Research On Laws Of Underground Pressure In4^-2101Fully-mechanized Caving Face Of Jian Bei Coal Mine

Jianbei coal mine is the new coal which is located in the northern of HuanglingJianzhuang mining area that is in Yanan city Shaanxi Province. The main coal seam is4-2coalseam, thickness of coal seam is5～10m, the average thickness is7.6m, buried depth is473～570m, the elevation is827～920m, the angle is2～5°, design capacity is2100000t/a. Thispaper uses the Jianbei coal mine’s geological conditions as the background, on the basis ofmine pressure observation data, using the method of computer numerical simulation andtheoretical analysis to4-2101fully mechanized face mine pressure regularity are studied.It studied that the basic roof’s initial pressure pace of4-2101workingface is25m and theperiodic pressure pace is9.6～15.7m, the average pace is12.5m. Basic roof support on thedynamic load coefficient is1.2～1.7, on average is1.5, each stage to compressive strength isnot high, there are obvious periodic pressure and roof management difficulty of medium.Constriction of entry was beyond workingface about35m, the range of roof and floor closerfaster at6～15m, small amounts of cumulative nearer, the maximum of30.47mm, thesupporting method is safe. Stoping less disturbance on the roadway, the peak of abutmentpressure was from4to10m in front of coal wall, influence range is within the scope ofworking face in front of the35m; According to RFPA numerical simulation research, withinitial and periodic working face advancing to16m direct roof caving for the first time, paceof initial and periodical pressure were separately25m and12.4m, basic consistent, theoreticalanalysis and field testing. The fourth,second and sixth floors separately are key layer and subcritical layer in the overlying strata structure, direct roof belongs to the class2medium stableroof, cyclical crushing properties of basic roof is Ⅱ soft easy caving roof.4-2101workingface as initial mining full-mechanized caving face in Jianbei coal mine and build the law ofroof movement and mining pressure regularity has certain representativeness, therefore graspmine pressure regularity of full-mechanized caving mining face for mine safety and high yieldand high efficiency is of great realistic significance.