CN116202889A - Rock structural surface shear instability testing machine and shear instability testing method - Google Patents
Rock structural surface shear instability testing machine and shear instability testing method Download PDFInfo
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- CN116202889A CN116202889A CN202310219002.9A CN202310219002A CN116202889A CN 116202889 A CN116202889 A CN 116202889A CN 202310219002 A CN202310219002 A CN 202310219002A CN 116202889 A CN116202889 A CN 116202889A
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- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention provides a shear instability testing machine and a shear instability testing method for a rock structural surface, comprising the following steps: rigid frame structure, normal and tangential loading mechanisms, normal and tangential measurement systems, clamping modules, and energy storage modules. The testing machine simulates the creep loading effect of surrounding rock and the impact disturbance effect of engineering machinery by applying normal and tangential dynamic and static loads to the structural surface sample; the normal and tangential energy storage modules can accumulate elastic energy in the test loading process, and when the structural surface is subjected to shear failure, the accumulated elastic energy can be instantly released, so that the energy storage effect and rebound effect of the surrounding rock mass and the shear instability failure behavior of the structural surface are simulated. The invention realizes the bidirectional impact disturbance function of the testing machine, can simulate the influence of engineering construction disturbance on the shear instability and damage behavior of the rock mass structural surface more truly, and provides a reliable research means for researching the instability and slip characteristics of the structural surface in a laboratory.
Description
Technical Field
The invention relates to the technical field of geotechnical engineering, in particular to a shear instability tester and a shear instability testing method for a rock structural surface.
Background
The current rock structural surface shear testing machine is usually a rigid or servo control testing machine, and people tend to focus on obtaining a constant shear deformation rate and realizing a stable loading process, and neglect the significance exhibited by the unsteady sliding of the rock structural surface in the loading process. In fact, the destabilization and damage phenomena of the rock are shown in most natural and engineering disasters such as the cracking and fault dislocation of crust rock in the nature and rock burst induced by rock engineering disturbance. The unsteady sliding of geological faults and the structural face type rock burst often cause serious natural disasters and engineering accidents, and cause serious casualties and property loss. Therefore, the shear instability tester and the shear instability testing method for the rock structural surface are developed, the shear instability destructive behavior of the structural surface is reproduced, and the shear instability testing method has important significance for revealing the instability sliding mechanism of the rock structural surface and predicting and preventing geotechnical engineering disasters.
The invention provides a rock structural surface shear instability tester and a shear instability test method, which are used for filling the blank in the field by taking a Cook rigidity criterion and rock dynamics as theoretical basis on the basis of a traditional shear instrument, changing loading rigidity of the tester by adding an energy storage module, simulating energy storage characteristics and rebound behavior of a surrounding rock body, simulating dynamic disturbance effects in a construction process by adding normal and tangential impact disturbance modules, recording the shear instability process of the rock structural surface by adopting a high-frequency sensor in test engineering.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides the rock structural surface shear instability testing machine and the shear instability testing method, which can not only finish the conventional rock structural surface direct shear test, but also acquire the rock structural surface shear full stress-displacement curve under the constant loading rate; and the destabilization sliding behavior of the rock structural surface is reproduced by adding the energy storage module, the impact disturbance module and utilizing the shear destabilization testing method, so that test conditions are further provided for the research work.
The aim of the invention is achieved by the following measures:
the shear instability tester for the rock structural surface comprises a rigid frame structure, a clamping module, a normal loading mechanism, a tangential loading mechanism, a normal impact disturbance module, a tangential impact disturbance module, a normal energy storage module and a tangential energy storage module;
the clamping module is movably arranged on the rigid frame structure and is used for clamping the rock structural surface sample;
the normal loading mechanism is fixedly arranged at the top of the rigid frame structure and is used for applying a normal load to a rock structural surface sample, and the working end of the normal loading mechanism is connected with the clamping module;
the tangential loading mechanism is fixedly arranged on the side surface of the rigid frame structure and is used for applying tangential load to the rock structural surface clamping sample, and the working end of the tangential loading mechanism is connected with the clamping module;
the normal impact disturbance module is arranged at the position of the corresponding normal loading mechanism at the outer side of the rigid frame structure, the tangential impact disturbance module is arranged at the position of the corresponding tangential loading mechanism at the outer side of the rigid frame structure, and the normal impact disturbance module and the tangential impact disturbance module are used for applying normal impact load and tangential impact load to the rock structural surface sample and simulating impact disturbance in the construction process;
the normal and tangential loading mechanisms are matched with the normal and tangential impact disturbance modules to simulate and research disturbance induction conditions of shear instability under different stress states;
the normal energy storage module and the tangential energy storage module are respectively connected with the normal loading mechanism and the tangential loading mechanism and are used for simulating the energy storage effect and the rebound effect of the surrounding rock mass and the shear instability and damage behavior of the structural surface.
In order to further optimize the invention, the following technical scheme can be preferably selected:
preferably, the clamping module comprises an upper clamp for clamping the upper half part of the rock structural surface sample and a lower clamp for clamping the lower half part of the rock structural surface sample, the upper clamp is connected with the movable ends of the normal loading mechanism and the normal impact disturbance mechanism, the lower clamp is connected with the movable ends of the tangential loading mechanism and the tangential impact disturbance mechanism, a normal roller is rotatably arranged on the rigid frame structure corresponding to the position of the upper clamp, a tangential roller is rotatably arranged on the rigid frame structure corresponding to the position of the upper clamp, and the normal roller and the tangential roller are used for reducing friction and improving measurement accuracy; the upper fixture and the lower fixture comprise different models and correspond to rock structural surfaces with different sizes, and the research function of the structural surface scale utility can be realized.
Preferably, the normal loading mechanism comprises a normal cylinder and a normal jack which are coaxially arranged on the rigid frame structure, and the normal cylinder and the normal jack are both hollow and are used for placing a normal impact disturbance module; the tangential loading mechanism comprises a tangential oil cylinder and a tangential jack which are coaxially arranged on the rigid frame structure, and the tangential oil cylinder and the tangential jack are in a hollow design and are used for placing the tangential impact disturbance module.
Preferably, the normal impact disturbance module comprises a horizontal truss, a vertical truss, a drop hammer connecting rod, a drop hammer and a normal incidence rod which are arranged on a rigid frame structure, wherein the horizontal truss and the vertical truss form an inverted U-shaped frame, the drop hammer connecting rod is movably arranged on the vertical truss, the normal incidence rod is arranged at the hollow position of a normal cylinder and a normal jack, the drop hammer is arranged on the drop hammer connecting rod and is opposite to the normal incidence rod, and the normal impact disturbance module changes normal impact disturbance energy by adjusting the height of the drop hammer. The force application of the drop hammer is measured through a strain gauge stuck on the normal incidence rod, and compared with the traditional light air gun force application mode, the device has the advantages of simple equipment and low running cost.
Preferably, the tangential impact disturbance module comprises a horizontal incidence rod, a protractor, a pendulum connecting rod, a pendulum, a vertical frame and a base, wherein the horizontal incidence rod is arranged at the hollow position of the tangential oil cylinder and the tangential jack, the vertical frame and the base are arranged on one side of the horizontal incidence rod, one end of the pendulum connecting rod is hinged to the top of the vertical frame, the heavy hammer is arranged at the bottom of the pendulum connecting rod and corresponds to the position of the horizontal incidence rod, the protractor is arranged at the top of the vertical frame and used for indicating the swing angle of the pendulum, and the tangential impact disturbance module changes tangential impact disturbance energy by adjusting the deflection angle of the pendulum. The pendulum impact loading has the advantages that the incident waveform required by the test can be directly obtained by changing the shape and the incident speed of the hammer head, the force application size of the pendulum impact loading can be measured through the strain gauge stuck on the normal incidence rod, and the pendulum impact loading device is simple in equipment and low in running cost.
Preferably, the normal direction energy storage module comprises an upper pressure head and a lower pressure head which are arranged in a relatively movable manner, a guide rod is detachably arranged between the upper pressure head and the lower pressure head, a central guide column is arranged on the upper pressure head, a central guide groove matched with the central guide column is arranged on the guide rod, an exhaust hole communicated with the bottom of the central guide groove is further formed in the guide rod, a plurality of belleville springs and gaskets are sleeved on the guide rod at positions between the corresponding upper pressure head and the lower pressure head, and the energy storage and rebound characteristics of the normal direction energy storage module and the tangential direction energy storage module are changed by adjusting the combination mode and the quantity of the belleville springs.
Preferably, a plurality of auxiliary guide posts are further arranged between the upper pressure head and the lower pressure head, auxiliary guide grooves are formed in the upper pressure head, corresponding to the auxiliary guide posts, and the central guide posts are matched with the central guide grooves; the auxiliary guide post is matched with the auxiliary guide groove; and polytetrafluoroethylene layers are arranged on the outer side walls of the central guide column and the auxiliary guide column, the central guide column and the auxiliary guide column ensure that the upper pressure head and the lower pressure head are always in parallel, and the stress surface of the structural surface sample is in uniform distribution load stress state.
Preferably, the rigid frame structure is further provided with a normal direction measuring system and a tangential direction measuring system, the normal direction measuring system and the tangential direction measuring system comprise a normal direction displacement sensor, a normal direction deformation sensor, a tangential direction displacement sensor and a tangential direction deformation sensor, the normal direction measuring system and the tangential direction displacement sensor are respectively used for measuring normal direction loading capacity and tangential direction testing machine loading capacity and structural surface deformation capacity, deformation capacity of the normal direction energy storage module and the tangential direction energy storage module can be obtained by making difference between the testing machine loading capacity and the structural surface deformation capacity, and then stored elastic energy is calculated. The normal direction and the tangential direction both adopt LVDT linear displacement sensors, and the working principle is that an iron core movable transformer, namely, an iron core moves in a coil to generate induced electromotive force, and the voltage and the displacement of the iron core form a linear relation.
Preferably, the normal displacement sensor is fixed on the normal jack; the normal deformation sensor is fixed on the rigid frame structure; the tangential displacement sensor is fixed on the tangential jack; the tangential deformation sensor is fixed to a rigid frame structure.
Preferably, an upper clamp of the clamping module is connected with the upper half part of the structural surface sample and the normal energy storage module to play a role in transmitting normal load; the lower clamp of the clamping module is connected with the lower half part of the structural surface sample and the tangential energy storage module to play a role in transferring tangential load.
A method for testing shear instability of a rock structural face, the method comprising the steps of:
(S1) sample preparation: cutting a rock sample collected on site into cube rock blocks with different sizes and numbers according to test requirements, and splitting along the middle part of the cube rock block by using a Brazil splitting method to obtain a fresh rock structural surface sample;
(S2) sample loading: and (3) loading the rock structural surface sample subjected to sample preparation in the step (S1) into an upper clamp and a lower clamp of a shear instability tester, so that the rock structural surface sample is centered and placed on a loading platform, the normal loading mechanism is ensured to pass through the central axis of the rock structural surface sample, and errors caused by eccentric loading are avoided.
(S3) instrument installation and connection: the shear instability tester is provided with detection instruments such as a normal displacement sensor, a tangential displacement sensor, a normal deformation sensor, a tangential deformation sensor, an acoustic emission probe, a high-speed camera, a speckle measurement system and the like;
(S4) applying normal and tangential loads: applying a certain normal load and keeping unchanged, then applying a certain tangential load and keeping unchanged, and simulating the stress state of the structural surface of the construction site;
(S5) applying a normal or tangential impact load: applying a certain normal or tangential impact load until the structural surface sample is subjected to shear instability damage; the judgment criteria for shear destabilization failure are: when the structural surface sample generates relatively obvious relative shearing displacement of 1-5mm, the shearing load generates obvious drop phenomenon after reaching the peak value;
(S6) drawing and analyzing a test curve: according to the test data, drawing a shear stress-displacement curve, a shear stress-time curve, a normal stress-displacement curve, a normal stress-time curve and a shear displacement-normal displacement curve of the rock structural surface, and carrying out combined analysis on the shear stress-displacement curve, the shear stress-time curve, the shear displacement-normal displacement curve, acoustic emission data such as acoustic emission energy, ringing count and event number and speckle data, so as to further reveal the shear instability characteristic of the rock structural surface.
The invention has the beneficial effects that: the invention provides a rock structural surface shear instability testing machine and a shear instability testing method, which can complete a conventional rock structural surface direct shear test and acquire a rock structural surface shear full stress-displacement curve under constant loading rate; and the destabilization sliding behavior of the rock structural surface is reproduced by adding the energy storage module, the impact disturbance module and utilizing the shear destabilization testing method, so that test conditions are further provided for the research work. In the underground mining process, the structural surface in the rock body is in a dynamic and static load superposition state, and the static load can be decomposed into static loads tangential to and normal to the structural surface; when mechanical construction or blasting disturbance exists, the generated dynamic load can be decomposed into dynamic loads tangential to and normal to the structural surface. Under different static load conditions, the disturbance induction conditions of dynamic loads are different, and when the normal static load is small and the tangential static load is large, the dynamic disturbance induction threshold value of shear instability is the lowest; conversely, when the normal static load is large and the tangential static load is small, the dynamic disturbance induction threshold of shear instability is the highest. Accordingly, the rock structural surface shear instability testing machine provided by the invention is used for simulating the stress environment and state in the underground mining process, reproducing the rock structural surface instability sliding behavior and researching the shear instability disturbance induction conditions of the structural surface.
Drawings
FIG. 1 is a schematic diagram of a rock structural surface shear instability tester according to the present invention;
FIG. 2 is a schematic diagram of an energy storage module;
the device comprises a 1-rigid frame structure, a 2-normal cylinder, a 3-tangential cylinder, a 4-normal jack, a 5-tangential jack, a 6-normal displacement sensor, a 7-tangential displacement sensor, an 8-normal deformation sensor, a 9-tangential deformation sensor, a 10-upper clamp, a 11-lower clamp, a 12-normal roller, a 13-tangential roller, a 14-rock structural surface sample, a 15-normal energy storage module, a 16-tangential energy storage module, a 17-horizontal truss, a 18-vertical truss, a 19-drop hammer connecting rod, a 20-drop hammer, a 21-normal incidence rod, a 22-horizontal incidence rod, a 23-protractor, a 24-pendulum hammer connecting rod, a 25-pendulum hammer, a 26-vertical frame, a 27-base, a 28-upper press head, a 29-butterfly spring, a 30-polytetrafluoroethylene layer, a 31-guide rod, a 32-gasket, a 33-lower press head, a 34-center guide post, a 35-center guide groove, a 36-thread groove, a 37-38-auxiliary guide post, a 39-vent hole, a 40-auxiliary guide groove.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The core of the invention is to provide a rock structural surface shear instability testing machine and a shear instability testing method, based on a traditional shear instrument, a Cook stiffness criterion and rock dynamics are used as theoretical basis, the loading stiffness of the testing machine is changed by adding an energy storage module, the energy storage characteristic and rebound behavior of a surrounding rock mass are simulated, the dynamic disturbance effect in the construction process is simulated by adding a normal and tangential impact disturbance module, the shear instability process of the rock structural surface is recorded by adopting a high-frequency sensor in the test engineering, and finally the rock structural surface shear instability testing machine is provided, and a complete shear instability testing method is provided.
Example 1:
1-2, a rock structural surface shear instability testing machine comprises a rigid frame structure 1, a clamping module, a normal loading mechanism, a tangential loading mechanism, a normal impact disturbance module, a tangential impact disturbance module, a normal energy storage module and a tangential energy storage module;
the clamping module is movably arranged on the rigid frame structure and is used for clamping the rock structural surface sample 14; the clamping module comprises an upper clamp 10 for clamping the upper half part of the rock structural surface sample and a lower clamp 11 for clamping the lower half part of the rock structural surface sample, the upper clamp 10 is connected with the movable ends of the normal loading mechanism and the normal impact disturbance mechanism, the lower clamp is connected with the movable ends of the tangential loading mechanism and the tangential impact disturbance mechanism, a normal roller 12 is rotatably arranged on the rigid frame structure corresponding to the upper clamp position, a tangential roller is rotatably arranged on the rigid frame structure corresponding to the upper clamp position, and the normal roller and the tangential roller are used for reducing friction and improving measurement accuracy; the upper fixture and the lower fixture comprise different models and correspond to rock structural surfaces with different sizes, and the research function of the structural surface scale utility can be realized. The upper clamp of the clamping module is connected with the upper half part of the structural surface sample and the normal energy storage module to play a role in transmitting normal load; the lower clamp of the clamping module is connected with the lower half part of the structural surface sample and the tangential energy storage module to play a role in transferring tangential load.
The normal loading mechanism is fixedly arranged at the top of the rigid frame structure and is used for applying a normal load to a rock structural surface sample, and the working end of the normal loading mechanism is connected with the clamping module; the normal loading mechanism comprises a normal cylinder 2 and a normal jack 4 which are coaxially arranged on the rigid frame structure, and the normal cylinder and the normal jack are both hollow and are used for placing a normal impact disturbance module; the tangential loading mechanism is fixedly arranged on the side surface of the rigid frame structure and is used for applying tangential load to the test sample for clamping the rock structural surface, and the working end of the tangential loading mechanism is connected with the clamping module; the tangential loading mechanism comprises a tangential oil cylinder 3 and a tangential jack 6 which are coaxially arranged on the rigid frame structure, and the tangential oil cylinder and the tangential jack adopt a hollow design and are used for placing the tangential impact disturbance module.
The normal impact disturbance module is installed in the rigid frame structure outside and corresponds normal loading mechanism position, the tangential impact disturbance module is installed in the rigid frame structure outside and corresponds tangential loading mechanism position, the normal impact disturbance module is including installing horizontal truss 17 on the rigid frame structure, vertical truss 18, drop hammer connecting rod 19, drop hammer 20 and normal incidence pole 21, wherein horizontal truss, vertical truss forms the U type frame that falls, drop hammer connecting rod movable mounting is on vertical truss, normal incidence pole is installed in the hollow position department of normal hydro-cylinder, normal jack, drop hammer is installed on drop hammer connecting rod just to normal incidence pole position department, normal impact disturbance module changes normal impact disturbance energy through adjusting the height of drop hammer. The tangential impact disturbance module comprises a horizontal incidence rod 22, a protractor 23, a pendulum connecting rod 24, a pendulum 25, a vertical frame 26 and a base 27, wherein the horizontal incidence rod is arranged at the hollow position of the tangential oil cylinder and the tangential jack, the vertical frame and the base are arranged on one side of the horizontal incidence rod, one end of the pendulum connecting rod is hinged to the top of the vertical frame, a heavy hammer is arranged at the bottom of the pendulum connecting rod and corresponds to the position of the horizontal incidence rod, the protractor is arranged at the top of the vertical frame and used for indicating the swing angle of the pendulum, and the tangential impact disturbance module changes tangential impact disturbance energy by adjusting the deflection angle of the pendulum. The normal impact disturbance module is used for applying normal impact load and tangential impact load to the rock structural surface sample and simulating impact disturbance in the construction process. The normal and tangential loading mechanisms are matched with the normal and tangential impact disturbance modules to simulate and research disturbance induction conditions of shear instability under different stress states;
the normal energy storage module and the tangential energy storage module are respectively connected with the normal loading mechanism and the tangential loading mechanism and are used for simulating the energy storage effect and the rebound effect of the surrounding rock mass and the shear instability and damage behavior of the structural surface. The normal energy storage module 15 and the tangential energy storage module 16 respectively comprise an upper pressure head 28 and a lower pressure head 33 which are relatively movably arranged, a guide rod is detachably arranged between the upper pressure head and the lower pressure head, in the embodiment, a threaded rod 37 is arranged on the lower pressure head, a thread groove 36 matched with the threaded rod 37 is formed in the bottom of the guide rod, a central guide column is arranged on the upper pressure head, a central guide groove 35 matched with the central guide column 34 is arranged on the guide rod 31, an exhaust hole 39 communicated with the bottom of the central guide column is also arranged on the guide rod, a plurality of butterfly springs 29 and gaskets 32 are sleeved on the guide rod at positions corresponding to the positions between the upper pressure head and the lower pressure head, and the energy storage and rebound characteristics of the normal energy storage module and the tangential energy storage module are changed by adjusting the combination mode and the number of the butterfly springs; the butterfly spring adopts different combination modes of superposition, involution, compounding and the like to obtain the variable stiffness elastic energy storage device with different mechanical properties. In order to reduce friction between the belleville springs, lubricating liquid is smeared between the belleville springs, and the influence of friction on the mechanical property of the variable-rigidity elastic energy storage device is eliminated. The gasket is located between the base and the belleville spring, a certain number of gaskets can be selected to be overlapped according to requirements, the gaskets are used for guaranteeing that the belleville spring has enough deformation space, and the adjusting method of the energy storage and rebound characteristics of the normal and tangential energy storage modules can be described in the patent document: CN109253932a is a specific content in a method for testing rock instability by using the variable-stiffness elastic energy storage device.
As a preferred embodiment, a plurality of auxiliary guide posts 38 are also arranged between the upper pressure head and the lower pressure head, auxiliary guide slots 40 are arranged on the upper pressure head corresponding to the positions of the auxiliary guide posts, and the central guide posts are matched with the central guide slots; the auxiliary guide post is matched with the auxiliary guide groove; and polytetrafluoroethylene layers 30 are arranged on the outer side walls of the central guide column and the auxiliary guide column, the central guide column and the auxiliary guide column ensure that the upper pressure head and the lower pressure head are always in a parallel state, and the stress surface of the structural surface sample is in a uniformly distributed load stress state.
The rigid frame structure is also provided with a normal direction and tangential direction measuring system, the normal direction and tangential direction measuring system comprises a normal direction displacement sensor 6, a normal direction deformation sensor 8, a tangential direction displacement sensor 7 and a tangential direction deformation sensor 9, and the normal direction displacement sensor is fixed on a normal direction jack; the normal deformation sensor is fixed on the rigid frame structure; the tangential displacement sensor is fixed on the tangential jack; the tangential deformation sensor is fixed on the rigid frame structure and is used for measuring normal and tangential testing machine loading capacity and structural surface deformation capacity respectively, and the deformation capacity of the normal and tangential energy storage modules can be obtained by making difference between the testing machine loading capacity and the structural surface deformation capacity, so that the stored elastic energy can be calculated.
A rock structural surface shear instability test method comprises the following steps:
(S1) sample preparation: cutting a rock sample collected on site into cube rock blocks with different sizes and numbers according to test requirements, and splitting along the middle part of the cube rock block by using a Brazil splitting method to obtain a fresh rock structural surface sample;
(S2) sample loading: and (3) loading the rock structural surface sample subjected to sample preparation in the step (S1) into an upper clamp and a lower clamp of a shear instability tester, so that the rock structural surface sample is centered and placed on a loading platform, the normal loading mechanism is ensured to pass through the central axis of the rock structural surface sample, and errors caused by eccentric loading are avoided.
(S3) instrument installation and connection: and detecting instruments such as a normal displacement sensor, a tangential displacement sensor, a normal deformation sensor, a tangential deformation sensor, an acoustic emission probe, a high-speed camera, a speckle measurement system and the like are arranged on the shear instability tester.
(S4) applying normal and tangential loads: applying a certain normal load and keeping unchanged, then applying a certain tangential load and keeping unchanged, and simulating the stress state of the structural surface of the construction site;
(S5) applying a normal or tangential impact load: applying a certain normal or tangential impact load until the structural surface sample is subjected to shear instability damage; the judgment criteria for shear destabilization failure are: when the structural surface sample generates relatively obvious relative shearing displacement of 1-5mm, the shearing load generates obvious drop phenomenon after reaching the peak value;
(S6) drawing and analyzing a test curve: according to the test data, drawing a shear stress-displacement curve, a shear stress-time curve, a normal stress-displacement curve, a normal stress-time curve and a shear displacement-normal displacement curve of the rock structural surface, and carrying out combined analysis on the shear stress-displacement curve, the shear stress-time curve, the shear displacement-normal displacement curve, acoustic emission data such as acoustic emission energy, ringing count and event number and speckle data, so as to further reveal the shear instability characteristic of the rock structural surface.
Finally, it should be noted that: the foregoing description is only illustrative of the preferred embodiments of the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements or changes may be made without departing from the spirit and principles of the present invention.
Claims (10)
1. The utility model provides a rock structure face shear instability testing machine which characterized in that: the device comprises a rigid frame structure, a clamping module, a normal loading mechanism, a tangential loading mechanism, a normal impact disturbance module, a tangential impact disturbance module, a normal energy storage module and a tangential energy storage module;
the clamping module is movably arranged on the rigid frame structure and is used for clamping the rock structural surface sample;
the normal loading mechanism is fixedly arranged at the top of the rigid frame structure and is used for applying a normal load to a rock structural surface sample, and the working end of the normal loading mechanism is connected with the clamping module;
the tangential loading mechanism is fixedly arranged on the side surface of the rigid frame structure and is used for applying tangential load to the rock structural surface clamping sample, and the working end of the tangential loading mechanism is connected with the clamping module;
the normal impact disturbance module is arranged at the position of the corresponding normal loading mechanism at the outer side of the rigid frame structure, the tangential impact disturbance module is arranged at the position of the corresponding tangential loading mechanism at the outer side of the rigid frame structure, and the normal impact disturbance module and the tangential impact disturbance module are used for applying normal impact load and tangential impact load to the rock structural surface sample and simulating impact disturbance in the construction process;
the normal and tangential loading mechanisms are matched with the normal and tangential impact disturbance modules to simulate and research disturbance induction conditions of shear instability under different stress states;
the normal energy storage module and the tangential energy storage module are respectively connected with the normal loading mechanism and the tangential loading mechanism and are used for simulating the energy storage effect and the rebound effect of the surrounding rock mass and the shear instability and damage behavior of the structural surface.
2. The rock structural face shear instability testing machine of claim 1 wherein: the clamping module comprises an upper clamp for clamping the upper half part of the rock structural surface sample and a lower clamp for clamping the lower half part of the rock structural surface sample, the upper clamp is connected with the movable ends of the normal loading mechanism and the normal impact disturbance mechanism, the lower clamp is connected with the movable ends of the tangential loading mechanism and the tangential impact disturbance mechanism, a normal roller is rotatably arranged on the rigid frame structure corresponding to the upper clamp, a tangential roller is rotatably arranged on the rigid frame structure corresponding to the upper clamp, and the normal roller and the tangential roller are used for reducing friction and improving measurement accuracy; the upper clamp and the lower clamp comprise different models and correspond to rock structural surfaces with different sizes, so that the research function of the dimensional utility of the structural surfaces can be realized; the upper clamp of the clamping module is connected with the upper half part of the structural surface sample and the normal energy storage module to play a role in transmitting normal load; the lower clamp of the clamping module is connected with the lower half part of the structural surface sample and the tangential energy storage module to play a role in transferring tangential load.
3. The rock structural face shear instability testing machine of claim 1 wherein: the normal loading mechanism comprises a normal cylinder and a normal jack which are coaxially arranged on the rigid frame structure, and the normal cylinder and the normal jack are both of hollow design and are used for placing a normal impact disturbance module; the tangential loading mechanism comprises a tangential oil cylinder and a tangential jack which are coaxially arranged on the rigid frame structure, and the tangential oil cylinder and the tangential jack are in a hollow design and are used for placing the tangential impact disturbance module.
4. A rock structural face shear instability testing machine according to claim 3, wherein: the normal impact disturbance module comprises a horizontal truss, a vertical truss, a drop hammer connecting rod, a drop hammer and a normal incidence rod which are arranged on a rigid frame structure, wherein the horizontal truss and the vertical truss form an inverted U-shaped frame, the drop hammer connecting rod is movably arranged on the vertical truss, the normal incidence rod is arranged at the hollow position of a normal cylinder and a normal jack, the drop hammer is arranged on the drop hammer connecting rod and is opposite to the normal incidence rod, and the normal impact disturbance module changes normal impact disturbance energy by adjusting the height of the drop hammer.
5. A rock structural face shear instability testing machine according to claim 3, wherein: the tangential impact disturbance module comprises a horizontal incidence rod, a protractor, a pendulum connecting rod, a pendulum, a vertical frame and a base, wherein the horizontal incidence rod is arranged at the hollow position of a tangential oil cylinder and a tangential jack, the vertical frame and the base are arranged on one side of the horizontal incidence rod, one end of the pendulum connecting rod is hinged to the top of the vertical frame, the heavy hammer is arranged at the bottom of the pendulum connecting rod and corresponds to the position of the horizontal incidence rod, the protractor is arranged at the top of the vertical frame and used for indicating the swing angle of the pendulum, and the tangential impact disturbance module changes tangential impact disturbance energy by adjusting the deflection angle of the pendulum.
6. The rock structural face shear instability testing machine of claim 1 wherein: the normal direction energy storage module comprises an upper pressure head and a lower pressure head which are arranged in a relatively movable manner, a guide rod is detachably arranged between the upper pressure head and the lower pressure head, a central guide column is arranged on the upper pressure head, a central guide groove matched with the central guide column is arranged on the guide rod, an exhaust hole communicated with the bottom of the central guide groove is further formed in the guide rod, a plurality of belleville springs and gaskets are sleeved on the guide rod at positions between the upper pressure head and the lower pressure head, and the energy storage and rebound characteristics of the normal direction energy storage module and the tangential direction energy storage module are changed by adjusting the combination mode and the quantity of the belleville springs.
7. The rock face shear instability testing machine of claim 6, wherein: a plurality of auxiliary guide posts are arranged between the upper pressure head and the lower pressure head, auxiliary guide grooves are formed in the positions, corresponding to the auxiliary guide posts, of the upper pressure head, and the central guide posts are matched with the central guide grooves; the auxiliary guide post is matched with the auxiliary guide groove; and polytetrafluoroethylene layers are arranged on the outer side walls of the central guide column and the auxiliary guide column, the central guide column and the auxiliary guide column ensure that the upper pressure head and the lower pressure head are always in parallel, and the stress surface of the structural surface sample is in uniform distribution load stress state.
8. The rock structural face shear instability testing machine of claim 1 wherein: the rigid frame structure is also provided with a normal direction measuring system and a tangential direction measuring system, the normal direction measuring system and the tangential direction measuring system comprise a normal direction displacement sensor, a normal direction deformation sensor, a tangential direction displacement sensor and a tangential direction deformation sensor, the normal direction measuring system and the tangential direction displacement sensor are respectively used for measuring the loading capacity and the structural surface deformation capacity of the normal direction and the tangential direction, the deformation capacity of the normal direction energy storage module and the tangential direction energy storage module can be obtained by making difference between the loading capacity and the structural surface deformation capacity of the testing machine, and then the stored elastic energy is calculated.
9. The rock structural face shear instability testing machine of claim 8 wherein: the normal displacement sensor is fixed on the normal jack; the normal deformation sensor is fixed on the rigid frame structure; the tangential displacement sensor is fixed on the tangential jack; the tangential deformation sensor is fixed to a rigid frame structure.
10. A shear instability test method for a rock structural surface is characterized by comprising the following steps of: the method comprises the following steps:
(S1) sample preparation: cutting a rock sample collected on site into cube rock blocks with different sizes and numbers according to test requirements, and splitting along the middle part of the cube rock block by using a Brazil splitting method to obtain a fresh rock structural surface sample;
(S2) sample loading: loading the rock structural surface sample subjected to sample preparation in the step S1 into an upper clamp and a lower clamp of a shear instability tester, so that the rock structural surface sample is centered and placed on a loading platform, and a normal loading mechanism is ensured to pass through the central axis of the rock structural surface sample, so that errors caused by eccentric loading are avoided;
(S3) instrument installation and connection: the shear instability tester is provided with detection instruments such as a normal displacement sensor, a tangential displacement sensor, a normal deformation sensor, a tangential deformation sensor, an acoustic emission probe, a high-speed camera, a speckle measurement system and the like;
(S4) applying normal and tangential loads: applying a certain normal load and keeping unchanged, then applying a certain tangential load and keeping unchanged, and simulating the stress state of the structural surface of the construction site;
(S5) applying a normal or tangential impact load: applying a certain normal or tangential impact load until the structural surface sample is subjected to shear instability damage; the judgment criteria for shear destabilization failure are: when the structural surface sample generates relatively obvious relative shearing displacement of 1-5mm, the shearing load generates obvious drop phenomenon after reaching the peak value;
(S6) drawing and analyzing a test curve: according to the test data, drawing a shear stress-displacement curve, a shear stress-time curve, a normal stress-displacement curve, a normal stress-time curve and a shear displacement-normal displacement curve of the rock structural surface, and carrying out combined analysis on the shear stress-displacement curve, the shear stress-time curve, the shear displacement-normal displacement curve, acoustic emission data such as acoustic emission energy, ringing count and event number and speckle data, so as to further reveal the shear instability characteristic of the rock structural surface.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117232999A (en) * | 2023-11-10 | 2023-12-15 | 中国矿业大学(北京) | High-energy-level multi-mode power impact test system and method for underground engineering support system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117232999A (en) * | 2023-11-10 | 2023-12-15 | 中国矿业大学(北京) | High-energy-level multi-mode power impact test system and method for underground engineering support system |
| CN117232999B (en) * | 2023-11-10 | 2024-01-19 | 中国矿业大学(北京) | High-energy-level multi-mode power impact test system and method for underground engineering support system |
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