to 0.

[0096] It should be noted that the fixed value mentioned is close to 0, and can be set according to the actual situation.

[0097] Figure 6 The curves showing the changes of normal strain (stable value 0.11%), lateral strain (stable value 0.05%) and shear strain (stable value 0.32%) over time during the test are presented, reflecting the deformation response of the rock specimen under load.

[0098] The experimental method of this invention first applies normal, lateral, and tangential preload to eliminate the gap between the rock specimen and the true triaxial shear box. Then, it applies normal, lateral, and tangential static loads in stress-controlled mode to restore the steady-state stress field of the underground rock mass. Subsequently, it applies normal / lateral surface disturbances and tangential point disturbances in the order of normal, lateral, and tangential to simulate blasting and seismic effects. Finally, it achieves multi-dimensional effects: on the one hand, the stepped loading and independent measurement system ensures data accuracy and successfully obtains stable stress-strain-time response data. The synchronously acquired acoustic emission signals also clearly track the crack initiation and propagation process inside the rock mass. This experiment intuitively reveals the mechanical law that the tangential direction is the main shear deformation direction and lateral constraints can significantly suppress transverse deformation. On the other hand, based on the corrosion and high temperature resistance of Hastelloy components, this experimental procedure can be directly connected to seepage and high temperature devices to expand multi-factor coupled tests. Moreover, the obtained parameters such as peak shear strength, shear stiffness, and disturbance sensitivity coefficient of rock mass can provide quantitative basis for tunnel seismic design and mine blasting parameter optimization. It completely solves the problem of result deviation caused by the simplification of stress environment in traditional direct shear tests, and provides experimental support with both scientific and engineering value for the study of rock mass structural surface shear characteristics under true triaxial dynamic and static combined loads.

[0099] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A true triaxial static-dynamic multi-directional multi-mode combined loading shearing device, comprising an annular frame (1) and an inner frame (3), wherein the inner frame (3) is fixed within the annular frame (1); characterized in that, Also includes: The normal static and dynamic coaxial active loading module (9) is fixed in the middle vertical through hole of the inner frame (3) and connected to the normal dynamic and static combined loading cylinder (4) fixed in the upper through hole of the ring frame (1) for applying static low-frequency normal load and high-frequency disturbance normal load. The high-frequency shear loading module (10) is connected to the tangential disturbance loading cylinder (5) fixed in the through hole on one side of the ring frame (1) and is used to apply high-frequency disturbance shear load. The shearing static low-frequency loading module (11) is connected to the tangential static pressure loading cylinder (6) fixed in the through hole on the other side of the ring frame (1) and is used to apply static low-frequency shear load. The lateral static and dynamic coaxial active loading module (12) is connected to the lateral dynamic and static combined loading cylinder (7) fixed in the through hole on one side of the inner frame (3) and is used to apply high-frequency disturbance lateral load. The normal passive loading module (13) is fixed to the lower side of the inner frame (3) and is set opposite to the normal static and dynamic coaxial active loading module (9) to provide normal load reaction force; The lateral passive loading module (14) is fixed on the other side of the inner frame (3) and is set opposite to the lateral static and dynamic coaxial active loading module (12) to provide lateral load reaction force; The true triaxial shear box (8) is placed on the normal passive loading module (13). The true triaxial shear box (8) has a specimen mounting cavity inside, which is used to accommodate the rock specimen and realize triaxial loading. The true three-dimensional shear box (8) includes an upper pressure head (801), a separate upper side pressure plate (802), a cylindrical block (803), a lower plate shearing block (804), a separate side pressure plate II (805), a left pressure block (806), a U-shaped plate I (807), a right pressure block (808), a separate side pressure plate I (809), a stop block (810), a base (811), a stop bar (812), an upper plate shearing block (813), a tangential deformation measurement component (814), a lateral deformation measurement component (815), and a normal deformation measurement component (816). 6) and U-shaped plate II (818), the lower plate shear block (804), the upper plate shear block (813), the separate lateral pressure plate I (809) and the separate lateral pressure plate II (805) are alternately arranged on the base (811), and the upper plate shear block (813) and the lower plate shear block (804) are arranged opposite each other, and the separate lateral pressure plate I (809) and the separate lateral pressure plate II (805) are arranged opposite each other to form a specimen installation cavity for placing rock specimens; the cylindrical block (803) passes through the hole at the lower plate shear block (804) and the stop block (8 10) Fitting: The stop block (810) is fitted to the rock specimen via the cylindrical block (803). The stop strip (812) is placed between the rock specimen and the upper shear block (813). The split upper pressure plate (802) is placed on the upper surface of the rock specimen. The upper pressure head (801) is placed on the upper surface of the split upper pressure plate (802). The left pressure block (806) is placed on the left side surface of the split lateral pressure plate I (809). The right pressure block (808) is placed on the right side of the split lateral pressure plate II (805) in the same manner. The U-shaped plate I (807) is fixed to the split lateral pressure plate II. On the left side of pressure plate I (809), U-shaped plate II (818) is fixed to the right side of split lateral pressure plate II (805). Normal deformation measurement component (816) passes through the upper plate shear block and is fixed between the mounting head (801) and the base (811). Tangential deformation measurement component (814) is fixedly installed between the lower plate shear block (804) and the upper plate shear block (813). Lateral deformation measurement component (815) passes through the upper plate shear block (813) and is fixedly installed between split lateral pressure plate I (809) and split lateral pressure plate II (805).

2. The true triaxial static-dynamic multi-directional multi-mode combined loading shearing device according to claim 1, characterized in that: The central axes of the inner frame (3) and the ring frame (1) coincide.

3. The true triaxial static-dynamic multi-directional multi-mode combined loading shearing device according to claim 1, characterized in that: The normal static-dynamic coaxial active loading module (9) is perpendicular to the horizontal plane and is set directly opposite to the normal dynamic-static combined loading cylinder (4).

4. The true triaxial static-dynamic multi-directional multi-mode combined loading shearing device according to claim 1, characterized in that: The shearing high-frequency loading module (10), tangential disturbance loading cylinder (5), tangential static pressure loading cylinder (6) and shearing static low-frequency loading module (11) are arranged facing each other.

5. The true triaxial static-dynamic multi-directional multi-mode combined loading shearing device according to claim 1, characterized in that: The lateral static-dynamic coaxial active loading module (12) is positioned opposite the lateral static-dynamic combined loading cylinder (7).

6. A test method for the true triaxial static-dynamic multi-directional multi-mode combined loading shearing device according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Place the rock specimen in the specimen mounting cavity of the true triaxial shear box (8) and place the true triaxial shear box (8) on the normal passive loading module (13); S2. Start the static oil source and apply normal preload to the rock specimens sequentially. Lateral preload and shear preload ; S3. Apply normal static load to the rock specimen simultaneously using the stress control method. and lateral static load Normal static load on rock specimen The size is Lateral static load The size is ; Apply tangential static load only after the normal and lateral static loads have stabilized. Tangential static load on rock specimen The size is ; S4. After the tangential static load stabilizes, start the dynamic oil source to apply a normal surface disturbance load to the rock specimen. At this time, the normal surface disturbance load on the rock specimen is The total normal load on the rock specimen is ; S5, Disturbance load on the normal surface After being applied for a preset period, the normal surface disturbance load is removed. Lateral surface disturbance loads were applied to the rock specimens. At this point, the lateral surface disturbance load on the rock specimen is The total lateral load on the rock specimen is ; S6, Lateral surface disturbance load to be determined After being applied for a preset period, the lateral surface disturbance load is removed. Apply tangential disturbance load to the rock specimen At this point, the tangential disturbance load applied to the rock specimen is: The total tangential load on the rock specimen is ; S7, Disturbance load at the tangential point After being applied for a preset period, the tangential disturbance load is removed. Tangential point disturbance load After the static load drops to 0, the tangential static load is removed. When the tangential static load drops to a fixed value, the normal static load and the lateral static load are removed in sequence. The test ends when the tangential static load, normal static load and lateral static load all drop to 0.

7. The test method according to claim 6, characterized in that: The normal surface disturbance load described in step S4 The amplitude is Size is .

8. The test method according to claim 6, characterized in that: The lateral surface disturbance load described in step S5 The amplitude is Size is .

9. The test method according to claim 6, characterized in that: The tangential disturbance load described in step S6 The amplitude is Size is .

10. The test method according to claim 6, characterized in that: The fixed value mentioned in step S7 approaches 0.

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