CN112665984A

CN112665984A - Wedge-shaped clamp for testing uniaxial tensile property of rock

Info

Publication number: CN112665984A
Application number: CN202110023751.5A
Authority: CN
Inventors: 项华松; 马冬冬; 张蓉蓉; 潘长春; 黄坤; 施宇航
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2021-01-08
Filing date: 2021-01-08
Publication date: 2021-04-16

Abstract

The invention discloses a wedge-shaped clamp for testing uniaxial tensile property of a rock, which consists of a clamp box, a rock standard test piece, clamping pieces, springs, connecting rods, a synchronous disc, a middle shaft and a back disc, wherein the four clamping pieces are symmetrically distributed in the clamp box along the circumferential direction, spherical sliding grooves for the clamping pieces to be arranged are arranged in the clamp box, spherical convex components are arranged on the outer sides of the clamping pieces, the spherical sliding grooves are used for the clamping pieces to slide, each clamping piece is connected with the corresponding connecting rod, the connecting rods are connected with the synchronous disc through limiting holes arranged in the clamp box, the springs are arranged on the connecting rods and the clamping pieces at the contact ends, and a round hole is formed in the center of the synchronous disc for the middle shaft to pass.

Description

Wedge-shaped clamp for testing uniaxial tensile property of rock

Technical Field

The invention relates to a wedge-shaped clamp for testing uniaxial tensile property of rock.

Background

The rock is easy to pull and not easy to press in engineering, so that the problem of damage caused by tensile stress is more and more increased, at present, indirect methods such as Brazilian split test and bending test are generally adopted for testing the tensile strength of the rock, wherein the Brazilian split test is the most common method, and is an indirect tensile test method, and the test result of the rock is not in a real tensile stress state, so that errors exist. The existing rock axial direct tension device uses a clamp with two forms: adhesive and friction. Wherein the bonding mode causes the eccentricity of the stretching process due to the non-uniformity of bonding in the manual bonding operation process; the friction type is easy to cause stress concentration, and a test piece is not stretched and damaged in advance, so that the existing direct stretching has a plurality of problems and cannot obtain real uniaxial tensile property of the rock.

Therefore, reducing stress concentration and tension eccentricity in uniaxial tension test of rock is a problem to be solved urgently.

Disclosure of Invention

The invention provides a wedge-shaped clamp for testing uniaxial tensile property of a rock, which can overcome the technical problems of stress concentration and tensile eccentricity of a rock tensile strength testing device in the prior art in the process of testing.

In order to achieve the purpose, the invention adopts the following technical scheme:

a wedge-shaped clamp for testing the uniaxial tensile property of rock is composed of a clamping box, a rock standard test piece, a clamping piece, a spring, a connecting rod, a synchronous disk, a middle shaft and a back disk. The clamping device comprises a clamping box, wherein four clamping pieces are symmetrically distributed in the clamping box along the circumferential direction, spherical sliding grooves for the clamping pieces to be arranged are formed in the clamping box, spherical convex components are arranged on the outer sides of the clamping pieces, the spherical sliding grooves are used for the clamping pieces to slide, each clamping piece is connected with a corresponding connecting rod, the connecting rods are connected with a synchronous disc through limiting holes formed in the clamping box, springs are arranged at the contact ends of the connecting rods and the clamping pieces, a round hole is formed in the center of the synchronous disc and used for a middle.

In the clamp, the clamp box, the middle shaft and the rear disc are formed by pouring at one time.

In the clamp, the inner wall of the clamp box is provided with four spherical sliding grooves which are symmetrically distributed along the circumferential direction.

In the clamp, the clamping piece is an arc-shaped wedge-shaped clamping piece.

In the clamp, the outer side surfaces of the clamping pieces are provided with spherical convex components which are used for sliding in the spherical sliding grooves.

In the clamp, the bottom end of the clamp box is provided with limiting holes symmetrically distributed along the circle center, and the limiting holes are used for connecting the clamping piece and the synchronous disc through the connecting rod.

In the clamp, the synchronous disc, the connecting rod, the middle shaft and the rear disc are all cylinders.

In the above clamp, the spring is a compression spring.

Compared with the prior art, the invention has the beneficial effects that:

firstly, the spherical convex components on the outer sides of the clamping pieces can slide in the spherical sliding grooves in the clamping box, so that the clamping pieces can only move axially in the tensile test process, connecting rods are arranged at the end parts of the four clamping pieces, the connecting rods penetrate through the limiting holes of the outer cylinder and are fixed on the synchronous disc, each clamping piece can be ensured to move synchronously along the axial direction in the tensile test process again, and the non-eccentricity in the tensile test process is ensured;

the four clamping pieces are symmetrically distributed in the clamping box along the circumferential direction, the clamping pieces can slide in the spherical sliding groove in the clamping box, and the adjacent clamping pieces form axial holes and are independent from each other, so that the clamping pieces can radially contract, and a rock test piece can conveniently enter and clamp the rock test piece;

the wedge-shaped self-locking principle is applied, so that in the stretching process, the friction force between the clamping piece and the rock test piece is increased along with the increase of the relative displacement between the clamping piece and the clamping box, the test piece can be simply and quickly clamped by the clamp without bonding, the bonding eccentricity is avoided, the stress area is large, and the stress concentration phenomenon is effectively reduced;

and fourthly, by utilizing the spring, a clamping force can be provided before stretching, so that the rock standard test piece can be fixed conveniently.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a wedge-shaped clamp for testing uniaxial tensile property of rock according to the invention;

FIG. 2 is a sectional view taken along line A-A of the schematic structural diagram;

FIG. 3 is a sectional view taken along line B-B of the schematic structural diagram;

FIG. 4 is a cross-sectional view taken along line C-C of the schematic structure;

the reference numbers in the figures illustrate: 1-clamping box, 2-rock standard test piece, 3-clamping piece, 4-spring, 5-connecting rod, 6-synchronous disk, 7-middle shaft, 8-rear disk, 9-spherical chute, 10-spherical convex component and 11-limiting hole

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b):

fig. 1-4 show a wedge-shaped clamp for testing the single-axis tensile property of rock, which is composed of a clamp box (1), a rock standard test piece (2), a clamping piece (3), a spring (4), a connecting rod (5), a synchronous disc (6), a middle shaft (7) and a rear disc (8). Wherein press from both sides box (1), axis (7), back plate (6) are once only pour and form, press from both sides four clamping pieces (3) of hoop symmetric distribution in the box (1), it has spherical spout (9) that supply clamping piece (3) to settle to press from both sides inside the box (1), the clamping piece (3) outside is provided with spherical protruding component (10), spherical spout (9) supply clamping piece (1) to slide, each clamping piece (1) all links to each other with connecting rod (5) that correspond, connecting rod (5) link to each other with synchronous disc (6) through setting up spacing hole (11) in pressing from both sides box (1), connecting rod (5) and clamping piece (3) contact tip set up spring (4), synchronous disc (6) center is equipped with the round hole and supplies axis (7) to pass, axis (7) link to each other with back plate (8).

The test procedure was as follows:

firstly, preparing a rock standard test piece (2) to be subjected to a tensile test;

secondly, two ends of the rock standard test piece (2) are respectively plugged into the bottom of the clamp;

thirdly, fixing the rear disc (8) on a tension servo;

fourthly, carrying out a uniaxial tensile test;

fifthly, dismounting the clamp;

and sixthly, moving the synchronous disc (6) to the direction far away from the rock standard test piece (2), and taking out the rock test piece which is damaged by pulling.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The utility model provides a wedge anchor clamps for testing rock unipolar tensile properties, includes clamp box (1), rock standard test piece (2), clamping piece (3), spring (4), connecting rod (5), synchronization disc (6), axis (7), back plate (8), its characterized in that: four clamping pieces (3) are symmetrically distributed in the clamping box (1) along the circumferential direction, spherical sliding grooves (9) for the clamping pieces (3) to be arranged are formed in the clamping box (1), spherical convex components (10) are arranged on the outer sides of the clamping pieces (3), the spherical sliding grooves (9) enable the clamping pieces (1) to slide, each clamping piece (1) is connected with a corresponding connecting rod (5), the connecting rods (5) are connected with a synchronous disc (6) through limiting holes (11) formed in the clamping box (1), springs (4) are arranged at contact ends of the connecting rods (5) and the clamping pieces (3), a round hole is formed in the center of the synchronous disc (6) and is used for a middle shaft (7) to penetrate, and the middle shaft (7) is connected with a rear disc (8.

2. The wedge-shaped clamp for testing uniaxial tensile property of rock according to claim 1, wherein: the connecting rod (5), the middle shaft (7) and the rear disc (8) are all cylinders.