True triaxial static and dynamic multidirectional multimode combined loading shearing device and test method

Abstract

The invention discloses a true triaxial static and dynamic multidirectional multimode combined loading shearing 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 shearing 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 three-way shearing box, and all the loading modules are connected with corresponding oil cylinders respectively to realize three-way load application; according to the test method, normal, lateral and tangential preloads are sequentially applied, then three-way static loads are applied, and finally normal surface, lateral surface and tangential point disturbance loads are applied, so that three-way static and dynamic force independent application and measurement of the rock mass structural surface and point-surface high and low frequency dynamic and static combined load loading are realized, and a complex stress environment is simulated; and a reliable hardware and test means is provided for the research on the multi-direction disturbance shear characteristics of the rock mass structural surface under true triaxial.

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 and dynamic coaxial active loading module is perpendicular to the horizontal plane and is arranged opposite to the normal dynamic and static combined loading oil cylinder.

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

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

[0018] The second technical solution adopted by the present application provides a test method based on the above-mentioned true triaxial static and dynamic force multi-directional and multi-mode combined loading shear device, which comprises the following steps:

[0019] S1, placing the rock test piece in the test piece mounting cavity of the true triaxial shear box, and placing the true triaxial shear box on the normal passive loading module;

[0020] S2, starting the static oil source, and sequentially applying a normal pre-load , a lateral pre-load and a shear pre-load to the rock test piece;

[0021] S3, simultaneously applying a normal static load and a lateral static load to the rock test piece by a stress control method, wherein the size of the normal static load experienced by the rock test piece is , and the size of the lateral static load experienced by the rock test piece is ;

[0022] After the normal static load and the lateral static load are stable, a tangential static load is applied, and the size of the tangential static load experienced by the rock test piece is ;

[0023] S4, after the tangential static load is stable, a dynamic oil source is started, and a normal surface disturbance load is applied to the rock test piece, wherein the normal surface disturbance load experienced by the rock test piece is , and the total normal load experienced by the rock test piece is ;

[0024] S5, after the normal surface disturbance load is applied to a preset period, the normal surface disturbance load is removed, and a lateral surface disturbance load is applied to the rock test piece; at this time, the lateral surface disturbance load experienced by the rock test piece is , the total lateral load on the rock sample is ;

[0025] S6, the lateral surface disturbance load is applied to the rock sample , the tangential point disturbance load is applied to the rock sample ; at this time, the tangential point disturbance load on the rock sample is , the total tangential load on the rock sample is ;

[0026] S7, the tangential point disturbance load is applied to the rock sample , the tangential point disturbance load is reduced to 0, the tangential static load is unloaded, and then the normal static load and the lateral static load are unloaded in turn when the tangential static load is reduced to a fixed value, and the test is ended when the tangential static load, the normal static load and the lateral static load are all reduced to 0.

[0027] As a further description of the above technical solution: the amplitude of the normal surface disturbance load in step S4 is , and the size is ; the amplitude of the lateral surface disturbance load in step S5 is , and the size is ; the amplitude of the tangential point disturbance load in step S6 is , and the size is , wherein represents a wave function with a frequency of w, including a triangular function, a sawtooth wave function, etc.

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

[0029] Compared with the prior art, the beneficial effects of the present application are:

[0030] The present application realizes the multi-direction disturbance shear test of the rock mass structure surface under the true triaxial stress condition for the first time, has the static and dynamic combined loading capacity in three directions of normal direction, lateral direction and tangential direction, fills the blank that the existing equipment cannot simulate the real engineering static and dynamic combined load, realizes the independent application and independent measurement of the static and dynamic force of the rock structure surface on the same side and same shaft, realizes the disturbance load application under the high and low frequency disturbance shear of the different sides and same shaft and the disturbance load application under the static load of the different sides and different shafts, realizes the flexible load application mode (point / surface loading, high and low frequency disturbance), and realizes the accurate measurement through the static / dynamic force sensor and displacement sensor; the present application provides the standardized hardware and test method for the multi-direction disturbance shear characteristic research of the rock mass structure surface under the true triaxial stress condition, and the test result can directly provide the theoretical basis for the underground engineering anti-seismic design, the stability analysis of blasting excavation, slope reinforcement and other engineering practices, and promotes the deep integration of the basic research and engineering application in the field of geotechnical engineering. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a three-dimensional schematic view of the structure of the static and dynamic multi-direction multi-mode combined loading shear device under the true triaxial.

[0032] Figure 2 It is a longitudinal sectional view of the static and dynamic multi-direction multi-mode combined loading shear device under the true triaxial.

[0033] Figure 3 It is a transverse sectional view of the static and dynamic multi-direction multi-mode combined loading shear device under the true triaxial.

[0034] Figure 4 It is a true triaxial shear box structure schematic view of the static and dynamic multi-direction multi-mode combined loading shear device under the true triaxial.

[0035] Figure 5 It is a stress-time fold line graph of each direction when the static and dynamic multi-direction multi-mode combined loading shear test method under the true triaxial is running.

[0036] Figure 6 It is a strain-time fold line graph of each direction when the static and dynamic multi-direction multi-mode combined loading shear test method under the true triaxial is running.

[0037] Reference signs:

[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 shear high-frequency loading module 10 is fixed in the annular frame 1 through the connecting flange, and the tangential disturbance loading oil cylinder 5 is fixedly installed on the right side of the annular frame 1, the output end of the tangential disturbance loading oil cylinder 5 penetrates through the right side through hole of the annular frame 1 and is connected with the shear high-frequency loading module 10, the shear high-frequency loading module 10 is arranged opposite to the tangential disturbance loading oil cylinder 5, and the shear high-frequency loading module 10 comprises a tangential disturbance cylinder, a tangential disturbance piston, a tangential disturbance rod, a tangential disturbance force sensor and a tangential right pressure head, and is used for applying a high-frequency disturbance shear load;

[0046] The shear static low-frequency loading module 11 is fixed in the annular frame 1 through the connecting flange and is arranged opposite to the shear high-frequency loading module 10, the tangential static pressure loading oil cylinder 6 is fixedly installed on the left side of the annular frame 1, the output end of the tangential static pressure loading oil cylinder 6 penetrates through the left side through hole of the annular frame 1 and is connected with the shear static low-frequency loading module 11, the tangential static pressure loading oil cylinder 6 is arranged opposite to the shear static low-frequency loading module 11, and the shear static low-frequency loading module 11 comprises a tangential static pressure cylinder, a tangential static pressure piston, a tangential static force sensor, a tangential static displacement sensor and a tangential left pressure head, and is used for applying a static low-frequency shear load;

[0047] The lateral static-dynamic coaxial active loading module 12 is fixed in the inner frame 3, the lateral dynamic-static combined loading oil cylinder 7 is fixedly installed on the front side of the inner frame 3, the output end of the lateral dynamic-static combined loading oil cylinder 7 penetrates through the front side through hole of the inner frame 3 and is connected with the lateral static-dynamic coaxial active loading module 12, the lateral static-dynamic coaxial active loading module 12 is arranged opposite to the lateral dynamic-static combined loading oil cylinder 7, and the lateral static-dynamic coaxial active loading module 12 comprises a lateral static pressure cylinder, a lateral static pressure piston, a lateral static force sensor, a lateral static displacement sensor, a lateral disturbance cylinder, a lateral disturbance piston, a lateral disturbance dry rod, a lateral disturbance force sensor, a lateral disturbance displacement sensor and a lateral front pressure head, and is used for applying a 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 arranged opposite to the normal static-dynamic coaxial active loading module 9, the normal passive loading module 13 comprises a fixed frame and a normal lower pressure head, and is used for providing a 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 arranged opposite to the lateral static-dynamic coaxial active loading module 12, and the lateral passive loading module 14 comprises a lateral horizontal support platform and a lateral rear pressure head and is used for providing a 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] The core components directly contacting the rock sample and transmitting the load or needing to withstand complex environments such as high temperature, high pressure, corrosion, etc. are made of hastelloy material, including: the upper pressure head 801 directly contacting the rock sample and transmitting the load in the true triaxial shear box 8, the split upper side pressure plate 802, the lower disc shear block 804, the upper disc shear block 813, the split side pressure plate I 809, the split side pressure plate II 805, the left pressure block 806, and the right pressure block 808; the pressure head components directly contacting the shear box or load transmission components in each loading module, such as the normal upper pressure head of the normal static and 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 front pressure head of the lateral static and dynamic coaxial active loading module 12, and the normal lower pressure head of the normal passive loading module 13, and the lateral rear pressure head of the lateral passive loading module 14. These components need to directly transmit three-way static and dynamic force loads, and may contact fluids, high-temperature media or corrosive substances in multi-factor coupling tests (such as seepage, high temperature, chemical corrosion). The corrosion resistance, high temperature resistance, and high water pressure scouring resistance of hastelloy can ensure the structural stability and load transmission accuracy, avoid component wear affecting the test results, and support the device to adapt to more complex engineering scene simulation.

[0052] Embodiment two

[0053] The embodiment provides a true triaxial static and dynamic force multi-directional and multi-mode combined loading shear test method, which adopts the device of embodiment one, and includes the following steps:

[0054] S1: The rock sample is loaded into the sample mounting cavity of the true triaxial shear box 8, then the true triaxial shear box 8 is placed on the fixed frame of the normal passive loading module 13, and is fixed by the pressure head, so that the central axes of the normal static and dynamic coaxial active loading module 9 and the normal passive loading module 13 are coincided with the normal central line of the rock sample, realizing normal same-side coaxial independent loading and independent measurement; the central axes of the shear static low-frequency loading module 11 and the shear high-frequency loading module 10 are coincided with the tangential central line of the rock sample, realizing tangential different-side coaxial independent loading and independent measurement; at the same time, the central axes of the lateral static and dynamic coaxial active loading module 12 and the lateral passive loading module 14 are coincided with the lateral central line of the rock sample, realizing lateral same-side coaxial independent loading and independent measurement.

[0055] S2: The static oil source is started, displacement control is first performed on the normal dynamic and static combined loading oil cylinder 4, so that the normal static and dynamic coaxial active loading module 9 provides a normal load acting on the top surface of the true triaxial shear box 8, and the normal passive loading module 13 provides a normal load reaction acting on the bottom surface of the true triaxial shear box 8, thereby applying a normal pre-load to the rock sample ; then the lateral dynamic-static combined loading oil cylinder 7 is controlled to displace, so that the lateral dynamic-static coaxial active loading module 12 provides lateral load to the front side of the true three-dimensional shear box 8, and the lateral passive loading module 14 provides the lateral load counterforce to the back side of the true three-dimensional shear box 8, thereby applying lateral pre-load to the rock sample ; then the tangential static pressure loading oil cylinder 6 is controlled to displace, so that the shear static low-frequency loading module 11 provides tangential load to the left side of the true three-dimensional shear box 8, and the shear high-frequency loading module 10 provides the tangential load counterforce to the right side of the true three-dimensional shear box 8, thereby applying tangential pre-load to the rock sample ;

[0056] S3: the normal dynamic-static combined loading oil cylinder 4 and the lateral dynamic-static combined loading oil cylinder 7 are controlled by the stress control method, so that the normal dynamic-static coaxial active loading module 9 and the lateral dynamic-static coaxial active loading module 12 respectively apply normal static load and lateral static load to the rock sample , and the relative side of the rock sample applies normal static load and lateral static load to the other side of the rock sample through the normal passive loading module 13 and the lateral passive loading module 14 , and the relative side of the rock sample applies normal static load and lateral static load to the other side of the rock sample through the normal passive loading module 13 and the lateral passive loading module 14 , as shown in the normal stress curve and the lateral stress curve in Figure 5 ;

[0057] The normal static load experienced by the rock sample at this time is:

[0058] ;

[0059] The lateral static load experienced by the rock sample at this time is:

[0060] ;

[0061] After the normal static load and the lateral static load to be applied are stabilized, the tangential static pressure loading oil cylinder 6 is controlled by the stress control method, so that the shear static low-frequency loading module 11 applies tangential static load to the rock sample , and the relative side of the rock sample applies tangential static load to the other side of the rock sample through the shear high-frequency loading module 10 , as shown in the tangential stress curve in Figure 5 ;

[0062] The tangential static load experienced by the rock sample at this time is:

[0063] ; ​

[0064] S4: the tangential stress to be cut After stabilization, start the dynamic oil source, and apply a preset normal surface disturbance load to the oil cylinder 4 through the force control method of normal static and dynamic combined loading Make the normal disturbance load of the normal static and dynamic coaxial active loading module 9 be displayed by the normal disturbance load cell Because the normal disturbance rod and the normal active end are coaxial on the same side, the total normal load on the rock sample is The normal static load and the normal surface disturbance load ;

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

[0066] = 2 MPa

[0067] Wherein represents a wave function with a frequency of w, including a triangular function, a sawtooth wave function, etc.

[0068] At this time, the size of the normal surface disturbance load on the rock sample :

[0069] ;

[0070] The size of the normal static load is consistent before the disturbance starts, which is still

[0071] ;

[0072] Therefore, the size of the total normal load on the rock sample :

[0073] = 32 MPa

[0074] The normal strain of the sample is monitored through the normal deformation measurement assembly 816, at this time the strain presents periodic fluctuations with the disturbance load, and finally tends to 0.11% in the disturbance stabilization stage (as shown in the normal strain curve in Figure 6 );

[0075] S5: the normal surface disturbance load to be applied After a preset number of periods T, the normal surface disturbance load is removed ; a preset lateral surface disturbance load is applied to the oil cylinder 7 through the force control lateral static and dynamic combined loading , so that the lateral disturbance load cell on the lateral static and dynamic coaxial active loading module 12 displays 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 of the tangential point disturbance load is:

[0087] ;

[0088] At this time, the tangential point disturbance load exerted on the rock sample is:

[0089] ;

[0090] The size of the tangential static load exerted on the rock sample is consistent with that before the disturbance, and is still:

[0091] ;

[0092] Therefore, the size of the total tangential load exerted on the rock sample is:

[0093] ;

[0094] The tangential strain of the sample is monitored through the tangential deformation measuring assembly 814. Since the tangential direction is the main shear direction, the strain fluctuation amplitude is the largest, and after stabilization, it reaches 0.32% (as shown in the tangential strain curve in FIG. 8), which reflects the dominant characteristics of the shear deformation of the rock sample along the structural plane. At the same time, in combination with the acoustic emission signal, the initiation and expansion law of the internal cracks of the sample can be analyzed. Figure 6

[0095] S7: After the tangential point disturbance load is applied to the rock sample for a preset period T, the tangential point disturbance load is unloaded, and when the tangential point disturbance load is reduced to 0, the tangential static load is unloaded, and when the tangential static load is reduced to a fixed value, the normal static load and the lateral static load are unloaded in turn, and when the tangential static load, the normal static load, and the lateral static load are all reduced to 0, the test is ended. It should be noted that the fixed value tends to 0, and can be set according to the actual situation.

[0096]

[0097] Figure 6 The normal strain (stable value 0.11%), lateral strain (stable value 0.05%), and shear strain (stable value 0.32%) change curves with time during the test are shown, which reflect the deformation response of the rock sample under the action of the load.

[0098] ​​​​The test method of the application eliminates the gap between the rock test piece and the true triaxial shear box by applying normal, lateral and tangential pre-pressing first, then applies static load of normal, lateral and tangential directions in stress control mode to restore the steady stress field of underground rock mass, then applies normal / lateral surface disturbance and tangential point disturbance of amplitude in the order of normal, lateral and tangential directions to simulate the effects of blasting and earthquake, and finally realizes multi-dimensional effect: on the one hand, the stepwise loading and independent measurement system ensures the accuracy of data, successfully obtains stable stress-strain-time response data, and the simultaneously collected acoustic emission signals also clearly track the crack initiation and propagation process in the rock mass, directly revealing the mechanical law that the tangential direction is the main shear deformation direction and the lateral constraint can significantly inhibit the lateral deformation; on the other hand, based on the corrosion and high temperature resistance of Hastelloy parts, the test process can be directly connected to the seepage and high temperature device to expand multi-factor coupling test, and the obtained parameters such as rock mass peak shear strength, shear stiffness and disturbance sensitivity coefficient can provide quantitative basis for tunnel seismic design and mine blasting parameter optimization, and completely solve the result deviation problem of traditional direct shear test caused by simplified stress environment, and provide test support with scientificity and engineering value for rock mass structure surface shear property research under true triaxial dynamic and static combined load.

[0099] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and inventive concept of the application within the technical range disclosed by the application, which should be covered in the protection scope of the application.

Claims

1. A true triaxial static-dynamic multi-directional multi-mode combined loading shear device, comprising a ring-shaped frame (1) and an inner frame (3), the inner frame (3) being fixed in the ring-shaped frame (1); characterized in that, Also include: Normal static and dynamic coaxial active loading module (9) is fixed in the middle vertical hole of inner frame (3), connected with normal dynamic and static combined loading oil cylinder (4) fixed in the upper hole of ring frame (1), used for applying static low frequency normal load and high frequency disturbance normal load; Shear high frequency loading module (10) is connected with tangential disturbance loading oil cylinder (5) fixed in the hole of one side of ring frame (1), used for applying high frequency disturbance shear load; Shear static low frequency loading module (11) is connected with tangential static pressure loading oil cylinder (6) fixed in the hole of the other side of ring frame (1), used for applying static low frequency shear load; Lateral static and dynamic coaxial active loading module (12) is connected with lateral dynamic and static combined loading oil cylinder (7) fixed in the hole of one side of inner frame (3), used for applying high frequency disturbance lateral load; Normal passive loading module (13) is fixed on the lower side of inner frame (3) and is opposite to normal static and dynamic coaxial active loading module (9), used for providing normal load reaction; Lateral passive loading module (14) is fixed on the other side of inner frame (3) and is opposite to lateral static and dynamic coaxial active loading module (12), used for providing lateral load reaction; True three-dimensional shear box (8) is placed on normal passive loading module (13), and true three-dimensional shear box (8) is provided with specimen installation cavity for accommodating rock specimen and realizing three-dimensional loading, and is provided with tangential deformation measuring assembly (814), lateral deformation measuring assembly (815) and normal deformation measuring assembly (816).

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

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

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

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

6. The test method based on the true triaxial static-dynamic multi-directional multi-mode combined loading shear device according to any one of claims 1-5, characterized in that, The method comprises the following steps: S1, the rock specimen is placed in the specimen installation cavity of the true three-dimensional shear box (8), and the true three-dimensional shear box (8) is placed on the normal passive loading module (13); S2, start the static oil source, apply normal pre-load, lateral pre-load and shear pre-load to the rock sample in sequence ;​​ 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 ; After the normal static load and the lateral static load are stabilized, a tangential static load is applied , the tangential static load applied to the rock sample has a size of ; S4, after tangential static load stabilizes, start dynamic oil source, apply normal surface disturbance load to rock sample At this time, the normal surface disturbance load on the rock sample is The total normal load on the rock sample is ; S5, the normal plane disturbance load After a preset period, the normal plane disturbance load is removed , a lateral plane disturbance load is applied to the rock sample ; at this time, the lateral plane disturbance load on the rock sample is , and the total lateral load on the rock sample is ; S6, lateral face disturbance load after a preset period, the lateral face disturbance load is removed , a tangential point disturbance load is applied to the rock sample ; at this time, the tangential point disturbance load applied to the rock sample is , and the total tangential load applied to the rock sample is ; S7, tangential point disturbance load After a preset period of application, the tangential point disturbance load is removed , tangential point disturbance load After the tangential static load is reduced to a fixed value, the normal static load and the lateral static load are sequentially removed, and when the tangential static load, the normal static load and the lateral static load are all reduced to 0, the test is ended.

7. The test method of claim 6, wherein: The normal surface disturbing load described in step S4 with an amplitude of and a size of .

8. The test method of claim 6, wherein: The lateral face perturbation load described in step S5 with an amplitude of and a size of .

9. The test method of claim 6, wherein: The tangential point perturbation load described in step S6 with an amplitude of and a size of .

10. The test method of claim 6, wherein: The fixed value in step S7 approaches to 0.

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