Three Dimensional In-situ Stress Real-time Measurement Technology And Its Application In Shoushan Mining Area

In recent years,due to the increasing depletion of shallow coal resources,the mining depth and intensity of coal mines will continue to increase,resulting in more and more high stress problems.The in-situ stress plays an important role in the safe mining of coal mine.The support design of underground tunnel,the impact of ground pressure and the disasters such as coal and gas outburst are closely related to in-situ stress.It is the basic work to accurately obtain the stress field characteristics in the mining area to avoid the occurrence of coal and rock dynamic disasters.Therefore,the research on real-time measurement technology of in-situ stress has practical significance for coal mine safety production.Based on this background,the stress sensing performance of the three-dimensional stress sensor is tested and analyzed,and the three-dimensional in-situ stress calculation formula is derived.The ground stress test was carried out at Shoushan No.1 Coal Mine of Pingbao Company in Henan Province.Finally,given high outburst risk during deep coal mining in the mine,the role of ground stress in coal and gas outburst was explored based on its unique geological structure.The main results and conclusions are as follows:(1)The experiment on stress sensing performance of the three-dimensional stress measurement device shows that the stress measured by the sensor can reflect the real load stress.In addition,the sensing spring plates are independent from each other,so as to meet actual engineering demand.The size and direction of principal stress of a point in space can be measured and figured out by a test unit formed by two self-built threedimensional stress sensors.The method is simple and easy to operate.(2)According to field measurement with the three-dimensional stress measurement device,the stress field of Shoushan No.1 Coal Mine belongs to a typical tectonic stress field where the horizontal principal stress predominates.The maximum horizontal principal stress is 22.86 MPa;the azimuth is 140°;and the dip angle is 2°.The results are consistent with previous research,results,indicating that the device can accurately realize the on-site measurement of ground stress.(3)The syncline axis is easy to form high stress and high gas pressure area.Under this environment,the gas-making coal is more prone to coal and gas outburst.The characteristics of in-situ stress field in Shoushan mining area play an important role in the occurrence and development of coal and gas outburst.Ground stress is not only an important factor influencing and changing the properties of gas-bearing coal seam,but also the core factor that induces coal and gas outburst.The research shows that the stress monitoring system can not only measure the insitu stress,but also quantitatively determine the dynamic change of the coal stress during the mining process,so as to realize the synchronous on-line monitoring of the three-dimensional stress of the coal body.The test results will be of great value to the prevention of coal and gas outburst in Shoushan mining area and the safe and efficient production of the deep mine.This paper consists of 24 figures,7 tables and 98 references.