Research on rock burst prevention and control technology of steep extra-thick coal seam

Abstract

In order to study the prevention and control effect of the emergency relief measures of water injection before blasting on the sharp inclined ultra-thick coal seam, the south mining area of Wudong Coal Mine in Urumqi Mining area of China was taken as the research object. Based on the special geological conditions of the mine field, the methods of field investigation, theoretical analysis, numerical simulation and field test were comprehensively applied. This paper analyzes the change law of stress distribution of rock pillar in the middle of steep extra-thick coal seam with the increase of mining depth, and puts forward a technology of pre-cracking blasting to relieve pressure of rock pillar by building construction chamber in the middle of rock pillar, so as to form buffer layer in rock wall and prevent stress from moving down effectively. The optimum blasting hole spacing is determined by combining the theoretical calculation and numerical simulation results with the field test. The results show that there is little difference between the theoretical calculated hole spacing and the simulated one, and the hole spacing can be increased from 8 m to 10 m by using the rock burst control scheme of water injection before blasting. The EH-4 high-resolution electromagnetic imaging system and Terra TEM subsurface transient electromagnetic instrument were used to detect the spatial structure of overlying rock before and after blasting, and it was confirmed that the pressure relief effect of surface blasting and underground blasting was obvious. The research results are of guiding significance for relieving pressure and preventing scour of rock pillars between coal seams in Wudong mine field, and provide reference for the selection of other mine blasting relieving pressure schemes under similar conditions.