CN111089781A

CN111089781A - Rock shear test equipment and direct shear test method for rock test block

Info

Publication number: CN111089781A
Application number: CN202010045202.3A
Authority: CN
Inventors: 江权; 冯夏庭; 李邵军; 徐鼎平; 苏国韶; 晏飞; 邱士利
Original assignee: Wuhan Institute of Rock and Soil Mechanics of CAS
Current assignee: Wuhan Institute of Rock and Soil Mechanics of CAS
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2020-05-01
Anticipated expiration: 2040-01-16
Also published as: CN111089781B

Abstract

The invention relates to rock shear test equipment and a direct shear test method for a rock test block. The rock shearing test equipment comprises a main frame, a shearing box, a vertical loading device, a horizontal loading device and a test assembly. The first half box and the second half box of the shearing box are opposite and arranged in a stacked mode so as to form a containing space with adjustable volume in a surrounding mode. The vertical loading device comprises a normal loading oil cylinder. The horizontal loading device comprises a horizontal loading oil cylinder. The horizontal loading oil cylinder comprises a second fixed end and a second action end. The test assembly includes a plurality of normal load sensors mounted to the first actuation end. Any one of the plurality of normal load sensors is used to collect normal stress values of the rock test block. The measuring ranges of the normal load sensors are different. Therefore, the rock shearing test equipment can perform direct shearing tests on the rock test blocks with different sizes and specifications, and the accuracy of the direct shearing test result is higher.

Description

Rock shear test equipment and direct shear test method for rock test block

Technical Field

The invention relates to the technical field of geotechnical engineering, in particular to rock shearing test equipment and a direct shearing test method for a rock test block.

Background

With the development of large-scale geotechnical engineering to deep rock masses, the safety problem of deep geotechnical engineering is increasingly emphasized. Deep engineering rock masses usually contain natural structural faces with different shapes and sizes, the positions of the natural structural faces usually have high ground stress, the strength of the rock mass is reduced by the existence of the structural faces, and therefore large-scale and severe geological disasters are likely to be induced by the damage of the structural faces. Therefore, the development of the indoor direct shear test is a common means for studying the stress, deformation and failure mechanism of the structural surface in the rock mass under high stress. The rock shearing test equipment is indoor direct shearing test equipment which is commonly used at present.

At present, in order to more comprehensively research the stress, deformation and failure mechanism of a rock structural surface under high stress, direct shear tests on rock test blocks with different sizes or specifications are required, and the direct shear tests on the rock test blocks in different normal stiffness loading modes are urgently required to be carried out. However, when the conventional rock shear test equipment is used for performing direct shear tests on rock test blocks with different sizes and specifications, the problems of low stress and displacement measurement precision, simple normal loading mode and the like exist, the accuracy of direct shear test results is influenced, and the discovery of shear mechanical properties and new phenomena penetrating into the rock test blocks is also restricted.

Disclosure of Invention

Therefore, the rock shear test equipment capable of improving the test result accuracy and the shear test method for the rock test block are needed to be provided aiming at the problems that the test result accuracy of the conventional direct shear test is not high and the normal stiffness loading mode is lacked.

A rock shear test apparatus comprising:

the main frame comprises a base and a support arranged on the base, and the connecting line direction of the support and the base is a first direction;

the shearing box comprises a first half box and a second half box, the first half box and the second half box are opposite and stacked to form an accommodating space for accommodating a rock test block in a surrounding manner, the accommodating space is adjustable in volume, and the second half box is arranged on the base;

the vertical loading device comprises a normal loading oil cylinder, the normal loading oil cylinder comprises a first fixed end and a first action end which are opposite, the first fixed end is installed at one end, far away from the base, of the support, and the first action end is connected with the first half box and can drive the first half box to move along the first direction;

the horizontal loading device comprises a horizontal loading oil cylinder, the horizontal loading oil cylinder comprises a second fixed end and a second action end, the second fixed end is installed on the base, and the second action end is connected with the second half box and can drive the second half box to slide along a second direction perpendicular to the first direction; and

the testing assembly comprises a plurality of normal load sensors installed at a first action end, any one of the normal load sensors is used for collecting the normal stress value of the rock test block, and the measuring ranges of the normal load sensors are different.

In one embodiment, the bracket comprises a connecting seat and at least three parallel and spaced columns, the at least three columns are arranged on one side of the connecting seat facing the base along the circumferential direction of the connecting seat, one end of each column far away from the connecting seat is fixedly connected with the base, and the first fixing end is fixedly connected with the connecting seat.

In one embodiment, the main frame further comprises a rail mounted on the base, and the rail extends in the second direction, the second cartridge half being slidably mounted on the rail;

preferably, the guide rail is two, two the guide rail is parallel and the interval sets up, every the guide rail is kept away from the one end of base is along deviating from another the direction of guide rail is buckled, so that the guide rail is the shape of falling L, the bottom of the half box of second be provided with two respectively with guide rail assorted spout, and two the guide rail install slidable respectively in two in the spout.

In one embodiment, the first half box is a plurality of, and is a plurality of the first half box can be nested in proper order from inside to outside, and is a plurality of the opening direction of the first half box is unanimous, the second half box is a plurality of, and is a plurality of the second half box can be nested in proper order from inside to outside, and is a plurality of the opening direction of the second half box is unanimous, and is a plurality of the first half box corresponds one-to-one respectively with a plurality of second half boxes, and every the open-ended one end of the first half box sets up with corresponding the open-ended one end of the second half box relatively.

In one embodiment, the plurality of first half-boxes comprise a first shell and a first containing shell which can be embedded in the first shell, and the first action end is connected with the first shell;

the plurality of second half boxes comprise second shells and second containing shells capable of being embedded in the second shells, the second containing shells and the first containing shells can be arranged oppositely and in a stacked mode to enclose and form the containing space, the second action ends are connected with the second shells and can drive the second containing shells to move along the second direction;

horizontal loading device still includes horizontal drive spare, horizontal drive spare includes third stiff end and third action end, the third stiff end is fixed in the base, the third action end with the second holds the shell and connects, and can drive the second holds the shell and follows for the second shell moves the second direction.

In one embodiment, the horizontal loading device further includes a connecting assembly, the connecting assembly includes a first fixing member mounted on the second fixing end, a second fixing member mounted on the first half box, and a plurality of connecting rods spaced along the first direction, the first fixing member and the second fixing member are disposed opposite to each other and spaced apart from each other, and two ends of each connecting rod are respectively movably connected to the first fixing member and the second fixing member.

In one embodiment, the test assembly further comprises a tangential load sensor mounted at the second action end and used for measuring the horizontal stress value of the rock test block.

In one embodiment, the test assembly further includes a normal displacement sensor and a horizontal displacement sensor, the normal displacement sensor is mounted on the first half box and used for measuring a normal displacement value of the first half box in the direct shear test process, and the horizontal displacement sensor is mounted on the second half box and used for measuring a tangential displacement value of the second half box in the direct shear test process.

In one embodiment, the hydraulic control system further comprises a hydraulic controller, wherein the hydraulic controller is electrically connected with the normal loading oil cylinder and the tangential loading oil cylinder respectively and controls the first action end and the second action end to operate according to a preset instruction;

preferably, the rock shear test equipment further comprises a digital controller, wherein the digital controller is in communication connection with any one of the normal load sensors, the tangential load sensor, the normal displacement sensor and the horizontal displacement sensor respectively, and calculates the stress parameter and the displacement parameter of the rock test block according to the normal stress value, the tangential stress value, the normal displacement value and the tangential displacement value.

Above-mentioned shear test equipment, during the use, can adjust the volume of shearing box accommodation space according to the size of rock test block for the clamping of the rock test block of different size specifications in shearing box is all comparatively firm, and is comparatively steady in order to guarantee the direct shear test process, has improved the accuracy of direct shear test result effectively. Furthermore, the normal load sensors can be freely switched, and the normal load sensor with the measuring range matched with the rock test block to be tested can be selected before the direct shear test, so that the accurate normal load measurement can be carried out on the structural surface of the rock test block in the direct shear test process, and the accuracy of the direct shear test result is further improved. Therefore, the rock shear test equipment can be used for carrying out direct shear tests on rock test blocks with different sizes and specifications, and the accuracy of direct shear test results is higher.

A direct shear test testing method for a rock test block comprises the following steps:

placing a rock test block in a shear box, wherein the shear box comprises a first half box and a second half box which are oppositely and stacked, and the connection direction of the first half box and the second half box is a first direction;

applying an initial normal load to the first half box by using a normal loading oil cylinder so as to enable the first half box to move along the first direction until the structural surface of the rock test block reaches a preset state;

applying a normal load to the first half box by using the normal loading oil cylinder, and simultaneously driving the second half box to move along a second direction perpendicular to the first direction by using a horizontal loading oil cylinder until the displacement value of the second half box reaches a preset horizontal displacement value, wherein the normal load value is according to an equation: f_n ^t+1＝F_n ^t+Δh_t+1And K is obtained by calculation,

wherein the content of the first and second substances,

k is a normal stiffness coefficient, t is a time value, and the increment of the normal displacement in the unit sampling interval from the real-time measurement of the normal displacement sensor LVDT from the time t to the time t +1 is delta h_t+1；

And measuring a normal load value, a shear load value, a normal displacement value and a shear displacement value of the rock test block structural surface in real time by using a normal load sensor, a tangential load sensor, a normal displacement sensor and a horizontal displacement sensor, and acquiring stress parameters and displacement parameters required by the test according to the normal load value, the tangential load value, the normal displacement value and the shear displacement value.

In the direct shear test method for the rock test block, the equation F is utilized in the direct shear test process_n ^t+1＝F_n ^t+Δh_t+1K is calculated to obtain a normal load value, so that the rigidity cannot greatly fluctuate violently when the normal loading oil cylinder applies the normal load to the first half box, the direct shear test process is stable, the accuracy of load measurement and displacement measurement data in the direct shear test process is further ensured, and the accuracy of the direct shear test result is effectively improved.

Drawings

FIG. 1 is a schematic diagram of a rock shear test apparatus according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of a portion of the rock shear test apparatus shown in FIG. 1;

FIG. 3 is a right side view of the rock shear test apparatus of FIG. 2;

FIG. 4 is a top plan view of the rock shear test apparatus of FIG. 2;

FIG. 5 is a schematic view of the rock shear test apparatus of FIG. 2 with normal load sensors in an installed condition;

FIG. 6 is a schematic view of the rock shear test apparatus of FIG. 2 with a plurality of normal load sensors in another installation configuration;

FIG. 7 is a schematic view of the installation of the guide rail in the rock shear test apparatus of FIG. 2;

FIG. 8 is a schematic view of the shear box of the rock shear test apparatus of FIG. 2 shown in a state in which the second containment shell is not pushed out of the second outer shell;

FIG. 9 is a schematic view of the rock shear testing apparatus of FIG. 2 in a state in which the shear box is pushed out of the second housing shell;

FIG. 10 is a flow chart of a direct shear test method for a rock test block according to a preferred embodiment of the present invention.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

When an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present, unless otherwise specified. It will also be understood that when an element is referred to as being "between" two elements, it can be the only one between the two elements, or one or more intervening elements may also be present.

Where the terms "comprising," "having," and "including" are used herein, another element may be added unless an explicit limitation is used, such as "only," "consisting of … …," etc. Unless mentioned to the contrary, terms in the singular may include the plural and are not to be construed as being one in number.

Furthermore, the drawings are not 1: 1, and the relative dimensions of the various elements in the figures are drawn for illustration only and not necessarily to true scale.

Referring to fig. 1, the rock shear test apparatus 10 according to the preferred embodiment of the present invention includes a main frame 100, a shear box 200, a vertical loading device 300, a horizontal loading device 400, and a test assembly 500.

Referring to fig. 2 and 3, the main frame 100 includes a base 110 and a support 120 disposed on the base 110. The direction of the line connecting the holder 120 and the base 110 is the first direction 20. The main frame 100 mainly plays a supporting role. The first direction 20 is a vertical direction when the rock shear test apparatus 10 is located in a horizontal plane.

The shear box 200 includes a first box half 210 and a second box half 220. The first half-case 210 and the second half-case 220 are disposed opposite to each other and stacked to enclose an accommodating space (not shown) for accommodating a rock test block. The volume of the accommodating space is adjustable. Second box half 220 is mounted to base 110. The volume of the accommodating space can be adjusted by installing an elastic pad in each of the first half-case 210 and the second half-case 220, or by nesting the first half-case 210 and the second half-case 220, which are smaller in size, in the first half-case 210 and the second half-case 220, respectively.

Because the volume of the accommodating space is adjustable, the shearing box 200 can clamp rock test blocks with different sizes and specifications, and is favorable for comprehensively researching the stress, deformation and failure mechanism of the rock structural surface under high stress. And accommodation space's volume is adjustable for the clamping of the rock test block of different dimensions all is comparatively firm in shearing box 200, thereby makes the direct shear test process comparatively steady, has improved the accuracy of direct shear test result effectively.

The vertical loading device 300 includes a normal load cylinder 310. The normal load cylinder 310 includes a first fixed end 311 and a first actuating end 312. The first fixing end 311 is mounted at an end of the bracket 120 away from the base 110. The first actuating end 312 is coupled to the first cassette half 210 and drives the first cassette half 210 in the first direction 20. When the rock shear test apparatus 10 is in a horizontal plane, the normal load cylinder 310 may drive the first cassette half 210 to move in a vertical direction. It is understood that in other embodiments, the normal loading cylinder 310 may also be a driving motor, a servo motor, an electric strut, etc., as long as the first cartridge half 210 can be driven to move along the first direction 20.

Referring also to fig. 4, the horizontal loading device 400 includes a horizontal loading cylinder 410. The horizontal loading cylinder 410 includes a second fixed end 411 and a second actuating end 412. The second fixing end 411 is mounted on the base 110. The second actuating end 412 is coupled to the second half-case 220 and drives the second half-case 220 to slide in a second direction 30 perpendicular to the first direction 20. When the rock shear test apparatus 10 is in a horizontal position, the second direction 30 perpendicular to the first direction 20 is a horizontal direction, so that the second actuation end 412 can drive the second half-box 220 to slide in the horizontal direction. It is understood that in other embodiments, the horizontal loading cylinder 410 may also be a driving motor, a clothes motor, an electric stay, etc., as long as the second half-box 220 can be driven to slide along the second direction 30.

The test assembly 500 includes a plurality of normal load sensors 510 mounted to the first actuation end 312. Any one of the plurality of normal load sensors 510 is used to collect normal pressure values for the rock test block. The measurement ranges of each normal load sensor 510 are different. Therefore, the normal load sensors 510 can be freely switched, and the normal load sensors 510 with the measuring ranges matched with the size specifications of the rock test block can be selected to measure the normal load according to the size specifications of the rock test block during the direct shear test, so that the accuracy of the measuring result in the direct shear test process is ensured.

Referring to fig. 5 and 6, in particular, the vertical loading device 300 further includes a plurality of locking pads 550 corresponding to the plurality of normal load sensors 510 one to one. Each locking pad 550 is connectable at one end to a corresponding normal load cell 510 and at the other end to the second cassette half 220. Thus, each normal load sensor 510 is mounted at a different distance from the second half case 220, and thus each locking pad 550 has a different structure as long as it can function as a connection. Thus, each locking pad 550 is removably coupled between the corresponding normal load cell 510 and the second cassette half 220 to effect coupling of the second cassette half 220 to the first actuating end 312. When switching among the normal load sensors 510 is required, only the two ends of the locking pad 550 need to be detached from the corresponding normal load sensors 510 and the second half box 220, and the two ends of the other locking pad 550 need to be connected with the corresponding normal load sensors 510 and the second half box 220, so that switching among the normal load sensors 510 is convenient.

The process of using the rock shear test equipment 10 to perform the direct shear test on the rock test block is as follows:

(1) according to the size of the rock test block to be tested, the volume of the accommodating space of the shearing box 200 is adjusted, and the rock test block is firmly clamped in the accommodating space of the shearing box 200.

(2) An initial load is applied to the rock test block in the shear box 200 by the normal loading cylinder 310 to drive the first half box 210 to move to a preset normal position along the first direction 20, and the stress value of the initial load is a constant value.

(3) The second cassette half 220 is driven to move in the second direction 30 by the horizontal loading cylinder 410 until the displacement value of the second cassette half 220 reaches the preset displacement value.

(4) During the movement of the second half box 220 in the second direction 30, the normal load sensor 510 is used to measure the normal stress value of the rock structural face, and test parameters for a direct shear test of the rock test block are obtained according to the normal stress value.

Therefore, the rock shearing test equipment 10 can be used for performing direct shearing tests on rock test blocks with different sizes and specifications, and the accuracy of test results obtained by the direct shearing tests is higher.

Referring to fig. 4, in the present embodiment, the bracket 120 includes a connecting seat 121 and at least three columns 122 arranged in parallel and at an interval. At least three vertical posts 122 are disposed on one side of the connection seat 121 facing the base 110 along the circumferential direction of the connection seat 121. One end of each upright 122 away from the connecting base 121 is fixedly connected with the base 110. Thus, the bracket 120 has a frame structure including a connecting base 121 and a plurality of vertical posts 122. The first fixing end 311 is fixedly connected to the connecting base 121. Thus, the normal load cylinder 310 is mounted on the connection seat 121. Therefore, the arrangement of the plurality of upright posts 122 ensures that the stability of the normal loading oil cylinder 310 arranged on the connecting seat 121 in the direct shear test process is better, and the improvement of the accuracy of the direct shear test result is facilitated.

Specifically, the connecting seat 121 is a rectangular plate, and the number of the upright posts 122 is four. The four upright posts 122 are respectively disposed at four corners of the connecting seat 121.

Referring to fig. 3 and 4 again, in the present embodiment, the main frame 100 further includes a guide rail 130 mounted on the base 110. The guide rail 130 extends in the second direction 30. Second cassette half 220 is slidably mounted on rail 130. Therefore, the arrangement of the guide rail 130 can improve the running precision of the second half box 220 in the second direction 30, reduce the dragging resistance when the second half box 220 slides in the second direction 30 in the direct shear test process, ensure the high precision of the direct shear test load, and further improve the accuracy of the direct shear test result.

Referring to fig. 7, in the present embodiment, there are two guide rails 130. The two guide rails 130 are arranged in parallel and spaced apart. One end of each rail 130 remote from the base 110 is bent in a direction away from the other rail 130 so that the rails 130 have an inverted L-shape. The bottom of the second half-box 220 is provided with two sliding grooves (not shown) respectively matching with the guide rails 130. The two guide rails 130 are slidably installed in the two sliding grooves, respectively. Therefore, the two guide rails 130 are arranged, each guide rail 130 is arranged to be in an inverted L shape, the second half box 220 can be prevented from being horizontally laterally derailed and being separated from the guide rails 130 in the normal direction in the moving process, the equipment is damaged or personnel are injured, and the safety in the direct shear test process is effectively improved.

In the present embodiment, the first half casing 210 is plural. A plurality of first half-boxes 210 may be nested one inside the other. The openings of the plurality of first half cells 210 are aligned in the same direction. The second half case 220 is plural. A plurality of second box halves 220 may be nested one inside the other. The opening directions of the plurality of second half cases 220 coincide. The first half boxes 210 and the second half boxes 220 correspond to each other one by one. One end of each first half-case 210 opening is disposed opposite to one end of the corresponding second half-case 220 opening. Specifically, the first outer half-case 210 is coupled to the first actuating end 312, and the second outer half-case 220 is slidably coupled to the base 110. Therefore, the first half-boxes 210 and the second half-boxes 220 enclose an accommodating space, so that the volume of the accommodating space can be adjusted by increasing or decreasing the number of the first half-boxes 210 and the number of the second half-boxes 220.

Referring to fig. 8 and 9, in the present embodiment, the plurality of first half-cases 210 include a first housing 211 and a first accommodating case 212 nested in the first housing 211. The first actuating end 312 is connected to the first housing 311 and can drive the first housing 211 to move the first accommodating case 212 along the first direction 20.

The second half cases 220 respectively include a second housing 221 having a hollow structure and a second receiving case 222 nested in the second housing 221. The first receiving shell 212 and the second receiving shell 222 may be disposed opposite to each other and stacked to form a receiving space. The accommodating space is used for loading the rock test block. Thus, during the rock direct shear test, rock test pieces are placed in the first and second receiving

shells

212 and 222. The second actuating end 412 is connected to the second housing 221 and can drive the second housing 221 to move the second accommodating case 222 along the second direction 30. Thereby, the second housing 221 drives the second accommodating case 222 to move in the second direction 30 relative to the first accommodating case 212 under the driving of the horizontal loading cylinder 410, so as to perform a direct shear test on the rock test block.

The horizontal loading device 400 further includes a horizontal drive 430. Specifically, the horizontal driving member 430 is a cylinder. The horizontal driving member 430 includes a third fixed end 431 and a third actuating end 432. The third fixing end 431 is fixed to the base 110. The third actuating end 432 is connected to the second accommodating case 222 and drives the second accommodating case 222 to move in the second direction 30 with respect to the second housing 221. Thus, the second housing 221 and the second receiving case 222 are provided such that the second half case 220 constitutes a drawer type structure.

When the rock test block needs to be clamped on the rock shearing test device 10, the horizontal driving member 430 can be used for driving the second accommodating shell 222 to move relative to the second shell 221 in the direction away from the horizontal loading cylinder 410 until the second accommodating shell 222 slides out of the second shell 221, at this time, the rock test block is placed into the second accommodating shell 222, the first accommodating shell 212 is sleeved at one end, away from the second accommodating shell 222, of the rock test block, then the horizontal driving member 430 is used for enabling the second accommodating shell 222 loaded with the rock test block and the first accommodating shell 212 to move in the direction towards the horizontal loading cylinder 410 until the second accommodating shell 222 and the first accommodating shell 212 move into the second shell 221 and the first shell 222 respectively, and the clamping work of the rock test block can be completed.

Therefore, by arranging the horizontal driving member 430, arranging the first half box 210 as the first housing 211 and the first accommodating shell 212, and arranging the second half box 220 as the second housing 221 and the second accommodating shell 222, the probability of collision and interference between the rock test block and the parts of the rock shear test equipment 10 in the process of clamping the rock shear test equipment 10 can be avoided, and the clamping work of the rock test block on the rock shear test equipment 10 is simpler. Specifically, the second receiving cavity 222 is slidably mounted on the guide rail 130 to improve the smoothness when the second receiving cavity 222 slides out or in relative to the first housing 221.

Referring to fig. 3 again, in the present embodiment, the vertical loading device 300 further includes a ball head assembly 320. The ball head assembly 320 includes a ball socket 321 and a ball head piece 322 disposed on the ball socket 321. The ball cup 321 is mounted to an end of the normal load cell 510 facing the first cartridge half 210. One end of the ball piece 322 far from the ball socket 321 abuts the first cartridge half 210. The ball head piece 322 and the ball head seat 321 are matched with each other, and the automatic adjustment of the parallelism of the stress surface of the ball head piece 322 can be realized, so that the stress uniformity of a rock test block in the direct shear test process is ensured, and the test effect of the direct shear test is greatly improved.

Referring to fig. 2 and 4 again, in the present embodiment, the horizontal loading device 400 further includes a connecting component 420. The connection assembly 420 includes a first fixing member 421 mounted on the second fixing end 411, a second fixing member 422 mounted on the first half cell 210, and a plurality of connection rods 423 disposed at intervals along the first direction 20. When the rock shear test apparatus 10 is positioned on a horizontal plane, a plurality of the connection rods 423 are arranged at intervals in a vertical direction. The first fixing member 421 and the second fixing member 422 are disposed opposite to each other and spaced apart from each other. Two ends of each connecting rod 423 are movably connected to the first fixing member 421 and the second fixing member 422, respectively.

The plurality of connecting rods 423, the first fixing member 421 and the second fixing member 422 cooperate with each other to form a multi-link mechanism. During the shear test, the first fixing member 421 connected to the horizontal loading cylinder 410 can move only in the first direction 20 and does not deflect, so that the second fixing member 422 constituting the multi-link mechanism does not deflect. Therefore, in the direct shear test process, even if the upper half part and the lower half part of the rock test block respectively positioned in the first half box 210 and the second half box 220 have the tendency of lateral deflection, the second fixing member 422 only drives the first half box 210 to move along the first direction 20 and the second direction 30 relative to the second half box 220, so that the situation of lateral deflection cannot occur, and the accuracy of the test result is further improved.

In this embodiment, the test assembly 500 further includes a tangential load cell 520. The tangential load sensor 520 is mounted to the second actuating end 412 and is used to measure the tangential stress value of the rock test block structural surface. During the direct shear test, when the horizontal loading cylinder 410 drives the second half-box 220 to move along the second direction 30, the tangential load sensor 520 is used to measure the tangential stress value of the rock test block structural surface, so as to facilitate the subsequent acquisition of the stress parameter of the rock test block structural surface of the direct shear test by using the measured tangential stress value and the normal stress value.

Further, in the present embodiment, the testing assembly 500 further includes a normal displacement sensor 530 and a horizontal displacement sensor 540. The normal displacement sensor 530 is mounted on the first half-box 210, and is used for measuring the normal displacement value of the first half-box 210 during the direct shear test. A horizontal displacement sensor 540 is mounted on the second cassette half 220 for measuring the tangential displacement value of the second cassette half 220 during the direct shear test.

During the direct shear test, in the process that the horizontal loading cylinder 410 drives the second half box 220 to move along the second direction 30, the normal displacement sensor 530 and the horizontal displacement sensor 540 are used for measuring the normal displacement value and the tangential displacement value of the rock test block structural surface respectively, so that the displacement parameters of the rock test block structural surface can be obtained by using the measured normal displacement value and the measured tangential displacement value conveniently.

Specifically, one end of the normal displacement sensor 530 is mounted on the first half-case 210, and the contact at the other end is in contact with the second half-case 220; one end of the horizontal displacement sensor 540 is mounted on the second half casing 220, and the other end of the contact is in contact with the bracket 120.

Referring to fig. 1 again, in the present embodiment, a hydraulic controller 600 is further included. The hydraulic controller 600 is electrically connected to the normal loading cylinder 310 and the tangential loading cylinder, respectively, and controls the first action end 312 and the second action end 412 to operate according to a preset command. Specifically, in the direct shear test process, the hydraulic controller 600 controls the first half box 210 to move along the first direction 20 and the second half box 220 to slide along the second direction 30 according to a preset command, so as to automatically control the movement of the first half box 210 and the second half box 220. Accordingly, the provision of the hydraulic controller 600 effectively improves the automation of the rock shear test apparatus 10 and improves the accuracy of operation of the rock shear test apparatus 10.

Preferably, the rock shear test apparatus 10 further comprises a digital controller 700. The digital controller 700 is in communication connection with any one of the normal load sensors 510, the tangential load sensor 520, the normal displacement sensor 530 and the horizontal displacement sensor 540, and calculates the stress parameters and displacement parameters of the rock test block according to the normal stress value, the tangential stress value, the normal displacement value and the tangential displacement value.

Thus, the digital controller 700 may enable automatic switching of the plurality of normal load sensors 510. During the direct shear test, the normal load sensor 510, the tangential load sensor 520, the normal displacement sensor 530 and the horizontal displacement sensor 540 respectively measure a normal stress value, a tangential stress value, a normal displacement value and a tangential displacement value of the rock test block structural surface, convert the normal stress value, the tangential stress value, the normal displacement value and the tangential displacement value into electric signals and transmit the electric signals to the digital controller 700, and the digital controller 700 calculates stress parameters and displacement parameters of the rock test block structural surface according to the electric signals. Therefore, the digital controller 700 greatly improves the automatic calculation of the test result in the direct shear test, and is beneficial to improving the working efficiency of the direct shear test.

Further, in this embodiment, the rock shear test apparatus 10 further includes an upper computer 800. The host computer 800 includes an input device (not shown) and a display 810. The input unit is electrically connected with the digital controller 700, the input unit is used for receiving the interactive operation and converting the interactive operation into a preset instruction, and the digital controller 700 is electrically connected with the hydraulic controller 600, so that the hydraulic controller 600 controls the normal loading cylinder 310 and the tangential loading cylinder to operate according to the preset instruction. Specifically, the input device may be an input device such as a touch screen, an input keyboard, an input mouse, and a control knob. The input device is an input device used by the upper computer 800 for receiving interactive operation input by an operator and generating an operation instruction. When the input device receives the operation of the operator such as rotation, pressing, or motor, the first operation end 312 and the second operation end 412 move along the first direction 20 and the second direction 30, respectively. From this, the setting of input device for rock shear test equipment 10 shell realizes the real-time interaction with operating personnel, thereby makes rock shear test equipment 10 stronger with operating personnel's interactivity.

The display 810 is electrically connected to the digital controller 700 to display the stress parameter information and the displacement parameter information. Therefore, an operator can more intuitively read or observe the change conditions of the stress parameters and the displacement parameters in the whole direct shear test process in real time, so that data support is provided for research on the stress, deformation and damage mechanisms of the rock test block structural surface under high pressure, and the rock shear test equipment 10 is more convenient to use due to the arrangement of the display 810.

Above-mentioned shear test equipment, during the use, can adjust shear box 200 accommodation space's volume according to the size of rock test block for the rock test block of different size specifications all is comparatively firm in the clamping of shear box 200, and is comparatively steady in order to guarantee the direct shear test process, has improved the accuracy of direct shear test result effectively. Furthermore, the normal load sensors 510 can be freely switched, and one normal load sensor 510 with a measuring range matched with the rock test block to be tested can be selected before the direct shear test, so that the rock test block structural surface can be accurately measured in the direct shear test process, and the accuracy of the direct shear test result is further improved. Therefore, the rock shearing test equipment 10 can be used for carrying out direct shearing tests on rock test blocks with different sizes and specifications, and the accuracy of direct shearing test results is higher.

Referring to fig. 10, the present invention also provides a shear test testing method for a rock test block, which includes steps S001 to S004.

And S001, placing the rock test block in a shearing box. The shearing box comprises a first half box and a second half box which are oppositely arranged, and the connecting line direction of the first half box and the second half box is a first direction.

Specifically, the first half box and the second half box are opposite and are arranged in a stacked mode to form an accommodating space for accommodating the rock test block. When the shear box is in a horizontal position, the first direction is a vertical direction.

And S002, applying an initial normal load to the first half box by using a normal loading oil cylinder so as to enable the first half box to move along the first direction until the structural surface of the rock test block is in a preset state.

Specifically, the normal loading oil cylinder drives the first half box to move along the different directions until the rock test block is clamped in the first half box and the second half box.

And S003, applying an initial normal load to the first half box by using a normal loading oil cylinder, and simultaneously driving the second half box to move along a second direction perpendicular to the first direction by using a horizontal loading oil cylinder until the displacement value of the second half box reaches a preset horizontal displacement value. The normal load value is according to the equation: f_n ^t+1＝F_n ^t+Δh_t+1And K is obtained by calculation,

wherein the content of the first and second substances,

k is a normal stiffness coefficient, t is a time value, and the increment of the normal displacement in the unit sampling interval from the real-time measurement of the normal displacement sensor LVDT from the time t to the time t +1 is delta h_t+1。

When the shearing box is positioned on the horizontal plane, the second direction is the horizontal direction, so the horizontal loading oil cylinder drives the second half box to move along the horizontal direction, and the shearing effect on the rock test block in the shearing box is realized.

In the direct shear test process, the structural surface of the rock test block is easy to warp locally in the shearing process to cause severe normal deformation fluctuation, so that the stability of the direct shear test process is influenced. During the whole direct shear test process, the equation F is utilized_n ^t+1＝F_n ^t+Δh_t+1K, calculating to obtain a normal load value, and then controlling a normal loading oil cylinder to apply a normal load to the first half box so as to improve the stability of the direct shear test process.

And step S004, measuring the normal load value, the shearing load value, the normal displacement value and the shearing displacement value of the rock test block structural surface in real time by using the normal load sensor, the tangential load sensor, the normal displacement sensor and the horizontal displacement sensor, and obtaining the stress parameter and the displacement parameter required by the test according to the normal load value, the tangential load value, the normal displacement value and the shearing displacement value.

Specifically, the normal load sensor, the tangential load sensor, the normal displacement sensor and the horizontal displacement sensor measure the normal load value, the shear load value, the normal displacement value and the shear displacement value of the rock test block structural surface in real time in the execution process of the step S003, and after the execution of the step S003 is finished, the stress parameter and the displacement parameter required by the test are obtained according to the normal load value, the tangential load value, the normal displacement value and the tangential displacement value.

The normal load value in step S003 is according to equation F_n ^t+1＝F_n ^t+Δh_t+1K is obtained through calculation, so that the normal stiffness can not fluctuate dramatically when the normal loading oil cylinder applies the normal load to the first half box, the direct shear test process is stable, the accuracy of load measurement and displacement measurement data in the direct shear test process is further ensured, and the accuracy of the direct shear test result is effectively improved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A rock shear test apparatus, comprising:

2. The rock shear test equipment of claim 1, wherein the support comprises a connecting seat and at least three parallel and spaced columns, the at least three columns are arranged on one side of the connecting seat facing the base along the circumferential direction of the connecting seat, one end of each column far away from the connecting seat is fixedly connected with the base, and the first fixing end is fixedly connected with the connecting seat.

3. The rock shear test apparatus of claim 1, wherein the main frame further comprises a rail mounted on the base and extending in the second direction, the second half-box being slidably mounted on the rail;

4. The rock shear test apparatus of claim 1, wherein the first half-boxes are plural, and the plural first half-boxes are sequentially nestable from inside to outside, and the opening directions of the plural first half-boxes are consistent, the second half-boxes are plural, and the plural second half-boxes are sequentially nestable from inside to outside, and the opening directions of the plural second half-boxes are consistent, the plural first half-boxes and the plural second half-boxes are respectively in one-to-one correspondence, and each of the one ends of the first half-boxes and the one ends of the second half-boxes are opposite to each other.

5. The rock shear test apparatus of claim 4, wherein the plurality of first half-boxes comprise a first housing and a first receiving shell nestable within the first housing, the first actuating end being connected to the first housing;

6. The rock shear test apparatus of claim 1, wherein the horizontal loading device further comprises a connecting assembly, the connecting assembly includes a first fixing member mounted on the second fixing end, a second fixing member mounted on the first half box, and a plurality of connecting rods spaced along the first direction, the first fixing member and the second fixing member are disposed opposite to each other and spaced apart from each other, and two ends of each connecting rod are movably connected to the first fixing member and the second fixing member, respectively.

7. The rock shear test apparatus of claim 1, wherein the test assembly further comprises a tangential load cell mounted to the second action end and configured to measure a horizontal stress value of the rock test block.

8. The rock shear test apparatus of claim 7, wherein the test assembly further comprises a normal displacement sensor mounted on the first half-box for measuring a normal displacement value of the first half-box during a direct shear test, and a horizontal displacement sensor mounted on the second half-box for measuring a tangential displacement value of the second half-box during a direct shear test.

9. The rock shear test apparatus of claim 8, further comprising a hydraulic controller electrically connected to the normal loading cylinder and the tangential loading cylinder, respectively, and controlling the first actuation end and the second actuation end to operate according to a preset instruction;

10. A direct shear test testing method for a rock test block is characterized by comprising the following steps:

wherein the content of the first and second substances,