Acoustic emission test equipment and analysis technology for rock breaking

Patent metadata

Field	Value
Publication number	US-11280762-B2
Application number	US-202016699130-A
Country	US
Kind code	B2
Filing date	Nov 29, 2019
Priority date	Nov 29, 2018
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A system for monitoring rock damage in deep engineering environment includes an acoustic emission sensor assembly and an acoustic emission amplifier assembly. The assemblies are mounted on a rock mechanics test system. The acoustic emission sensor clamp includes a coupling screw, as well as a clamp cover, a clamp cylinder, and a coupling panel threadedly connected in sequence. The acoustic emission amplifier assembly includes an acoustic emission amplifier, an upright column having a guide rail, a lifting support plate, and a support plate lifting oil cylinder. Additionally, an evaluation method based on acoustic emission tempo-spatial evolution laws is presented. According to the properties of acoustic emission, fractal characteristics of damage evolution processes of rock test pieces are analyzed and the relationship between stress, energy and fractal dimension in the whole process of tensile deformation damage of the rock test pieces is obtained.

First claim

What is claimed is:

1. A system for monitoring rock damage in a deep engineering environment, comprising an acoustic emission sensor assembly and an acoustic emission amplifier assembly; wherein
the acoustic emission sensor assembly and the acoustic emission amplifier assembly are mounted on a rock mechanics test system;
the rock mechanics test system comprises a triaxial cavity base, a triaxial cavity mounted on the triaxial cavity base, a triaxial cavity lifting oil cylinder mounted on a top of the triaxial cavity, an upright column mounted on an output end of the triaxial cavity lifting oil cylinder, and a test piece indenter arranged at the top of the triaxial cavity, and an indenter base arranged at a bottom in the triaxial cavity, between the test piece indenter and the indenter base there is space for placing a test piece, the test piece indenter is mounted on the output end of the triaxial cavity lifting oil cylinder through the upright column, and the triaxial cavity lifting oil cylinder drives the test piece indenter through the upright column to move up and down;
the acoustic emission sensor assembly comprises a plurality of acoustic emission detection heads and a clamp fixing spring; and each of the plurality of acoustic emission detection heads comprises an acoustic emission sensor and an acoustic emission sensor clamp mounted in one-to-one correspondence;
the acoustic emission sensor clamp comprises a coupling screw, a clamp cover, a clamp cylinder, and a coupling panel, and the clamp cover, the clamp cylinder and the coupling panel are threadedly connected in sequence; the clamp cover comprises a cover body provided with an internal thread, and a cover spring installed at a center of a bottom surface of an inner cavity of the cover body; two ends of a cylinder wall of the clamp cylinder are respectively provided with an external thread, and an end of the two ends of the cylinder wall is provided with an arc-shaped notch, and three cut-through coupling holes are evenly distributed on the cylinder wall along a circumferential direction, and three coupling screws pass through the three coupling holes ( 8 - 2 - 2 ) respectively to clamp the acoustic emission sensor in a radial direction of the clamp cylinder at a center of an inner cavity of the clamp cylinder; an upper surface of the coupling panel is flat and straight and is provided with a threaded through hole at a center of the upper surface, and a lower surface of the coupling panel is bent along a uniaxial direction and forms a cambered surface fitting with an outer surface of the cylinder wall of the clamp cylinder;
the triaxial cavity is further provided with two sets of the plurality of acoustic emission detection heads in positional correspondence with two ends of the test piece, one set of the two sets of the plurality of acoustic emission detection heads is composed of N acoustic emission detection heads uniformly distributed on the outer wall of the triaxial cavity along a circumferential direction and the clamp fixing spring connecting the N acoustic emission detection heads end to end to form a ring; two ends of the acoustic emission sensor are respectively connected to the clamp fixing spring extending into the acoustic emission detection heads from the arc-shaped notch, and the clamp fixing spring in a stretched state provides the acoustic emission sensor with a pressure urging the acoustic emission detection heads to stably fit with the outer wall of the triaxial cavity, wherein N is a positive integer greater than 1; and
the acoustic emission amplifier assembly comprises an acoustic emission amplifier, an upright column having a guide rail, a lifting support plate, and a support plate lifting oil cylinder, wherein an output end of the support plate lifting oil cylinder mounted on the triaxial cavity base arranged transversely, two upright columns having guide rails vertically fixed to the triaxial cavity base are slidably connected to two ends of the lifting support plate, respectively, the acoustic emission amplifier connected to the acoustic emission sensor in one-to-one correspondence is mounted on the lifting support plate far away from the triaxial cavity, and the acoustic emission amplifier sends an amplified signal to the acoustic emission sensor via a signal line passing through the arc-shaped notch.

2. The system for monitoring rock damage in the deep engineering environment according to claim 1 , wherein the clamp cylinder comprises an outer metal cylinder, an inner heat insulation cylinder, and a condenser pipe, between the outer metal cylinder and the inner heat insulation cylinder coaxially sleeved there is formed a condensation cavity communicating with the condenser pipe and allowing a condensate to be introduced.

3. The system for monitoring rock damage in the deep engineering environment according to claim 2 , wherein a value of the N is 4, there are eight acoustic emission detection heads in the two sets, and eight acoustic emission sensors of the eight acoustic emission detection heads are separately connected to eight acoustic emission amplifiers in one-to-one correspondence.

4. The system for monitoring rock damage in the deep engineering environment according to claim 1 , wherein a groove is respectively arranged at edges adjacent to a left side and a right side on the upper surface of the coupling panel, and two small-diameter circular holes are provided outside the groove.

5. The system for monitoring rock damage in the deep engineering environment according to claim 4 , wherein a value of the N is 4, there are eight acoustic emission detection heads in the two sets, and eight acoustic emission sensors of the eight acoustic emission detection heads are separately connected to eight acoustic emission amplifiers in one-to-one correspondence.

6. The system for monitoring rock damage in the deep engineering environment according to claim 1 , wherein the two ends of the acoustic emission sensor are respectively provided with a small hole allowing a connector of the clamp fixing spring to pass through; two adjacent acoustic emission sensors are directly connected through one clamp fixing spring, or two adjacent acoustic emission sensors are connected through a plurality of clamp fixing springs ( 7 ) connected in series.

7. The system for monitoring rock damage in the deep engineering environment according to claim 6 , wherein a value of the N is 4, there are eight acoustic emission detection heads in the two sets, and eight acoustic emission sensors of the eight acoustic emission detection heads are separately connected to eight acoustic emission amplifiers in one-to-one correspondence.

8. The system for monitoring rock damage in the deep engineering environment according to claim 1 , wherein an upper end of the upright column having the guide rail is provided with a linear guide rail, and two ends of the lifting support plate are respectively mounted with a pulley embedded into the linear guide rail and linearly slidable along the linear guide rail.

9. The system for monitoring rock damage in the deep engineering environment according to claim 8 , wherein a value of the N is 4, there are eight acoustic emission detection heads in the two sets, and eight acoustic emission sensors of the eight acoustic emission detection heads are separately connected to eight acoustic emission amplifiers in one-to-one correspondence.

10. The system for monitoring rock damage in the deep engineering environment according to claim 1 , wherein a value of the N is 4, there are eight acoustic emission detection heads in the two sets, and eight acoustic emission sensors of the eight acoustic emission detection heads are separately connected to eight acoustic em

Assignees

• Univ Sichuan
• Univ Chengdu

Inventors

• Xu Huining
• Liu Jianfeng
• Wan Yan
• Pei Jianliang
• Wang Lu
• Wang Chunping
• Zhang Qiangxing

Classifications

• G01N3/08

  by applying steady tensile or compressive forces (G01N3/28 takes precedence) · CPC title

• G01N2203/0048

  Hydraulic means · CPC title

• G01N29/227

  related to high pressure, tension or stress conditions · CPC title

• G01N2203/0226

  High temperature; Heating means · CPC title

• G01N29/223 Primary

  Supports, positioning or alignment in fixed situation (mounting transducers per se G10K11/004) · CPC title