WO2021056321A1

WO2021056321A1 - High-rigidity and multi-axis high stress loading frame apparatus

Info

Publication number: WO2021056321A1
Application number: PCT/CN2019/108105
Authority: WO
Inventors: 赵骏; 冯夏庭; 杨成祥; 田军
Original assignee: 东北大学
Priority date: 2019-09-24
Filing date: 2019-09-26
Publication date: 2021-04-01
Also published as: CN110658084A; CN110658084B

Abstract

A high-rigidity and multi-axis high stress loading frame apparatus, comprising a vertical frame unit and a horizontal frame unit. The vertical frame unit comprises a ring frame (11) and a ring frame supporting platform (15); the upper surface of the ring frame supporting platform (15) is screwed with the ring frame (11) by means of bolts; the horizontal frame unit comprises a lateral auxiliary push-pull frame (12), a horizontal supporting platform (14), and guide rails (13); the horizontal supporting platform (14) is located at the rear end of the ring frame supporting platform (15); the guide rails (13) are symmetrically mounted on the horizontal supporting platform (14); the guide rails (13) are arranged along the length direction of the horizontal supporting platform (14); the guide rails (13) extend to the ring frame (11), and the tail ends of the guide rails extend out of the ring frame (11); the lateral auxiliary push-pull frame (12) is slidably mounted by means of a sliding block and the guide rails (13). By means of the coordination of different hydraulic cylinders during test, a true triaxial hard rock shear test machine using the high-rigidity and multi-axis high stress loading frame apparatus may achieve a shear test under the condition that all the end surfaces of a rock sample (19) are stressed, and the true triaxial stress state of an on-site rock mass is satisfied.

Description

High-rigidity multiaxial high-stress loading frame device

Technical field

The invention relates to the technical field of rock indoor loading tests, in particular to a high-rigidity multiaxial high-stress loading frame device.

Background technique

With the excavation of underground mining and underground rock mass engineering, the stability of deep-buried hard rock engineering has become more and more important. Generally speaking, rocks are controlled by true three-dimensional stress, and for hard rocks with weak structural surfaces, engineering disasters of varying degrees are prone to occur under the action of shear forces. Therefore, carrying out the shear test under true triaxial stress is of great significance to the study of underground engineering disasters.

The loading frame structure adopted by the existing shear testing machine can only perform a simple direct shear test during the test, that is, the frame provides normal stress in the vertical direction and shear stress in the horizontal direction. The direct shear test assumes that the lateral stress has no effect on the deformation and failure of the rock, but in the real situation, the rock is limited by the surrounding rock mass and there is a certain lateral stress. Moreover, due to space constraints, in the shear direction, half of the section of the rock sample is always unstressed. In real underground rock engineering, all parts of the rock are under stress. Only when all sections of the rock in the shear test are loaded with the same true three-dimensional stress as the on-site rock mass, can we understand the shear failure mechanism of the rock under high stress to the greatest extent through the laboratory test.

In addition, the existing shear test machines all use column-type or tie-rod-type frames, and these frame structures generally have low rigidity. For hard rock shear testing machines with tonnage requirements up to 200 tons or more, the loading frame accumulates a large amount of strain energy during the shear test before the rock sample is damaged. When the rock is locally damaged, the loading frame with lower rigidity The accumulated elastic strain energy is released instantaneously, distorting the failure characteristics of the rock behind the peak.

Summary of the invention

technical problem

The solution to the problem

Technical solutions

In view of the problems existing in the prior art, the present invention provides a high-rigidity multiaxial high-stress loading frame device, which can apply high stress up to 1200Mpa. The hard rock true triaxial shear test machine using the loading frame structure can realize rock The specimen is subjected to shear test under true triaxial stress conditions, and a new integrated frame structure is adopted to increase the stiffness of the loading frame to meet the requirements of hard rock shear test under high-pressure true triaxial conditions.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A high-rigidity multi-axis high-stress loading frame device includes a vertical frame unit and a horizontal frame unit; the vertical frame unit includes a ring frame and a ring frame support platform. The upper surface of the ring frame support platform is bolted to the ring frame The horizontal frame unit includes a lateral auxiliary push-pull frame, a horizontal support platform and a guide rail, the horizontal support platform is located at the rear end of the ring frame support platform, the horizontal support platform is symmetrically installed with guide rails, and the guide rails are arranged along the length of the horizontal support platform , The guide rail extends to the ring frame, and the end extends out of the ring frame, and the lateral auxiliary push-pull frame is slidably installed with the horizontal support platform through the sliding block and the guide rail.

The ring frame has a circular ring shape, and the ring frame is evenly provided with four through holes along the circumferential direction, which are the left through hole of the ring frame, the upper through hole of the ring frame, the right through hole of the ring frame and the lower through hole of the ring frame. The line connecting the center of the upper through hole and the lower through hole of the ring frame is perpendicular to the horizontal plane, the line connecting the center of the left through hole of the ring frame and the center of the right through hole of the ring frame is parallel to the horizontal plane, and the upper through hole of the ring frame is provided with an upper normal loading through a screw In the cylinder, the lower through hole of the ring frame is provided with a lower normal loading cylinder through screws. The end cover of the lower normal loading cylinder and the end cover of the upper normal loading cylinder are both equipped with displacement sensors. The left through hole of the ring frame passes through the screws. A combined tangential loading oil cylinder at the left end is provided, and a combined tangential loading oil cylinder at the right end is provided in the right through hole of the ring frame through a screw.

The lateral auxiliary push-pull frame is a columnar structure with an I-shaped cross section. The lateral auxiliary push-pull frame rectangular through holes, the upper through holes of the lateral auxiliary push-pull frame and the lateral auxiliary push-pull frame are respectively opened in the circumferential direction of the lateral push-pull frame The lower through holes are respectively provided with the front through holes of the lateral auxiliary push-pull frame and the rear through holes of the lateral auxiliary push-pull frame in the axial direction of the lateral push-pull frame. The center line and the lateral auxiliary holes of the rectangular through hole of the lateral auxiliary push-pull frame The line between the through hole on the push-pull frame and the center of the through hole of the lateral auxiliary push-pull frame is vertically arranged, and the line between the through hole on the lateral auxiliary push-pull frame and the center of the lower through hole of the lateral auxiliary push-pull frame and the side The line between the front through hole of the auxiliary push-pull frame and the center of the rear through hole of the lateral auxiliary push-pull frame is set vertically. The front-end side loading cylinder is provided through the screw in the front through hole of the lateral auxiliary push-pull frame, and the auxiliary push-pull is laterally. A rear-end lateral loading cylinder is provided in the through hole of the frame through screws, and a test box is set on the surface of the rectangular through hole of the lateral auxiliary push-pull frame. A shear box is installed in the test box, and a rock sample is placed in the shear box. .

The left-end combined tangential loading cylinder includes a left tangential upward loading cylinder and a left tangential downward loading cylinder. The left tangential upward loading cylinder is coaxially sleeved in the left tangential downward loading cylinder, and the end of the left tangential upward loading cylinder A displacement sensor is installed on the cover, and the left-cut-down loading oil cylinder is a hollow oil cylinder.

The right-end combined tangential loading cylinder includes a right-cut-up loading cylinder and a right-cut-down loading cylinder. The right-cut-down loading cylinder sleeve is coaxially embedded in the right-cut-up loading cylinder, and the right-cut-down loading cylinder is A displacement sensor is installed on the end cover of the, and the right tangential upward loading cylinder is a hollow cylinder.

The front-end combined lateral loading cylinder includes a front-side upward loading cylinder and a front-side loading cylinder. The front-side down-loading cylinder liner is coaxially embedded in the front-side up-loading cylinder, and the front-side loading cylinder is downwardly loaded. A displacement sensor is installed on the end cover, and the front side is upwardly loaded with a hollow cylinder.

The rear-end combined lateral loading cylinder includes a rear-side upward-loading cylinder and a rear-side downward-loading cylinder. The rear-side down-loading cylinder is coaxially sleeved in the rear-side up-loading cylinder and is loaded at the rear side downward. A displacement sensor is installed on the end cover of the oil cylinder, and the rear-side upward loading oil cylinder is a hollow oil cylinder.

Both the annular frame and the lateral auxiliary push-pull frame are manufactured by integral casting.

The beneficial effects of the invention

Beneficial effect

Compared with the prior art, the present invention adopts the hard rock true triaxial shear test machine with the high rigidity multiaxial high stress loading frame structure of the present invention. The test process realizes all end faces of the rock sample through the cooperation of different hydraulic cylinders. The shear test under uniform stress conditions is more in line with the true triaxial stress state of the rock mass on site. Moreover, the ring frame and the lateral auxiliary push-pull frame of the present invention abandon the low-rigidity tie rod and column frame structure used in the traditional loading frame structure, and are manufactured by the integral casting process. While meeting the requirements of large load output, it also makes the overall rigidity of the equipment It is greatly improved, and it is more helpful to obtain the real deformation and failure characteristics of hard rock.

Brief description of the drawings

Description of the drawings

Figure 1 is a schematic diagram of the high-rigidity multi-axis high-stress loading frame device of the present invention;

2 is a schematic diagram of the ring frame structure of the high-rigidity multi-axis high-stress loading frame device of the present invention;

3 is a schematic diagram of the lateral auxiliary push-pull frame structure of the high-rigidity multi-axis high-stress loading frame device of the present invention;

Figure 4 is a front cross-sectional view of the high-rigidity multiaxial high-stress loading frame device of the present invention;

Figure 5 is a side cross-sectional view of the high-rigidity multiaxial high-stress loading frame device of the present invention;

In the figure, 1-left cut-up loading cylinder, 2-left cut-down loading cylinder, 3-upper normal loading cylinder, 4-right cut-down loading cylinder, 5-right cut-up loading cylinder, 6-down normal Loading cylinder, 7-front loading cylinder downwards, 8-front loading cylinder upwards, 9-rear loading cylinder downwards, 10-rear loading cylinder upwards, 11-ring frame, 12-lateral auxiliary sliding frame, 13-rail, 14-horizontal support platform, 15-ring frame support platform, 16-displacement sensor, 17-test box, 18-shear box, 19-rock specimen, 20-ring frame left through hole, 21-ring Through hole on the frame, 22-right through hole of ring frame, 23-through hole under ring frame, 24-front through hole of lateral auxiliary push-pull frame, 25-through hole of lateral auxiliary push-pull frame, 26-lateral auxiliary push-pull frame The upper through hole, 27-the lower through hole of the lateral auxiliary push-pull frame, 28-the installation platform, 29-the rectangular through hole of the lateral auxiliary push-pull frame.

Invention embodiment

Embodiments of the present invention

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

As shown in Figures 1 to 5, a high-rigidity multiaxial high-stress loading frame device includes a vertical frame unit and a horizontal frame unit; the vertical frame unit includes a ring frame 11 and a ring frame support platform 15, which is supported by the ring frame The upper surface of the platform 15 is bolted to a ring frame 11, and the ring frame support platform 15 is fixedly installed on the ground by bolts; the horizontal frame unit includes a lateral auxiliary push-pull frame 12, a horizontal support platform 14 and a guide rail 13. The horizontal support platform 14 is located at the rear end of the ring frame support platform 15 and is fixedly installed on the ground by bolts. The horizontal support platform 14 is symmetrically installed with guide rails 13 and the guide rails 13 are arranged along the length of the horizontal support platform 14, and the guide rails 13 extend to the ring frame 11 is a platform on the center hole, and the end extends out of the ring frame 11, and the lateral auxiliary push-pull frame 12 is slidably installed with the horizontal support platform 14 through a sliding block and a guide rail 13.

The ring frame 11 has a circular ring shape, and the ring frame 11 is evenly provided with four through holes along the circumferential direction, and the four through holes are counterbores. The large and smaller ends of the counterbore are close to the outside of the ring frame 11. The bottom surface of the large hole end of the counterbore is evenly provided with threaded holes along the circumferential direction. The four through holes are the left through hole 20 of the ring frame, the through hole 21 on the ring frame, the right through hole 22 of the ring frame, and the ring frame. The lower through hole 23, the center line of the upper through hole 21 of the ring frame and the lower through hole 23 of the ring frame is perpendicular to the horizontal plane, the center line of the left through hole 20 of the ring frame and the right through hole 22 of the ring frame is parallel to the horizontal plane, in the inner wall of the ring frame 11 Two installation platforms 28 are processed. The two installation platforms 28 are arranged symmetrically with respect to the center of the lower through hole 23 of the ring frame. The installation platform 28 is mainly used to fix the extension of the mounting rail 13 through which the upper through hole 21 of the ring frame passes The upper normal loading cylinder 3 is installed with the screw and the threaded hole. The lower normal loading cylinder 6 is installed in the lower through hole 23 of the ring frame through the screw and the threaded hole. The end cover of the lower normal loading cylinder 6 and the upper normal A displacement sensor 16 is installed on the end cover of the loading cylinder 3, a left-end combined tangential loading cylinder is installed in the left through hole 20 of the ring frame through a screw and a threaded hole, and the right through hole 22 of the ring frame is installed through a screw and a threaded hole. There is a combined tangential loading cylinder at the right end.

The lateral auxiliary push-pull frame 12 is a columnar structure with an I-shaped cross-section. A rectangular through hole 29 of the lateral auxiliary push-pull frame, a through hole 26 on the lateral auxiliary push-pull frame, and a lateral auxiliary push-pull frame are respectively opened in the circumferential direction of the lateral push-pull frame. The lower through hole 27 of the auxiliary push-pull frame is respectively provided with the front through hole 24 and the rear through hole 25 of the lateral auxiliary push-pull frame in the axial direction of the lateral push-pull frame, and the front through hole 24 and the side of the lateral auxiliary push-pull frame The through hole 25 after the auxiliary push-pull frame is a countersunk hole. The small hole end of the countersunk hole is set close to the outside. The bottom surface of the large hole end of the countersunk hole is evenly provided with threaded holes along the circumferential direction. The line between the center line of the rectangular through hole 29 of the auxiliary push-pull frame and the center of the upper through hole 26 of the lateral auxiliary push-pull frame and the center of the lower through hole 27 of the lateral auxiliary push-pull frame is vertically arranged, the upper through hole of the lateral auxiliary push-pull frame 26 and the line between the center of the lower through hole 27 of the lateral auxiliary push-pull frame and the line between the center of the front through hole 24 of the lateral auxiliary push-pull frame and the center of the rear through hole 25 of the lateral auxiliary push-pull frame. The front through hole 24 of the push-pull frame is equipped with a front-end side loading cylinder through screws and threaded holes. In the lateral auxiliary push-pull frame, the rear through hole 25 is equipped with a rear-end side loading cylinder through screws and threaded holes. The surface of the rectangular through hole 29 of the auxiliary push-pull frame is provided with a test box 17, a shear box 18 is installed in the test box 17, and a rock sample 19 is placed in the shear box 18. By setting the upper through hole 26 of the lateral auxiliary push-pull frame, the lower through hole 27 of the lateral auxiliary push-pull frame, and the rectangular through hole 29 of the lateral auxiliary push-pull frame, the left end combined tangential loading cylinder, the right end combined tangential loading cylinder, and the upper normal loading The oil cylinder 3 and the lower normal oil cylinder can directly apply a load to the rock sample 19.

The left-end combined tangential loading cylinder includes a left tangential upward loading cylinder 1, a left tangential downward loading cylinder 2. The left tangential upward loading cylinder 1 is coaxially sleeved in the left tangential downward loading cylinder 2, and is positioned on the left A displacement sensor 16 is installed on the end cover of the upward loading cylinder 1, and the left-cut downward loading cylinder 2 is a hollow cylinder.

The right-end combined tangential loading cylinder includes a right-cut-up loading cylinder 5, a right-cut-down

loading cylinder

4, and 4 sets of the right-cut-down loading cylinder are coaxially embedded in the right-cut-up loading cylinder 5. A displacement sensor 16 is installed on the end cover of the downward loading cylinder 4, and the right tangential upward loading cylinder 5 is a hollow cylinder.

The front-end combined lateral loading cylinder includes a front-side up loading cylinder 8 and a front-side down loading cylinder 7. The front-side down loading cylinder 7 is coaxially embedded in the front-side up loading cylinder 8 and is located on the front side. A displacement sensor 16 is installed on the end cover of the downward loading cylinder 7, and the front side upward loading cylinder 8 is a hollow cylinder.

The rear-end combined lateral loading cylinder includes a rear-side upward-loading oil cylinder 10 and a rear-side downward-loading cylinder 9. The rear-side down-loading cylinder 9 is coaxially sleeved and embedded in the rear-side up-loading cylinder 10, and A displacement sensor 16 is installed on the end cover of the rear-side downward loading cylinder 9, and the rear-side upward loading cylinder 10 is a hollow cylinder. The use of nested loading cylinders saves the overall space of the frame, and ensures that the rigid pressure blocks do not interfere with each other when the rock sample 19 is loaded up and down, and the rigidity of the overall frame is improved.

The annular frame 11 and the lateral auxiliary push-pull frame 12 are both manufactured by integral casting. The use of integral forging technology avoids the large deformation of the assembly under pressure after the frame is assembled, thereby reducing the frame rigidity.

A stress loading method for a high-rigidity multi-axis high-stress loading frame device adopts a high-rigidity multi-axis high-stress loading frame device and includes the following steps:

Step 1. Before installing the rock sample 19, the lateral auxiliary push-pull frame 12 is located at the foremost end of the guide rail 13, and extends out of the ring frame 11 to set the rock sample 19 into the shear box 18 of the lateral auxiliary push-pull frame 12. Then push the lateral auxiliary push-pull frame 12 equipped with the rock sample 19 into the center position of the ring frame 11;

Step 2. Apply normal pre-tightening force, firstly pre-stress the normal direction, and control the upward movement of the piston in the normal load cylinder 6 to move the rock sample 19 in the test box 17 to the center of the test box 17 Position; then control the piston of the upper normal loading cylinder 3 to move downwards to make the rock sample 19 normal to produce a certain pre-tightening force;

Step 3: Apply lateral pretension, and control the pistons of the front combined lateral loading cylinder and the rear combined lateral loading cylinder to move synchronously so that the lateral cross-section of the rock sample obtains equal pretension;

Step 4. Test the loading process. Firstly, the pistons in the upper normal loading cylinder 3 and the lower normal loading cylinder 6 are synchronously controlled to load to the minimum principal stress target value with equal force values at the same speed; then the front side upward loading cylinder is controlled synchronously 8. The pistons of the front-side downward-loading cylinder 7, the rear-side upward-loading cylinder 10, and the rear-side downward-loading cylinder 9 are loaded with equal force values and constant speed to the target value of the intermediate principal stress; the final shear force is also loaded It is carried out in two steps, the left tangential upward loading cylinder 1, the left tangential downward loading cylinder 2, the right tangential upward loading cylinder 5 and the right tangential downward loading cylinder 4, the pistons are loaded to the intermediate principal stress target at equal force values at a constant speed Then keep the load of the left tangential downward loading cylinder 2, right tangential upward loading cylinder 5 unchanged, while the left tangential upward loading cylinder 1, right tangential downward loading cylinder 4 always control the forward movement of the piston by force control or deformation control. During the movement process, the force values of the left tangential upward loading cylinder 1 and the right tangential downward loading cylinder 4 are always the same until the rock sample 19 undergoes shear failure, and the test ends.

Claims

A high-rigidity multi-axis high-stress loading frame device is characterized in that it comprises a vertical frame unit and a horizontal frame unit; the vertical frame unit comprises a ring frame and a ring frame support platform. The upper surface of the ring frame support platform is bolted and screwed. A ring frame is connected; the horizontal frame unit includes a lateral auxiliary push-pull frame, a horizontal support platform and a guide rail. The horizontal support platform is located at the rear end of the ring frame support platform. The horizontal support platform is symmetrically installed with guide rails, and the guide rails are supported horizontally The platform is arranged in the longitudinal direction, the guide rail extends to the ring frame, and the end extends out of the ring frame, and the lateral auxiliary push-pull frame is slidably installed with the horizontal support platform through the slider and the guide rail.
The high-rigidity, multi-axis, high-stress loading frame device according to claim 1, wherein the ring-shaped frame has a circular ring shape, and the ring-shaped frame is evenly provided with four through holes along the circumferential direction, each of which is the left side of the ring-shaped frame. Through holes, through holes on the ring frame, right through holes on the ring frame, and through holes on the bottom of the ring frame, the center line of the through holes on the ring frame and the lower through holes of the ring frame is perpendicular to the horizontal plane, the left through hole of the ring frame and the right through hole of the ring frame The center line is parallel to the horizontal plane, the upper through hole of the ring frame is provided with an upper normal loading cylinder through a screw, and the lower through hole of the ring frame is provided with a lower normal loading cylinder through a screw, and the lower normal loading cylinder and the upper normal Displacement sensors are installed on the end covers of the loading cylinders. The left through hole of the ring frame is provided with a left end combined tangential loading cylinder through a screw, and the right through hole of the ring frame is provided with a right end combined tangential loading cylinder through a screw.
The high-rigidity multiaxial high-stress loading frame device according to claim 1, characterized in that: the lateral auxiliary push-pull frame is a columnar structure with an I-shaped cross section, and the lateral push-pull frame is respectively provided in the circumferential direction The rectangular through hole of the lateral auxiliary push-pull frame, the upper through hole of the lateral auxiliary push-pull frame, and the lower through hole of the lateral auxiliary push-pull frame. The lateral auxiliary push-pull frame front through holes and the lateral auxiliary are respectively opened in the axial direction of the lateral push-pull frame. The rear through hole of the push-pull frame, the line between the center line of the rectangular through hole of the lateral auxiliary push-pull frame and the through hole on the lateral auxiliary push-pull frame and the center of the lower through hole of the lateral auxiliary push-pull frame is vertically arranged, and the lateral auxiliary push-pull frame The line between the through hole of the auxiliary sliding frame and the center of the lower through hole of the lateral auxiliary sliding frame and the line between the front through hole of the lateral auxiliary sliding frame and the center of the rear through hole of the lateral auxiliary sliding frame are arranged vertically. The front through hole of the auxiliary push-pull frame is provided with a front-end combined side loading cylinder through screws, and the rear-end combined side loading cylinder is provided through a screw in the rear through hole of the auxiliary push-pull frame, and the rectangular through hole of the lateral auxiliary push-pull frame A test box is installed on the surface of the test box, a shear box is installed in the test box, and a rock sample is placed in the shear box.
The high-rigidity multi-axis high-stress loading frame device according to claim 2, wherein the left-end combined tangential loading cylinder includes a left tangential upward loading cylinder, a left tangential downward loading cylinder, and the left tangential upward loading cylinder The loading cylinder coaxial sleeve is embedded in the left tangential downward loading cylinder, a displacement sensor is installed on the end cover of the left tangential upward loading cylinder, and the left tangential downward loading cylinder is a hollow cylinder.
The high-rigidity multi-axis high-stress loading frame device according to claim 2, wherein the right-end combined tangential loading cylinder includes a right tangential upward loading cylinder, a right tangential downward loading cylinder, and the right tangential The lower loading cylinder sleeve is coaxially embedded in the right tangential upward loading cylinder, and a displacement sensor is installed on the end cover of the right tangential downward loading cylinder, and the right tangential upward loading cylinder is a hollow cylinder.
The high-rigidity multi-axis high-stress loading frame device according to claim 3, wherein the front-end combined lateral loading cylinder includes a front-side upward loading cylinder, a front-side downward loading cylinder, and the front side The lower loading cylinder sleeve is coaxially embedded in the front side upward loading cylinder, and a displacement sensor is installed on the end cover of the front side downward loading cylinder, and the front side upward loading cylinder is a hollow cylinder.
The high-rigidity multi-axis and high-stress loading frame device according to claim 3, wherein the rear-end combined lateral loading cylinder includes a rear-side upward loading cylinder and a rear-side down loading cylinder. The coaxial sleeve of the downward loading oil cylinder is embedded in the rear side upward loading oil cylinder, and a displacement sensor is installed on the end cover of the rear side downward loading oil cylinder, and the rear side upward loading oil cylinder is a hollow oil cylinder.
The high-rigidity multi-axis high-stress loading frame device according to claim 1, wherein the annular frame and the lateral auxiliary push-pull frame are both manufactured by integral casting.