CN220289459U

CN220289459U - Real-time low-temperature frost heaving deformation testing device based on three-dimensional DIC

Info

Publication number: CN220289459U
Application number: CN202322120143.3U
Authority: CN
Inventors: 徐颖; 岳腾泷; 马帅帅; 吴帮标; 夏开文
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2023-08-08
Filing date: 2023-08-08
Publication date: 2024-01-02
Anticipated expiration: 2033-08-08

Abstract

The utility model discloses a real-time low-temperature frost heaving deformation testing device based on a three-dimensional DIC, which is applied to the technical field of rock engineering. Including real-time low temperature test system, temperature calibration system and three-dimensional DIC monitoring system, real-time low temperature test system includes real-time low temperature case and temperature control case, real-time low temperature case sets up in the temperature control case top, real-time low temperature incasement is provided with the rock sample, real-time low temperature case openly is provided with the glass observation window, rock sample aligns with the glass observation window, real-time low temperature case is provided with adjustable light source all around, temperature calibration system gathers the temperature data of rock sample, three-dimensional DIC monitoring system gathers the DIC image data of rock sample. The device provided by the utility model has the advantages of simple structure, easiness in operation and high test precision, can test the frost heaving deformation characteristics of the rock under the low-temperature condition in real time and in a whole area, and provides a theoretical basis for the physical and mechanical properties of the rock in alpine regions and engineering application research thereof.

Description

Real-time low-temperature frost heaving deformation testing device based on three-dimensional DIC

Technical Field

The utility model relates to the technical field of rock engineering, in particular to a real-time low-temperature frost heaving deformation testing device based on a three-dimensional DIC.

Background

At present, people have better knowledge of the physical and mechanical properties of rock under normal temperature and high temperature conditions, and do a lot of research work on related theory and test, but the knowledge of the physical and mechanical properties of water-containing frozen rock under low temperature conditions is not enough. In the rock engineering of cold areas, such as the fields of rock slopes, rock roadbeds, tunnels, surrounding rock safety of a low-temperature storage warehouse of liquefied natural gas by a manual freezing method, the most important is the determination of rock physical and mechanical parameters under the low-temperature freezing condition. Under the low-temperature environment, when water in the water-rich engineering Cheng Yanti is frozen, about 9% of volume expansion is generated, and the rock mass can generate frost heaving and thawing shrinkage effects, so that the stress state of the support body and the stability of the rock mass engineering are obviously influenced. Therefore, the research on the low-temperature deformation characteristics of the rock has important significance for defending and controlling the rock mass freezing injury and the engineering design of the rock mass in cold areas. The existing method for measuring the frost heaving deformation of the rock materials is mainly divided into contact measurement and non-contact measurement. The contact type measuring method mostly adopts a low-temperature strain gauge measuring technology. The low-temperature strain gauge for measuring rock deformation has the advantages of low cost, simplicity and convenience in operation and the like, however, the resistance value of an ideal strain gauge for testing frost heaving deformation only changes along with the strain, and is not influenced by other factors. In practice, the resistance of the strain gage is greatly affected by the ambient temperature (including the test piece). The resistance change due to the ambient temperature change is almost of the same order of magnitude as the resistance change due to the specimen strain, resulting in a large measurement error. Bridge compensation is a common method for eliminating temperature strain errors, which complicates the measurement of frost heaving deformation. In addition, the low-temperature strain gauge can only measure frost heaving deformation of the pasting position of the rock strain gauge, and cannot actually measure strain distribution in the whole rock area. The frost heaving deformation and the strain of a specific position are used for estimating the frost heaving deformation and the actual rock deformation characteristics of the whole rock sample, so that larger errors can exist, and the actual deformation condition of the rock in a low-temperature environment can not be accurately described. In the non-contact measurement method, the CT scanning technology can realize the real-time monitoring of the frost heaving deformation of the rock, but the influence of the fertility of a high-definition CT image in the rock under a low-temperature environment acquired based on a CT scanning system is likely to have the phenomena of inaccurate identification of micro-cracks and artifact, so that a certain test error is caused. In addition, CT scanning systems are expensive and complex to operate in combination with real-time cryogenic systems. Therefore, how to provide a real-time low-temperature frost heaving deformation testing device capable of accurately measuring different lithology and rock in different saturation states is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the utility model provides a real-time low-temperature frost heaving deformation testing device based on a three-dimensional DIC, which is characterized in that a rock sample is placed in a real-time low-temperature box with a transparent observation window, the frost heaving deformation characteristics and the strain distribution conditions of the rock are measured by using the three-dimensional DIC technology based on speckle and a CCD camera, and the whole-area real-time continuous monitoring of the frost heaving deformation of the rock material is realized under different temperature conditions.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the utility model provides a real-time low temperature frost heaving deformation testing arrangement based on three-dimensional DIC, includes real-time low temperature test system, temperature calibration system and three-dimensional DIC monitoring system, real-time low temperature test system includes real-time low temperature case and temperature control box, real-time low temperature case sets up the temperature control box top, be provided with the rock sample in the real-time low temperature case, real-time low temperature case openly is provided with the glass observation window, the rock sample with the glass observation window aligns, be provided with adjustable light source around the real-time low temperature case, temperature calibration system gathers the temperature data of rock sample, three-dimensional DIC monitoring system gathers the DIC image data of rock sample.

Optionally, the control by temperature change case right side is provided with the business turn over water pipe, be provided with the business turn over valve on the business turn over water pipe, the control by temperature change case pass through the business turn over water pipe with real-time low temperature case is connected, be provided with the basin in the control by temperature change case, be provided with alcohol in the basin, alcohol passes through the business turn over water pipe be in real-time low temperature case with the control by temperature change incasement circulation flow.

Optionally, the water inlet and outlet pipe is a copper pipe, and the water inlet and outlet pipe is wrapped with heat preservation sponge.

Optionally, the surface of the temperature control box is provided with a temperature control panel, a refrigerant, a compressor, a condenser and an evaporator are arranged in the temperature control box, the compressor, the condenser and the evaporator are sequentially connected to form a circulation loop, and the refrigerant is arranged in the circulation loop.

Optionally, the temperature calibration system includes temperature sensor, temperature data acquisition line and temperature data acquisition appearance, temperature sensor pastes on the rock sample, temperature sensor connects the temperature data acquisition line, temperature data acquisition line pass through mounting hole on the real-time low temperature case with temperature data acquisition appearance is connected.

Optionally, the three-dimensional DIC monitoring system includes speckle paper, two CCD cameras, synchronous camera trigger appearance, data transmission line and computer, the speckle paper is pasted on rock sample surface, two CCD cameras symmetry sets up real-time low temperature case both sides, the CCD camera passes through the data transmission line with synchronous camera trigger appearance is connected, synchronous camera trigger appearance with the computer is connected.

Optionally, be provided with height-adjustable's location backing plate in the real-time low temperature case, the rock sample sets up on the location backing plate, be provided with backing plate lift control panel on the real-time low temperature case.

Optionally, a light source control panel is arranged on the real-time low-temperature box.

Optionally, a fixing device is arranged between the real-time low-temperature box and the temperature control box.

Optionally, the glass observation window is double-layer hollow, and double-layer sealant is arranged around the glass observation window.

Compared with the prior art, the utility model provides the real-time low-temperature frost heaving deformation testing device based on the three-dimensional DIC, which has the following beneficial effects:

1. the device has simple structure, easy operation and high test precision, can test the frost heaving deformation characteristics of the rock under the low-temperature condition in real time and in a whole area, and provides a theoretical basis for the physical and mechanical properties of the rock in alpine regions and the engineering application research thereof;

2. the utility model is provided with a temperature monitoring device, and can realize real-time monitoring of the temperature change condition of the rock sample surface by utilizing a data acquisition system to obtain the relationship of time, temperature and strain;

3. the non-contact measurement of the frost heaving deformation of the rock sample is realized based on the three-dimensional DIC technology, the rock sample is monitored in real time under the low temperature condition, the testing process is simple, and the problems of larger error and complex operation of the current frost heaving deformation test by using the low temperature strain gauge are solved;

4. the real-time low-temperature test can better simulate frost heaving deformation of the rock and rock materials in real natural environments such as alpine mountain areas, and the obtained deformation and temperature response of the rock under the low-temperature effect are more in line with the real conditions.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present utility model, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a front view of a deformation testing apparatus of the present utility model;

FIG. 2 is a left side view of the deformation testing apparatus of the present utility model;

FIG. 3 is a schematic diagram of a three-dimensional DIC test system according to the utility model;

in the figure: 1-real-time low-temperature box, 2-glass observation window, 3-positioning backing plate, 4-backing plate lifting control panel, 5-light source, 6-light source control panel, 7-mounting hole, 8-temperature control box, 9-temperature control panel, 10-fixing device, 11-inlet and outlet valve, 12-inlet and outlet water pipe, 13-CCD camera, 14-synchronous camera trigger instrument, 15-data transmission line, 16-computer, 17-temperature data acquisition line, 18-temperature data acquisition instrument, 19-temperature sensor and 20-rock sample.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The embodiment of the utility model discloses a real-time low-temperature frost heaving deformation testing device based on a three-dimensional DIC, which comprises a real-time low-temperature testing system, a temperature calibration system and a three-dimensional DIC monitoring system, wherein the real-time low-temperature testing system comprises a real-time low-temperature box 1 and a temperature control box 8, the real-time low-temperature box 1 is arranged above the temperature control box 8, a rock sample 20 is arranged in the real-time low-temperature box 1, a glass observation window 2 is arranged on the front surface of the real-time low-temperature box 1, the rock sample 20 is aligned with the glass observation window 2, adjustable light sources 5 are arranged around the real-time low-temperature box 1, the temperature calibration system collects temperature data of the rock sample 20, and the three-dimensional DIC monitoring system collects DIC image data of the rock sample 20.

Further, a water inlet and outlet pipe 12 is arranged on the right side of the temperature control box 8, an inlet and outlet valve 11 is arranged on the water inlet and outlet pipe 12, the temperature control box 8 is connected with the real-time low-temperature box 1 through the water inlet and outlet pipe 12, a water tank is arranged in the temperature control box 8, alcohol is arranged in the water tank, and the alcohol circularly flows in the real-time low-temperature box 1 and the temperature control box 8 through the water inlet and outlet pipe 12.

Further, the water inlet and outlet pipe 12 is a copper pipe, and the water inlet and outlet pipe 12 is wrapped with heat preservation sponge.

Further, a temperature control panel 9 is arranged on the surface of the temperature control box 8, a refrigerant, a compressor, a condenser and an evaporator are arranged in the temperature control box 8, the compressor, the condenser and the evaporator are sequentially connected to form a circulation loop, and the refrigerant is arranged in the circulation loop.

Further, the gaseous refrigerant in the temperature control box 8 is transferred to the condenser through the compressor, the condenser condenses the gaseous refrigerant into a liquid state and transfers the liquid state to the evaporator, the evaporator evaporates the liquid state refrigerant into a gaseous state, the evaporation process absorbs heat, the cooling effect is achieved, and meanwhile the gaseous refrigerant is transferred back to the compressor, so that a circulation process is formed. Because alcohol is arranged in the water tank, in the evaporation process, the heat of the alcohol is absorbed by the refrigerant, so that the temperature of the alcohol is reduced, the alcohol is used as a secondary refrigerant, and flows in the real-time low-temperature box 1 and the temperature control box 8 in a circulating way through the water inlet and outlet pipe 12 to absorb the heat in the real-time low-temperature box 1, so that the temperature in the real-time low-temperature box 1 is reduced. After the temperature in the real-time low-temperature box 1 reaches the designated temperature, the temperature in the real-time low-temperature box 1 is stabilized by controlling the evaporation capacity of the liquid refrigerant and the flow of alcohol (secondary refrigerant) through the water inlet and outlet pipes so as to realize accurate temperature regulation. The real-time low-temperature test system can realize controllable cooling rate and stable low-temperature environment, the cooling rate is 1 ℃/min, and the temperature change range is-60 ℃ to 50 ℃.

Further, the temperature calibration system comprises a temperature sensor 19, a temperature data acquisition line 17 and a temperature data acquisition instrument 18, wherein the temperature sensor 19 is stuck on a rock sample 20, the temperature sensor 19 is connected with the temperature data acquisition line 17, and the temperature data acquisition line 17 is connected with the temperature data acquisition instrument 18 through a mounting hole 7 on the real-time low-temperature box 1.

Furthermore, the aperture of the mounting hole 7 is 10mm, and the sealing plug is arranged at the mounting hole 7 to ensure the cooling effect of the real-time low-temperature box 1.

Furthermore, in one embodiment of the utility model, the temperature sensor 19 is a platinum resistance temperature sensor, the temperature application range is-200 ℃ to 400 ℃, the temperature sensor has the advantages of low price, simple installation and high sensitivity at low temperature, and meanwhile, the temperature sensor is provided with a low temperature resistant data acquisition line (the temperature resistant range is-90 ℃ to 250 ℃) and is attached to the low temperature environment of the test, so that the real-time and continuous monitoring of the surface temperature of the rock sample can be achieved. In the test process, the temperature sensor 19 is stuck on the central line of the non-speckle area of the rock sample 20 by using epoxy resin glue, and the average value of the two temperature sensors 19 is taken as the real-time temperature value of the surface of the rock sample 20 at 1/3 and 2/3 of the upper surface of the rock sample 20.

Further, the three-dimensional DIC monitoring system comprises speckle paper, two CCD cameras 13, a synchronous camera trigger 14, a data transmission line 15 and a computer 16, wherein the speckle paper is stuck on the surface of a rock sample 20, the two CCD cameras 13 are symmetrically arranged on two sides of the real-time low-temperature box 1, the CCD cameras 13 are connected with the synchronous camera trigger 14 through the data transmission line 15, and the synchronous camera trigger 14 is connected with the computer 16.

Further, in one embodiment of the present utility model, the speckle paper is selected to test for speckle having low temperature sensitivity and low temperature large deformation characteristics, and prevent cracking and falling-off of the low temperature speckle.

Further, in one embodiment of the present utility model, the central axes of the two CCD cameras 13 intersect at an angle of between 30 ° and 60 °, and the intersection point of the central axes of the two CCD cameras 13 is located on the surface of the rock sample 20, and the surface of the rock sample 20 is covered with the speckle paper, so as to ensure no obvious bubbles. The synchronous camera trigger 14 is provided with two trigger modes, one is manual trigger, namely, manual start of recording DIC images; the other is automatic triggering, and is connected with the temperature sensor 19, so that recording can be started after the temperature sensor 19 records a designated low temperature, and unnecessary image storage is reduced. The synchronous triggering of the cameras is always kept in the test stage, and the synchronous control precision is better than 0.01s.

Further, a positioning base plate 3 with adjustable height is arranged in the real-time low-temperature box 1, a rock sample 20 is arranged on the positioning base plate 3, and a base plate lifting control panel 4 is arranged on the real-time low-temperature box 1. The height of the positioning backing plate 3 is adjusted through the backing plate lifting control panel 4, so that rock samples 20 with different sizes can be always positioned at the center of the glass observation window 3 in the testing process.

Further, a light source control panel 6 is provided on the real-time cryogenic box 1. The light intensity of the light source 5 is adjusted by the light source control panel 6 to achieve the optimal three-dimensional DIC lighting effect.

Further, a fixing device 10 is arranged between the real-time low-temperature box and the temperature control box 8.

Further, the glass observation window 2 is arranged in a double-layer hollow mode, and double-layer sealant is arranged around the glass observation window 2. The air pressure tightness of the sealant is good, the refrigerating effect is guaranteed, and the possibility of fogging and dew condensation is reduced to a certain extent.

The working principle of the utility model is as follows: as shown in fig. 3, the rock sample 20 is placed in the real-time low-temperature box 1, the speckle paper and the temperature sensor 19 are attached to the surface of the rock sample 20, the temperature control box 8 controls the temperature of the real-time low-temperature box 1 to be reduced, the light source 5 is adjusted to achieve the optimal three-dimensional DIC lighting effect, the temperature sensor 19 collects temperature data, the synchronous camera trigger 14 is triggered manually or by temperature, the CCD camera 13 is controlled to collect DIC image data at the same time and transmit the DIC image data to the computer 16, and the computer 16 analyzes frost heaving deformation of the rock sample 20 at low temperature based on the temperature data and the DIC image data.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. 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 utility model. Thus, the present utility model 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. Real-time low temperature frost heaving deformation testing arrangement based on three-dimensional DIC, a serial communication port, including real-time low temperature test system, temperature calibration system and three-dimensional DIC monitoring system, real-time low temperature test system includes real-time low temperature case (1) and temperature control case (8), real-time low temperature case (1) set up temperature control case (8) top, be provided with rock sample (20) in real-time low temperature case (1), real-time low temperature case (1) openly is provided with glass observation window (2), rock sample (20) with glass observation window (2) are aligned, real-time low temperature case (1) is provided with adjustable light source (5) all around, temperature calibration system gathers the temperature data of rock sample (20), three-dimensional DIC monitoring system gathers the DIC image data of rock sample (20).

2. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing device according to claim 1, wherein a water inlet and outlet pipe (12) is arranged on the right side of the temperature control box (8), a water inlet and outlet valve (11) is arranged on the water inlet and outlet pipe (12), the temperature control box (8) is connected with the real-time low-temperature box (1) through the water inlet and outlet pipe (12), a water tank is arranged in the temperature control box (8), alcohol is arranged in the water tank, and the alcohol circularly flows in the real-time low-temperature box (1) and the temperature control box (8) through the water inlet and outlet pipe (12).

3. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing device according to claim 2, wherein the water inlet and outlet pipe (12) is a copper pipe, and the water inlet and outlet pipe (12) is wrapped with a heat-insulating sponge.

4. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing device according to claim 1, wherein a temperature control panel (9) is arranged on the surface of the temperature control box (8), a refrigerant, a compressor, a condenser and an evaporator are arranged in the temperature control box (8), and the compressor, the condenser and the evaporator are sequentially connected to form a circulation loop, and the refrigerant is arranged in the circulation loop.

5. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing apparatus according to claim 1, wherein the temperature calibration system comprises a temperature sensor (19), a temperature data acquisition line (17) and a temperature data acquisition instrument (18), the temperature sensor (19) is stuck on the rock sample (20), the temperature sensor (19) is connected with the temperature data acquisition line (17), and the temperature data acquisition line (17) is connected with the temperature data acquisition instrument (18) through a mounting hole (7) on the real-time low-temperature box (1).

6. The real-time low-temperature frost heaving deformation testing device based on the three-dimensional DIC according to claim 1, wherein the three-dimensional DIC monitoring system comprises speckle paper, two CCD cameras (13), a synchronous camera trigger instrument (14), a data transmission line (15) and a computer (16), the speckle paper is adhered to the surface of the rock sample (20), the two CCD cameras (13) are symmetrically arranged on two sides of the real-time low-temperature box (1), the CCD cameras (13) are connected with the synchronous camera trigger instrument (14) through the data transmission line (15), and the synchronous camera trigger instrument (14) is connected with the computer (16).

7. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing apparatus according to claim 1, wherein a positioning pad (3) with adjustable height is provided in the real-time low-temperature box (1), the rock sample (20) is provided on the positioning pad (3), and a pad lifting control panel (4) is provided on the real-time low-temperature box (1).

8. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing apparatus according to claim 1, wherein the real-time low-temperature box (1) is provided with a light source control panel (6).

9. The three-dimensional DIC based real-time low temperature frost heaving deformation test apparatus of claim 1, wherein a fixture (10) is provided between the real-time low temperature box and the temperature control box (8).

10. The three-dimensional DIC-based real-time low-temperature frost heaving deformation testing device according to claim 1, wherein the glass observation window (2) is arranged in a double-layer hollow mode, and double-layer sealant is arranged around the glass observation window (2).