CN105841860A - Quantum dot crustal stress testing device, and preparation method and using method thereof - Google Patents

Abstract

The invention discloses an in-situ stress test device, preparation method and application method of quantum dots. The test device includes a natural rubber cylinder (1), and the top surface (3) of the natural rubber cylinder is provided with a micro For the crack (4), the surface layer of the top surface (3) is coated with a quantum dot epoxy resin film (2). The preparation method is as follows: after mixing the epoxy resin and the curing agent, adding quantum dots dissolved in chloroform, coating the quantum dot epoxy resin on the top surface of the natural rubber cylinder, and drying in vacuum for more than 5 hours. The method of use is that the test device is placed in the borehole and grouted, the top surface of the test device is flush with the rock mass; the surface cracks on the top surface of the test device are photographed with an on-site photographic microscope; Fluorescence intensity signals at cracks and non-cracks are collected; the relationship between crack variation and stress is obtained through computer calculation. The invention has the advantages that it can be used repeatedly and the measurement accuracy is significantly improved.

Description

An in-situ stress testing device, preparation method and use method of quantum dots

technical field

The invention belongs to the technical field of geotechnical engineering pressure testing, and in particular relates to a quantum dot ground stress testing device, a preparation method and a method for using the device to implement ground stress testing.

Background technique

In-situ stress is the fundamental force that causes the deformation and destruction of underground engineering rock mass. Accurately obtaining the in-situ stress vector value is the key to determining the mechanical properties of engineering rock mass, analyzing the stability of surrounding rock, and realizing the scientific decision-making and design of excavation and support in underground engineering. Necessary prerequisite.

At present, there are many methods for testing in-situ stress at home and abroad, such as hydraulic fracturing method, stress relief method, acoustic emission method, flat jack method, BWSRM method, etc. However, due to limitations in accuracy, scope of application, and the particularity of engineering rock mass, the most commonly used in-situ stress testing methods in engineering practice are mainly hydraulic fracturing and stress relief methods. The hydraulic fracturing method mainly isolates a small section of the borehole in the borehole, injects water into the isolated section, and determines the ground stress through the swelling and cracking of the rock mass on the wall of the hole. The stress relief method is mainly to release the stress, deform the rock core, and determine the in-situ stress by measuring the strain. However, these methods have problems such as non-repeatability and low accuracy of measurement data.

Contents of the invention

Aiming at the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a quantum dot geostress testing device, which can be used repeatedly for testing and can improve the accuracy of measurement data. A method of making the device is also provided. Furthermore, a method for using the testing device to perform ground stress testing is provided, which can obtain measurement data more intuitively and conveniently, and the collected data is also more refined.

In order to solve the above-mentioned technical problems, a kind of ground stress testing device of quantum dot provided by the present invention comprises a natural rubber cylinder, and the top surface of the natural rubber cylinder is provided with a microcrack of known width, and the natural rubber cylinder The surface layer of the top surface is coated with a quantum dot epoxy resin film.

The preparation method of a kind of above-mentioned device provided by the present invention: after epoxy resin and curing agent are mixed, then add the quantum dot dissolved in chloroform, obtain quantum dot epoxy resin after stirring, apply quantum dot epoxy resin on natural The top surface of the rubber cylinder was vacuum dried for more than 5 hours.

Provided by the present invention is a method for using the above-mentioned test device to implement an in-situ stress test, comprising the following steps:

Step 1. Drill holes at the points to be measured in the rock mass, and clean the walls of the holes;

Step 2, place the above test device in the borehole and inject grout, the top surface of the test device is flush with the rock mass;

Step 3, irradiate the quantum dot epoxy resin film on the top surface of the test device with an ultraviolet light irradiation lamp, and use a high-precision on-site photographic microscope to take pictures of the surface cracks on the top surface of the test device; Fluorescence intensity signals at non-cracks;

Step 4. Transmit all the collected photos and fluorescence intensity signals to the computer, and process the data to accurately measure the surface crack width;

Step 5. According to the variation of the crack width, the above-mentioned test device is calibrated through indoor true triaxial experiments, and combined with theoretical derivation and numerical simulation, the relationship between the crack variation and stress is obtained through computer calculation.

Because the test device of the present invention is made of natural rubber, it has good elasticity and high strength, and the microcracks made on the top surface surface will expand after the device is compressed. After the device has been placed for a period of time, the width of the crack is determined using an on-site photographic microscope and a portable fiber optic spectrometer, and then the data is transmitted to the computer, and the magnitude of the ground stress is obtained through the calculation software. After testing the ground stress at this point, the device can be taken out, because natural rubber has good elasticity, and the extended cracks can be restored to the original state after the device is taken out, and the device can be reused.

The quantum dot epoxy resin is coated on the top surface of the device to form a quantum dot epoxy resin film, and the quantum dot epoxy resin film is irradiated with an ultraviolet light lamp, and the quantum dots generate fluorescence, and then the fluorescent image is received by the probe of the portable fiber optic spectrometer. Stored in a portable fiber optic spectrometer. As the crack expands, the fluorescence of the quantum dot epoxy resin film will increase, and the fluorescence intensity at the crack is significantly different from that at the non-crack. The surface cracks on the top surface of the device are photographed and measured with an on-site photographic microscope, and the measurement accuracy can reach μm; at the same time, a portable fiber optic spectrometer is used to collect the fluorescence intensity signals at the cracks and non-cracks on the top surface of the device, and the cracks are accurately obtained by analyzing the fluorescence intensity. width. Therefore, the on-site photographic microscope is used in combination with the portable fiber optic spectrometer to more accurately obtain the variation of surface cracks on the top surface of the test device.

The present invention adopts natural rubber, a material with high elasticity and high strength, as the force-receiving body, so that the cracks of the device can expand after being stressed, and the device can be reused at the same time. The use of quantum dot epoxy resin film can make accurate measurement of the change of cracks in μm level, and improve the measurement accuracy. Compared with the prior art, the invention has the advantages that it can be used repeatedly and the measurement accuracy is significantly improved.

Description of drawings

The accompanying drawings of the present invention are as follows:

Fig. 1 is the structural representation of test device of the present invention;

Fig. 2 is a schematic diagram of installation and use of the test device of the present invention.

In the figure: 1. Natural rubber cylinder; 2. Quantum dot epoxy resin film; 3. Top surface; 4. Microcrack; 5. Portable fiber optic spectrometer; 6. Field photographic microscope; 7. Ultraviolet light irradiation lamp; 8. Drilling; 9. Grouting.

detailed description

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

As shown in Figure 1, device of the present invention comprises natural rubber cylinder 1, and the top surface 3 of natural rubber cylinder is provided with a microcrack 4 of known width, is coated with on the surface layer of the top surface 3 of natural rubber cylinder Quantum dot epoxy resin film2.

The preparation method of the device of the present invention is: after the epoxy resin is mixed with the curing agent, then add the quantum dots dissolved in chloroform after washing, apply the stirred quantum dot epoxy resin on the top surface of the natural rubber cylinder, vacuum Dry for more than 5 hours.

As shown in Figure 2, use the test device of the present invention to implement the method for ground stress test, comprising the following steps:

Step 1. Drill holes at the points to be measured in the rock mass, and clean the walls of the holes;

Step 2, placing the above-mentioned test device in the borehole 8, there is a grouting 9 between the test device of the present invention and the gap between the borehole 8, and the top surface of the device is flush with the rock mass;

Step 3, irradiate the quantum dot epoxy resin film on the top surface of the test device with an ultraviolet light irradiation lamp 7, and use a high-precision on-site photographic microscope 6 to take pictures of the surface cracks on the top surface of the test device; Fluorescence intensity signals at cracks and non-cracks;

Step 4. Transmit all the collected photos and fluorescence intensity signals to the computer, and process the data to accurately measure the surface crack width;

Step 5. According to the variation of the crack width, the above-mentioned test device is calibrated through indoor true triaxial experiments, and combined with theoretical derivation and numerical simulation, the relationship between the crack variation and stress is obtained through computer calculation.

The principle of the calibration experiment is the same as that of the Brazilian disc experiment. Firstly, micro-cracks are set on the sample, and then loaded to failure through the loading device to obtain the stress-crack change curve of the crack, so as to obtain the relationship between the crack width and the stress.

Claims (3)

1. the detecting earth stress device of a quantum dot, it is characterized in that: include natural rubber cylinder (1), the cylindrical end face of natural rubber (3) is provided with the micro-crack (4) of a known width, scribbles quantum dot epoxy resin film (2) on the top layer of the cylindrical end face of natural rubber (3).

2. prepare the method testing device described in claim 1 for one kind, it is characterized in that: after epoxy resin mixes with firming agent, add the quantum dot being dissolved in chloroform, quantum dot ring epoxy resins is obtained after agitated, quantum dot ring epoxy resins is coated in the cylindrical end face of natural rubber, is vacuum dried more than 5 hours.

3. use the method that device implements detecting earth stress of testing described in claim 1, it is characterized in that, comprise the following steps:

Step 1, boring at rock mass tested point, and hole wall is cleared up；

Step 2, being placed in boring by described test device and slip casting, the end face of test device is concordant with rock mass；

Step 3, use ultraviolet lighting shot-light irradiate the quantum dot epoxy resin thin film of test device end face, and use high-precision On-site photo microscope to take pictures the top layer crackle of test device end face；Use the fluorescence intensity signals of portable fiber-optic spectrometer collection in worksite cracks and non-cracks simultaneously；

Step 4, the photo of all collections and fluorescence intensity signals are transmitted to computer, by these data are processed, accurately measure top layer crack width；

Step 5, variable quantity according to crack width, by described test device by indoor true triaxial experimental calibration, and binding isotherm is derived and numerical simulation, draws the relational expression between crackle variable quantity and stress by Computing.