A prevention technology of rock burst based on directional presplitting of water jet prefabricated slot in hard roof#br#
PAN Junfeng1，2，3，MA Wentao1，2，3，LIU Shaohong1，2，3，GAO Jiaming1，2，3
(1. CCTEG Coal Mining Research Institute，Beijing 100013，China；2. State Key Laboratory of Coal Ming and Clean Utilization，CCRI，Beijing 100013，China；3. Coal Mining and Designing Department，Tiandi Science and Technology Co.，Ltd.，Beijing 100013，China)
Abstract：Most of rock bursts in China are closely related to the hard roof overlying coal seams. In order to improve the effect of presplitting and pressure relief of the hard roof，a directional presplitting and pressure relief method of water jet prefabricated slot of the hard roof was proposed. Aiming at a sandstone roof，the rock was cut by high pressure water jet in the laboratory，and the characteristic index values of the fracture groove，such as the depth，the width and the erosion volume of the rock under different hydraulic parameters，were measured. The field test was also carried out. The results show that the depth，the width and the erosion volume of rock slot characteristic indexes are positively correlated with the jet pressure，the nozzle diameter and the repeated cutting times，while negatively correlated with the transverse velocity of the nozzle. The characteristic index of the rock slot first increases and then decreases with increasing the target distance，and the optimal target distance is 5d. In the four level orthogonal experiment，five key factors affecting the optimization of pressure relief of the seam slot are the nozzle moving speed，the repeated cutting times，the jet pressure，the nozzle diameter and the target distance. Through selecting parameters based on the laboratory research rules，the underground experimental research on high-pressure water jet cutting of a roof was carried out. It is revealed that，for the roof rock with an uniaxial compressive strength of 68 MPa，the cutting radius is 10 times higher than that of the traditional cutting tool and the fracture initiation pressure is reduced. Under the guidance of the energy accumulation of the roof rock water jet prefabricated joint，the maximum single fracturing radius can reach 15 m，and the effect of anti-impact and pressure relief is good.
潘俊锋1，2，3，马文涛1，2，3，刘少虹1，2，3，高家明1，2，3. 坚硬顶板水射流预制缝槽定向预裂防冲技术试验[J]. 岩石力学与工程学报, 2021, 40(8): 1591-1602.
PAN Junfeng1，2，3，MA Wentao1，2，3，LIU Shaohong1，2，3，GAO Jiaming1，2，3. A prevention technology of rock burst based on directional presplitting of water jet prefabricated slot in hard roof#br#. , 2021, 40(8): 1591-1602.
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2021, Vol. 40 
