CN106289996A - A kind of device carrying out true and false triaxial test - Google Patents

Abstract

The invention discloses a kind of device carrying out true and false triaxial test.It includes σ 1 direction loading system, σ 2 direction loading system, σ 3 direction loading system；When doing true triaxial test, σ 2 direction loading system also includes horizontal pressure head；Described horizontal pressure head is cuboid, and identical with described sample with the cross section of described sample contacts；Described seaming chuck, the bottom shape of described push-down head are square and identical with described sample bed-plate dimension；When rehearsing triaxial test, described seaming chuck, the cross section of described push-down head are circle and identical with described sample bed-plate dimension, and described left horizontal axostylus axostyle, described right horizontal axostylus axostyle respectively with described confined pressure room sealing engagement.Overcome prior art must with false Triaxial tester rehearse triaxial test, make true triaxial test of actual triaxial testing apparatus, the shortcoming that cost is high；There is simple in construction, easily operation, low cost, the advantage that can carry out true and false triaxial test.

Description

A device capable of performing true and false triaxial tests

technical field

The invention relates to the field of rock and soil detection in geotechnical engineering technology, more specifically a device capable of performing true and false triaxial tests.

Background technique

According to the principle of mechanical test, assuming that a rock mass maintains a balanced state, there must be three kinds of stress acting on the mutually perpendicular planes at a certain point (as shown in Figure 3). Forces are called major principal stress σ1, intermediate principal stress σ2, and minor principal stress σ3; the acting surfaces perpendicular to the three principal stresses are respectively called major principal stress surface, intermediate principal stress surface and minor principal stress surface; many engineering problems For example, when the length of a deeply buried horizontal roadway is large, it can be treated as a plane strain problem, that is, only σ1 and σ3 are considered; when considering the shallow ground stress, it is generally considered that the ground stress in the two horizontal directions is equal, and it is often treated as an axisymmetric problem. That is, σ2 = σ3; the false triaxial test is to test the sample under an axisymmetric stress state, and the false triaxial test is a conventional triaxial test.

However, in the actual rock and soil environment, the three principal stresses suffered by the rock mass are often different. The true triaxial test is to simulate the stress state of any small unit in the rock mass when the rock mass is under load. ; study the relationship between principal stress and strain and strength characteristics under the condition that the principal stress direction is fixed, that is, the constitutive relationship of soil; the sample is generally a cube or a rectangle; (i.e. X, Y, Z) apply the principal stresses σ1, σ2 and σ3 respectively (the relation of the principal stresses is σ1>σ2>σ3), that is, the sample applies three independent principal stresses σ1, σ1, σ2, σ3; the results measured by the true triaxial test method can better reflect the real constitutive relationship and are more complex than the false triaxial test, that is, the axisymmetric triaxial test.

In fact, many units do not have sufficient funds, and it is not realistic to have a fake triaxial tester and a real triaxial tester at the same time. In this way, it is necessary to develop a device that is simple in structure, easy to operate, and capable of performing true and false triaxial tests.

Contents of the invention

The purpose of the present invention is to provide a device capable of performing a true-false triaxial test, which has a simple structure, is easy to operate, and can carry out a true-false triaxial test.

In order to achieve the above object, the technical solution of the present invention is: a device capable of performing true and false triaxial tests, including a σ1 direction loading system, a σ2 direction loading system, and a σ3 direction loading system, and the σ1 direction loading system includes: vertical loading Piston, upper pressure head, lower pressure head; the σ2 direction loading system includes: manual operation loading part, pump loading part; the σ3 direction loading system includes: oil inlet, oil outlet; the vertical loading piston, The upper indenter and the lower indenter are arranged in the confining pressure chamber; the vertical loading piston is located directly above the upper indenter; the upper indenter and the lower indenter are respectively arranged on the upper and lower sides of the sample. The lower two ends; a left horizontal shaft and a right horizontal shaft are respectively arranged on both sides of the confining pressure chamber in axisymmetric form, and respectively pass through the outer wall of the confining pressure chamber; the right end of the pumping loading part is connected to the The left end of the left horizontal shaft, the left end of the manual operation loading part is connected to the right end of the right horizontal shaft; the oil inlet and the oil outlet are respectively arranged in axisymmetric form on the lower end of the outer wall of the confining pressure Left and right sides; a base is vertically connected to the lower end of the confining chamber;

When doing a true triaxial test, the σ2 direction loading system also includes a horizontal indenter; the horizontal indenter is a cuboid, and the section in contact with the sample is the same as the sample; the upper indenter, the The shape of the bottom surface of the lower pressure head is square and the same size as the bottom surface of the sample;

When doing a fake triaxial test, the cross-sections of the upper indenter and the lower indenter are circular and have the same size as the bottom surface of the sample, and the left horizontal shaft and the right horizontal shaft are respectively sealingly engage with the confining pressure chambers.

In the above technical solution, when doing true and false triaxial tests, the loading system in the σ1 direction, the loading system in the σ2 direction, and the loading system in the σ3 direction are independent of each other. When doing a true triaxial test, σ2≠σ3 is controlled by the left horizontal shaft, right horizontal shaft and oil pressure; when doing a fake triaxial test, σ2=σ3 is controlled by the oil pressure.

In the above technical solution, when doing a true triaxial test, there are two horizontal indenters, which are respectively arranged at the left and right ends of the sample. It is convenient to clamp the sample and prevent the sample from loosening and affecting the test results.

In the above technical solution, when performing a true triaxial test, the sample is a rectangular body with a square bottom, and the size of the sample is 50 mm in length and 100 mm in height. The bottom surface is square, and the height is generally greater than the side length of the bottom surface, so it is a rectangular body, which is convenient to apply three principal stresses σ1, σ2, σ3 to the sample, and keep σ2≠σ3.

In the above-mentioned technical solution, when doing the false triaxial test, the sample is a cylinder, and the size of the sample is 50mm in diameter and 100mm in height. In the pseudo-triaxial test, σ2 = σ3 is maintained by oil pressure, and a standard sample with a diameter of 50mm and a height of 100mm is generally used.

The present invention has the following advantages:

(1) Only by changing a small number of parts, both the true triaxial test and the false triaxial test can be done; when doing the true triaxial test, the present invention can be converted into a device that can carry out the true triaxial test. During false triaxial test, the present invention is converted into the device that can carry out false triaxial test;

(2) The present invention has simple structure and low cost;

(3) Save funds for scientific research units and provide convenience for researchers.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the true triaxial tester device of the present invention.

Fig. 2 is a schematic diagram of the overall structure of the false triaxial tester device of the present invention.

Fig. 3 is a schematic diagram of the structure of principal stresses and principal stress planes in the present invention.

In the figure 1-vertical loading piston, 2-upper pressure head, 3-lower pressure head, 4-manual operation loading part, 5-pump loading part, 6-horizontal pressure head, 7-sample, 8-oil inlet , 9-oil outlet, 10-base, 11-left horizontal shaft, 12-right horizontal shaft, 13-confined pressure chamber.

detailed description

The implementation of the present invention will be described in detail below in conjunction with the accompanying drawings, but they do not constitute a limitation to the present invention, and are only examples. At the same time, the advantages of the present invention are clearer and easier to understand through the description.

Referring to the accompanying drawings, it can be seen that a device capable of performing true and false triaxial tests includes a σ1 direction loading system, a σ2 direction loading system, and a σ3 direction loading system. The σ1 direction loading system includes: a vertical loading piston 1, an upper pressure head 2 , the lower pressure head 3; the σ2 direction loading system includes: manual operation loading part 4, pump loading part 5; the σ3 direction loading system includes: oil inlet 8, oil outlet 9; the vertical loading piston 1 , the upper pressing head 2 and the lower pressing head 3 are arranged in the confining pressure chamber 13; the vertical loading piston 1 is located directly above the upper pressing head 2; the upper pressing head 2 and the lower pressing head 3 are respectively arranged at the upper and lower ends of the sample 7; a left horizontal shaft 11 and a right horizontal shaft 12 are respectively arranged on both sides of the confining pressure chamber 13 in an axisymmetric form, and respectively pass through the confining pressure The outer wall of the chamber 13; the right end of the pump loading part 5 is connected to the left end of the left horizontal shaft 11, and the left end of the manual operation loading part 4 is connected to the right end of the right horizontal shaft 12; the oil inlet 8, the The oil outlets 9 are respectively arranged on the left and right sides of the lower end of the outer wall of the confining pressure chamber 13 in an axisymmetric form; a base 10 is vertically connected to the lower end of the confining pressure chamber 13;

When doing a true triaxial test, the σ2 direction loading system also includes a horizontal indenter 6; the horizontal indenter 6 is a cuboid, and the section in contact with the sample 7 is the same as the sample 7; The shape of the bottom surface of the head 2 and the lower pressure head 3 is square, and the size of the bottom surface of the sample 7 is the same;

When doing the false triaxial test, the sections of the upper indenter 2 and the lower indenter 3 are circular and have the same size as the bottom surface of the sample 7, and the left horizontal shaft 11, the The right horizontal shafts 12 are respectively in sealing engagement with the confining pressure chambers 13 (as shown in FIG. 1 and FIG. 2 ).

When doing true and false triaxial tests, the loading system in the σ1 direction, the loading system in the σ2 direction, and the loading system in the σ3 direction are independent of each other.

When doing a true triaxial test, there are two horizontal indenters 6, which are respectively arranged at the left and right ends of the sample 7.

When doing the true triaxial test, the sample 7 is a rectangular body with a square bottom.

When doing the pseudo-triaxial test, the sample 7 is a cylinder.

Referring to the accompanying drawings, it can be seen that the working process of a device capable of carrying out true and false triaxial tests of the present invention is as follows: when doing true triaxial tests, the device capable of carrying out true and false triaxial tests is refitted into a device capable of carrying out true triaxial tests. device, the sample 7 is a rectangular body with a square bottom, and the bottom surfaces of the upper indenter 2 and the lower indenter 3 are the same as that of the sample 7; The horizontal shaft 12 is close to the horizontal indenter 6, and then the pump loading part 5 is operated to make the left horizontal shaft 11 close to the horizontal indenter 6, thereby exerting a σ2 direction force on the sample 7; 7 Apply a vertical axial force σ1; apply a σ3 direction force to the sample 7 through the oil pressure of the oil inlet 8 and oil outlet 9; when doing a false triaxial test, refit the device that can perform a true triaxial test Become the device that can carry out false triaxial test, at this moment, remove the horizontal indenter 6 in the device that can carry out true triaxial test, change sample 7 into cylinder; Good sample 7 is fitted with rubber; The loading piston 1 exerts a vertical axial force σ1 on the sample 7; the oil pressure through the oil inlet 8 and oil outlet 9 exerts σ2 and σ3 direction forces on the sample 7.

In order to more clearly illustrate the advantages of the device capable of carrying out true and false triaxial tests of the present invention compared with the true triaxial test device and the false triaxial test device, the staff compared these three devices: For some units that need both the true triaxial test of rock and the false triaxial test of rock, the cost of the present invention is only 900,000, the floor space is small, and the true triaxial test and false triaxial test of rock can be carried out. Triaxial test, and the total cost of the true triaxial test device and the false triaxial test device needs to be about 1.5 million, and the area is large. It is necessary to use the true triaxial test device and the false triaxial test device to perform the true triaxial test of the rock. , Pseudo triaxial test.

Other unspecified parts belong to the prior art.

Claims (5)

1. can carry out a device for true and false triaxial test, add including σ 1 direction loading system, σ 2 direction loading system, σ 3 direction Loading system, described σ 1 direction loading system includes: Vertical loading piston (1), seaming chuck (2), push-down head (3)；Described σ 2 direction Loading system includes: manual operation loading section (4), pump move loading section (5)；Described σ 3 direction loading system includes: oil-feed Mouth (8), oil-out (9)；Described Vertical loading piston (1), described seaming chuck (2), described push-down head (3) are arranged at confined pressure room (13) in；Described Vertical loading piston (1) is positioned at directly over described seaming chuck (2)；Described seaming chuck (2) and described push-down head (3) upper/lower terminal of sample (7) it is respectively arranged at；There are left horizontal axostylus axostyle (11), right horizontal axostylus axostyle (12) respectively with axisymmetric shape Formula is arranged at (13) both sides, described confined pressure room and is each passed through described confined pressure room (13) outer wall；It is right that described pump moves loading section (5) End is connected to described left horizontal axostylus axostyle (11) left end, and described manual operation loading section (4) left end is connected to described right trunnion axis Bar (12) right-hand member；Described oil-in (8), described oil-out (9) are arranged at described confined pressure room (13) outward with axial symmery shape respectively The arranged on left and right sides of wall lower end；Base (10) is had to be vertically connected at described confined pressure room (13) lower end；

When doing true triaxial test, σ 2 direction loading system also includes horizontal pressure head (6)；Described horizontal pressure head (6) is cuboid, And the cross section that contacts with described sample (7) is identical with described sample (7)；Described seaming chuck (2), the bottom surface of described push-down head (3) It is shaped as square and identical with described sample (7) bed-plate dimension；

When rehearsing triaxial test, described seaming chuck (2), the cross section of described push-down head (3) be circle and with described sample (7) bed-plate dimension is identical, and described left horizontal axostylus axostyle (11), described right horizontal axostylus axostyle (12) are close with described confined pressure room (13) respectively Sealing-in is closed.

A kind of device carrying out true and false triaxial test the most according to claim 1, it is characterised in that: doing true and false three axles During test, described σ 1 direction loading system, described σ 2 direction loading system, described σ 3 direction loading system are each independent.

A kind of device carrying out true and false triaxial test the most according to claim 1 and 2, it is characterised in that: doing true three During shaft experiment, described horizontal pressure head (6) totally two and be respectively arranged at described sample (7) left and right two ends.

A kind of device carrying out true and false triaxial test the most according to claim 3, it is characterised in that: doing true triaxial examination When testing, described sample (7) be bottom surface be foursquare cuboid.

A kind of device carrying out true and false triaxial test the most according to claim 4, it is characterised in that: in the three axle examinations that rehearse When testing, described sample (7) is cylinder.