Device and method for monitoring full-length stress of recoverable drill hole of coal body

Abstract

The invention provides a device and a method for monitoring full-length stress of a recoverable drill hole of a coal body, and relates to the technical field of mining engineering. The device comprises a plurality of monitoring units; each monitoring unit comprises a high-pressure bag body, a stress sensor, a high-pressure stress monitor, a one-way check valve, a pressure relief hydraulic valve, a data acquisition instrument and a pressure pump; the one-way check valves are arranged between the monitoring units and connected with the corresponding high-pressure bag bodies, and the high-pressure bag bodies are filled with stress transmission media; each high-pressure bag body is internally provided with one corresponding high-pressure stress monitor, the high-pressure stress monitor transmits monitoring parameters to the corresponding data acquisition instrument, and each pressure relief hydraulic valve is arranged at the connecting end of the corresponding high-pressure bag body. According to the method, multiple groups of stress monitoring devices are arranged in a roadway to monitor the stress change of a roadway coal body and determine a stress peak curve. The device can realize the full-length stress monitoring of the drill hole, is convenient to install, ensures the coupling of the drill hole and the stress meter, and is low in manufacturing cost.

Description

technical field [0001] The invention specifically relates to the technical field of mining engineering, in particular to a full-length stress monitoring device and a monitoring method for recoverable coal boreholes. Background technique [0002] As the mining depth of coal seams increases year by year, the prevention and control of coal mine rock burst accidents has become the focus of mine disaster prevention and control. According to the existing research, there is a close relationship between the rock burst load and the stress change of the coal body. Borehole stress monitoring and early warning is also one of the effective means for preventing and controlling rock burst disasters. Previously, there were often problems with early warning failures. Stress monitoring is an important means of stress assessment of coal and rock mass, monitoring and early warning of rock burst, and detection and evaluation of the effect of prevention and control measures. How to quickly, accu...

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Problems solved by technology

[0003] The current common mining stress monitoring method is the fluid-filled expansion pillow stress gauge. This type of stress gauge is limited by the structure of the oil bag and can only monitor the vertical stress. It has high requirements for on-site installation and can be installed when the direction of the principal stress cannot be determined. have a certain blindness

Drilling stress gauges are generally installed in Φ42mm boreholes. One strain gauge for each borehole can only measure the stress at one point of the hydraulic pillow of the stress gauge; the hydraulic pillow stress gauge requires a special drill pipe for installation. When the hole depth exceeds 10m, the installation angle is not easy to control, resulting in reduced monitoring accuracy or even installation failure. In addition, the hydraulic pillow type stress gauge may be pulled out under pressure, which brings wrong information to the on-site stress monitoring; the existing stress gauges mostly use rigid material, so the rigidity coupling with the surrounding rock of the borehole is poor, especially when installed in a borehole that is prone to collapse, it is difficult to meet the installation requirements, resulting in poor monitoring effect

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