Radial strain measuring device for sample in triaxial test

Abstract

The utility model discloses a radial strain measuring device for a sample in a triaxial test. The radial strain measuring device comprises a steel retaining ring, two hinged protective plates and a flexible optical fiber sensor, the steel retaining ring comprises two semicircular steel retaining rings and a connecting mechanism; the middle parts of the outer end surfaces of the two semicircular steel retaining rings are respectively provided with a semicircular arc-shaped groove; the connecting mechanism comprises a spring hinge connected between one ends of the two semicircular steel retaining rings, a pair of connecting supports symmetrically fixed at the other ends of the two semicircular steel retaining rings, and a connecting steel wire slidably connected between the two supports; the two hinged protection plates are hinged to the top surfaces of the middle parts of the two semicircular steel protection rings in a central symmetry manner and are adhered to the outer surface of the soil body sample; the flexible optical fiber sensor is embedded in the grooves of the two semicircular steel retaining rings, and the two ends of the flexible optical fiber sensor are connected to the two-way sensor connector, so that the flexible optical fiber sensor forms a circular ring, and the two-way sensor connector is located between the two supports. The utility model has the characteristics of simple structure and convenience in installation.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of radial strain measuring devices of sample in triaxial test. BACKGROUND

[0002] Triaxial test is one of important tests for determining soil mechanical parameters. Traditional triaxial test is usually to fix the two ends of cylindrical soil sample, and to carry out vertical shear to obtain the stress-strain relationship of soil sample in vertical direction. There is a lack of measuring device for radial strain of sample. Then, soil sample is a very complex non-linear elastic material, and anisotropy characteristics cannot be ignored. Therefore, it is very meaningful to accurately measure the radial strain of soil sample. At present, the method for measuring the radial strain of soil sample includes using Hall effect sensor, laser displacement meter, miniature inclinometer and other instruments to measure local radial strain. The instrument is difficult to install, and the operation is complex. Moreover, it is impossible to measure the overall strain of soil sample in circumferential direction. SUMMARY

[0003] The utility model aims at overcoming the defects of prior art and providing a radial strain measuring device of sample in triaxial test, which has the advantages of simple structure, easy installation and low cost, and can accurately measure the overall radial deformation of soil sample.

[0004] The utility model aims at overcoming the defects of prior art and providing a radial strain measuring device of sample in triaxial test, which has the advantages of simple structure, easy installation and low cost, and can accurately measure the overall radial deformation of soil sample.

[0005] The steel guard ring comprises two semicircular steel guard rings and a connecting mechanism. A semicircular recess is formed in the middle of the outer end surface of each semicircular steel guard ring. The connecting mechanism comprises a spring hinge, a pair of connecting supports and a connecting steel wire. The spring hinge is connected between one end of the two semicircular steel guard rings. The other end of the two semicircular steel guard rings is fixed to the connecting supports in a one-to-one correspondence and in a symmetrical manner. The connecting steel wire is slidably connected between the two supports.

[0006] The hinged guard plate comprises an arc-shaped plate with a curvature that is adapted to the curvature of the outer surface of the cylindrical soil sample and a hinged block that extends radially from the middle of the arc-shaped plate. The two hinged guard plates are hingedly connected to the middle top surface of the two semicircular steel guard rings in a central symmetrical manner through the hinged blocks and hinge shafts. The arc-shaped plates of the two hinged guard plates are located on the inner side of the two semicircular steel guard rings in a one-to-one correspondence, and the arc-shaped plates of the two hinged guard plates are centrally symmetrically attached to the outer surface of the soil sample.

[0007] The flexible optical fiber sensor is embedded in the recess of the two semicircular steel guard rings. The two ends of the flexible optical fiber sensor are connected to the two ends of a two-way sensor connector in a one-to-one correspondence, so that the flexible optical fiber sensor forms a circular ring. The two-way sensor connector is located between the two supports.

[0008] The radial strain measuring device for soil sample in triaxial test of the application has the characteristics of simple structure, convenient production, low cost, convenient installation and accurate measurement of the overall radial deformation of the soil sample.

[0009] The radial strain measuring device for soil sample in triaxial test of the application has the characteristics of simple structure, convenient production, low cost, convenient installation and accurate measurement of the overall radial deformation of the soil sample.

[0010] The radial strain measuring device for soil sample in triaxial test of the application has the characteristics of simple structure, convenient production, low cost, convenient installation and accurate measurement of the overall radial deformation of the soil sample. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a plan view of the radial strain measuring device for soil sample in triaxial test of the application;

[0012] Figure 2 is Figure 1 the A-A view in DETAILED DESCRIPTION

[0013] The radial strain measuring device for soil sample in triaxial test of the application has the characteristics of simple structure, convenient production, low cost, convenient installation and accurate measurement of the overall radial deformation of the soil sample.

[0014] Please refer to Figure 1 and Figure 2 The radial strain measuring device for soil sample in triaxial test of the application has the characteristics of simple structure, convenient production, low cost, convenient installation and accurate measurement of the overall radial deformation of the soil sample.

[0015] The steel ring comprises two semicircular steel rings 1 and a connecting mechanism; wherein,

[0016] A semicircular recess 10 is formed in the middle of the outer end surface of each of the two semicircular steel rings 1;

[0017] The connecting mechanism comprises a spring hinge 2, a pair of connecting supports 3 and a connecting steel wire 4; the two ends of the spring hinge 2 are respectively connected to one end of the two semicircular steel rings 1 by rivets 20; the other end of the two semicircular steel rings 1 is fixed with a pair of connecting supports 3 in one-to-one correspondence and symmetry, each connecting support 3 comprises a horizontal plate 31 fixed to the outer surface of one end of the semicircular steel ring 1 and a vertical plate 32 connected to the outer side surface of the horizontal plate 31, and a steel wire hole is horizontally formed in the vertical plate 32; the connecting steel wire 4 is slidably connected to the steel wire holes of the two supports 3.

[0018] The hinged protecting plate 5 comprises an arc-shaped plate 51 with a curvature adapted to the curvature of the outer surface of the cylindrical soil sample and a hinge block 52 extending radially from the middle of the arc-shaped plate 51; the two hinged protecting plates 5 are each hinged on the middle top surface of the two half-cylindrical steel protecting rings 1 through the hinge block 52 and the hinge shaft, the arc-shaped plates 51 of the two hinged protecting plates 5 are located on the inner side of the two half-cylindrical steel protecting rings 1 in one-to-one correspondence, and the arc-shaped plates 51 of the two hinged protecting plates 5 are centrally symmetrically pasted on the outer surface of the soil sample;

[0019] The flexible optical fiber sensor 6 is embedded in the groove 10 of the two half-cylindrical steel protecting rings 1, and the two ends of the flexible optical fiber sensor 6 are connected to the two ends of a two-way sensor joint 7 in one-to-one correspondence, so that the flexible optical fiber sensor 6 forms a ring, and the two-way sensor joint 7 is located between the two supports 3.

[0020] The main process of the radial strain measuring device in the utility model during testing is as follows:

[0021] 1. First, the two half-cylindrical steel protecting rings 1 of the radial strain measuring device are embraced at the to-be-tested section of the soil sample, the arc-shaped plates 51 of the two hinged protecting plates 5 that have been hinged on the two half-cylindrical steel protecting rings 1 are pasted on the outer surface of the soil sample, the two half-cylindrical steel protecting rings 1 are fixed on the soil sample, and a connecting steel wire 4 is arranged in the steel wire perforation of the vertical plate 32 of the support 3 at the two ends of the two half-cylindrical steel protecting rings 1; then the signal line 60 of the flexible optical fiber sensor 6 that has been embedded in the groove 10 of the two half-cylindrical steel protecting rings 1 and has formed a ring is connected with a data collector;

[0022] 2. When the soil sample is tested, radial expansion deformation occurs, so that the two hinged protecting plates 5 are expanded, and then the two half-cylindrical steel protecting rings 1 are expanded in the radial direction, so that the flexible optical fiber sensor 6 is also deformed, and the data collector connected with the flexible optical fiber sensor 6 can record the deformation of the flexible optical fiber sensor 6 through a computer.

[0023] The two half-cylindrical steel protecting rings 1 in the radial strain measuring device are connected through the spring hinge 2 at one end, so that the whole steel protecting ring can stably contact the soil sample and ensure deformation conduction; the two hinged protecting plates 5 serve to conduct the radial deformation of the soil sample; when the two half-cylindrical steel protecting rings 1 expand in the radial direction, the connecting steel wire 4 guides the two half-cylindrical steel protecting rings 1 to move horizontally, thereby reducing the radial deformation error; the flexible optical fiber sensor 6 is embedded in the groove 10 of the two half-cylindrical steel protecting rings 1, and the two ends of the flexible optical fiber sensor 6 are connected to the two-way sensor joint 7, thereby forming a ring and ensuring that the flexible optical fiber sensor 6 is uniformly stressed.

[0024] The above examples are only for illustrating the utility model, and are not limitation to the utility model. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the utility model, and all equivalent technical schemes should belong to the scope of the utility model, which should be limited by the claims.

Claims

1. A device for measuring the radial strain of a sample in triaxial test, comprising a steel ring, two hinged guards and a flexible optical fiber sensor; characterized in that, the steel ring comprises two semicircular steel rings and a connecting mechanism; a semicircular arc-shaped groove is formed in the middle of the outer end surface of each of the two semicircular steel rings; the connecting mechanism comprises a spring hinge, a pair of connecting supports and a connecting steel wire; the spring hinge is connected between one end of the two semicircular steel rings; the pair of connecting supports are fixed at the other end of the two semicircular steel rings in a one-to-one and symmetrical manner; the connecting steel wire is slidably connected between the two supports; the hinged guard comprises an arc-shaped plate with a curvature adapted to the curvature of the outer surface of the cylindrical soil sample and a hinged block extending radially from the middle of the arc-shaped plate; the two hinged guards are each hingedly connected to the middle top surface of the two semicircular steel rings in a central symmetrical manner through the hinged block and the hinge shaft, so that the arc-shaped plates of the two hinged guards are located on the inner side of the two semicircular steel rings in a one-to-one correspondence, and the arc-shaped plates of the two hinged guards are centrally symmetrically pasted on the outer surface of the soil sample; the flexible optical fiber sensor is embedded in the groove of the two semicircular steel rings, and the two ends of the flexible optical fiber sensor are connected to the two ends of a two-way sensor connector in a one-to-one correspondence, so that the flexible optical fiber sensor forms a circular ring, and the two-way sensor connector is located between the two supports.

2. The apparatus for measuring the radial strain of a sample in a triaxial test according to claim 1, wherein the support comprises a horizontal plate fixed on the outer surface of the end of the semicircular steel ring and a vertical plate connected to the outer side of the horizontal plate, and a steel wire through hole is formed horizontally on the vertical plate, and the connecting steel wire is slidably inserted into the steel wire through hole.

3. The apparatus for measuring the radial strain of a sample in a triaxial test according to claim 1, wherein the two ends of the spring hinge are each connected to one end of the two semicircular steel rings in a one-to-one correspondence through rivets.

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