CN112665520B

CN112665520B - Device and method for measuring axial deformation by laser

Info

Publication number: CN112665520B
Application number: CN202110087658.0A
Authority: CN
Inventors: 彭绍驰; 经来旺; 李树文
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2022-08-05
Anticipated expiration: 2041-01-22
Also published as: CN112665520A

Abstract

A device and a method for measuring axial deformation by laser are used for measuring axial deformation in geotechnical experiments and can effectively solve the defects of high cost, easy damage and inconvenient operation of the conventional axial deformation measuring device. The device comprises an upper clamp 1, a fixed base plate 2, a hydraulic large arm fixer 3, a laser device 4, a hydraulic large arm 5, a reflection ring 6, a hydraulic small arm 7, an oil tank 8 and a lower clamp 9. The test block has the advantages of low manufacturing cost, difficult damage, simple operation and real-time and high-precision reflection of the axial deformation of the test block.

Description

Device and method for measuring axial deformation by laser

Technical Field

The invention belongs to the technical field of geotechnical tests and relates to a device and a method for measuring axial deformation by using laser.

Background

At present, in geotechnical test, the axial deformation of measuring the test block mainly adopts the grating extensometer, and the device not only cost is high, very takes place to damage easily in the experiment, does not have reasonable zero setting mode moreover, only leans on adjusting the top pressure head and realizes zero setting, and the time is of a specified duration then the pressure head is fixed not lived, causes unnecessary experimental error. Axial deformation is a prerequisite for researching damage and deformation of rock and soil, so that the research on an axial deformation device and method which are high in precision, low in manufacturing cost, not easy to damage and simple to use is very important.

Disclosure of Invention

In order to overcome the defects of high manufacturing cost, easy damage and inconvenient use of the conventional axial deformation measuring device, the invention provides the device and the method for measuring the axial deformation by using the laser, which have the advantages of low manufacturing cost, difficult damage, simple operation and capability of reflecting the axial deformation of the test block in real time and high precision.

The technical scheme adopted by the invention for solving the problems is as follows:

a device and a method for measuring axial deformation by laser can reflect axial deformation of a test block with high precision in a time-sharing manner, and is used for measuring the axial deformation of the test block in a soil test. The opening angle of the reflection ring 6 is 30 degrees, repeated reflection of laser in the ring is prevented, the reflection ring is fixed on the hydraulic small arm 7, the hydraulic small arm 7 is fixed on the lower portion of the hydraulic big arm 5, the bottom of the hydraulic big arm is connected with the oil tank 8, and the top of the hydraulic big arm is fixed on the hydraulic big arm fixer 3. The laser device 4 is fixed on the outer side of the hydraulic large arm fixer 3, the inside of the hydraulic large arm fixer is connected with the upper clamp 1 through the fixing base plate 2, and the oil tank 8 is connected with the lower clamp 9 through the fixing base plate 2.

The method for measuring axial deformation by laser comprises the following steps

In the first step, the large arm valve 11 and the small arm valve 10 are opened, and the upper clamp 1 is lowered to a narrow gap between the upper clamp and the test piece.

And secondly, zeroing, closing the large arm valve 11, opening the small arm valve 10, regulating the lifting of the hydraulic small arm 7 through the pressure exerted by the oil tank 8, opening the laser device 4, and indicating that the precise zeroing is performed when only one light spot exists on the reflecting ring 6.

And thirdly, performing a compression experiment, closing the small arm valve 10, and fixing the hydraulic small arm 7 to fix the reflection ring 6. The compression can be performed by opening the large arm valve 11, and as the compression proceeds, a series of equally spaced spots are formed on the reflective ring 6, resulting in the arc length Δ S of two adjacent spots.

And fourthly, calculating axial deformation, and obtaining a formula of a reflection angle according to the incident angle theta of the laser device 4 and the arc length delta S of the two adjacent light spots obtained in the third step:

the calculation formula for obtaining the axial deformation is as follows:

the invention has the beneficial effects that: the test block has the advantages of low manufacturing cost, difficult damage, simple operation and real-time and high-precision reflection of the axial deformation of the test block.

Drawings

The invention is further illustrated with reference to the following figures and examples:

FIG. 1 is a perspective view of a three-dimensional device of the present invention;

FIG. 2 is a front view of the three-dimensional apparatus of the present invention;

FIG. 3 is a schematic diagram of formula derivation according to the present invention;

fig. 4 is a hydraulic circuit diagram of the present invention.

In the figure, 1, an upper clamp, 2, a fixed backing plate, 3, a hydraulic large arm fixer, 4, a laser device, 5, a hydraulic large arm, 6, a reflection ring, 7, a hydraulic small arm, 8, an oil tank, 9, a lower clamp, 10, a small arm valve and 11, a large arm valve are arranged.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

In the figure 1, the opening angle of a reflection ring 6 is 30 degrees, the repeated reflection of laser in the ring is prevented, the reflection ring is fixed on a hydraulic small arm 7, the hydraulic small arm 7 is fixed at the lower part of a hydraulic big arm 5, the bottom of the hydraulic big arm is connected with an oil tank 8, and the top of the hydraulic big arm is fixed on a hydraulic big arm fixer 3. The laser device 4 is fixed on the outer side of the hydraulic large arm fixer 3, the inside of the hydraulic large arm fixer is connected with the upper clamp 1 through the fixing base plate 2, and the oil tank 8 is connected with the lower clamp 9 through the fixing base plate 2. The lower clamp 9 is fixed, and the movement of the upper clamp 1 drives the fixed base plate 2 and the hydraulic large arm fixer 3 to move downwards, so as to drive the hydraulic large arm 5 to move.

In fig. 1, the reflection ring 6 is connected to the hydraulic arm 7, and the operation of the hydraulic arm 7 controls the operation of the reflection ring 6.

In fig. 4, when the large arm valve 11 and the small arm valve 10 are both opened, the downward movement of the upper clamp 1 will simultaneously drive the hydraulic large arm 5 and the hydraulic small arm 7 to move downward, and further drive the laser device 4 and the reflective ring 6 to move downward.

In fig. 4, when the large arm valve 11 is closed and the small arm valve 10 is opened, the pressure of the oil tank 8 is adjusted, so that the hydraulic small arm 7 moves, and further the reflection ring 6 moves, thereby achieving the purpose of zero adjustment.

In fig. 4, when the small arm valve 10 is closed and the large arm valve 11 is opened, the hydraulic large arm 5 can move to drive the laser device 4 to move, so as to achieve the purpose of measuring the axial deformation.

Claims

1. A method for measuring axial deformation by laser uses a device for measuring axial deformation by laser, and the device comprises an upper clamp (1), two fixed base plates (2), a hydraulic large arm fixer (3), a laser device (4), a hydraulic large arm (5), a reflection ring (6), a hydraulic small arm (7), an oil tank (8) and a lower clamp (9); the opening angle of the reflection ring (6) is 30 degrees, repeated reflection of laser in the ring is prevented, the reflection ring is fixed on a hydraulic small arm (7), the hydraulic small arm (7) is fixed at the lower part of a hydraulic big arm (5), the bottom of the hydraulic big arm is connected with an oil tank (8), and the top of the hydraulic big arm is fixed on a hydraulic big arm fixer (3); the laser device (4) is fixed on the outer side of the hydraulic large arm fixer (3), the inner side of the hydraulic large arm fixer (3) is connected with the upper clamp (1) through one fixing base plate (2), and the oil tank (8) is connected with the lower clamp (9) through the other fixing base plate (2);

the method comprises the following steps:

the method comprises the following steps that firstly, a large arm valve (11) and a small arm valve (10) are opened, at the moment, an upper clamp (1) moves downwards to drive a hydraulic large arm (5) and a hydraulic small arm (7) to move downwards at the same time, further drive a laser device (4) and a reflection ring (6) to move downwards, and enable the upper clamp (1) to be lowered to a narrow gap away from a test piece;

secondly, zeroing, closing a large arm valve (11), opening a small arm valve (10), adjusting the lifting of a hydraulic small arm (7) through the pressure exerted by an oil tank (8), opening a laser device (4), and indicating that the zeroing is accurate when only one light spot exists on a reflection ring (6);

thirdly, performing a compression experiment, closing the small arm valve (10), and fixing the hydraulic small arm (7) to fix the reflection ring (6); the large arm valve (11) is opened, the compression can be carried out, a series of equidistant light spots are formed on the reflecting ring (6) along with the compression, and the arc length delta S of two adjacent light spots is obtained;

and fourthly, calculating axial deformation, and obtaining a formula of a reflection angle according to the incident angle theta of the laser device (4) and the arc length delta S of two adjacent light spots obtained in the third step:

the calculation formula for obtaining the axial deformation is as follows: