A Numerical Simulation Study Of Surface Movement Law Of Coal Seam Underground Mining In Yushenfu Mining Area

The Yushenfu Mining Area in Northern Shaanxi is rich in coal resources.The coal seam is characterized by shallow burial and thin bedrock covering.It is a super large coal development base in China.However,due to the fragile ecological environment,complex terrain conditions,guly and transverse cutting,large-scale and high strength underground coal seam mining,the surface movement and deformation of the overlying strata caused by the overlying strata have its special laws,and have caused serious damage to the geological environment and the ecological environment of the mining area.This paper takes the N1206 mining face of Caragana pagoda minefield as a modeling prototype,and uses the UDEC discrete element numerical simulation software to simulate the movement of overlying rock,stress change and fracture development of the surface flat and different mining height,and the overlying rock displacement,stress change and fracture development after the coal mining under the conditions of different slope and mining direction.On the basis of the numerical simulation analysis,on the basis of the analysis of the real groove on the working face,on the one hand,the accuracy of the law is obtained.On the other hand,the variation law of the horizontal displacement of the two sides of the slope under different control measures is analyzed,and the effective method to control the occurrence of the geological disaster on both sides of the ditch is explored.The main research contents and conclusions are as follows:(1)Under the condition of surface flatness,the subsidence of the ground surface increases gradually with the increase of the mining height(4m to 8m),the accumulation of the caving belt on the roof is more broken,but the subsidence coefficient is basically unchanged,and the vertical displacement evolution law of the overlying rock is similar,which all experienced the changes of the arch,the high cap shape and the near rectangle,and the maximum ground surface under the height of 6m.The settlement is 4.327m and the subsidence coefficient is 0.721,which is consistent with the actual mining condition.Simulation analysis shows that the subsidence of surface subsidence and the main key stratum is consistent,and the lower part of the inferior key strata subsidence is large,consider that the main key stratum control surface subsidence effect is greater than the inferior key strata.(2)Under the conditions of different slope and mining direction,the maximum horizontal displacement on the slope is fixed,the average value is 2.039m,and the displacement increases gradually from the top of the slope to the foot of the slope,and the maximum displacement of the slope increases with the slope on the slope when the reverse slope is mined.The value position is closer to the top of the slope,the average value is 1.504m,the horizontal displacement produced by the slope mining on the slope is larger than the reverse slope mining,and the horizontal displacement of the reverse slope mining on the back side of the slope is much farther than that of the slope mining,and the displacement produced by the same position is greater.We concluded that the reverse direction than along the slope direction slope mining mining is more conducive to the stability of slope body,not prone to landslides and other geological disasters,and the slope direction compared to the inverse slope direction of mining mining can reduce the occurrence of cracks in the side slope.(3)When the surface gully is undulating,the horizontal displacement produced by the left and right sides of the slope is the same as that of the slope and the reverse slope.The displacement of the slope is the same as that in the direction of the slope and the reverse slope,and the regularity of the change of the slope displacement is the same.At the same time set different stop line position and pillar width control,slope displacement,the stop line position is not advance through the channel,the channel from the bottom level of the farther the distance,the slope is more stable;channel reserved coal pillar width increases,the slope is more stable.