Study On The Mining Pressure Law And Support Resistance Under The Shallow Coal Seam Trench

The topography of the shallow coal seam in the Yushenbei mining area is generally gully-like.The mining pressure law of the coal seam under the terrain is different from that of the shallow coal seam in the general non-gully area.The hydraulic support on the working face is prone to crushing" phenomenon,which will cause certain safety hazards to the safe production of the working face.Based on this,this paper takes the mining of 1-2 coal face in Nanliang Coal Mine,which belongs to China Coal Energy,as the engineering research background,and uses the theoretical analysis,numerical simulation,physical similarity simulation and machine for the mining conditions of shallow buried coal seam under the mine landform By studying research methods such as prediction,the movement of overburden rock and the selection of support resistance in shallow coal seam mining under the gully are studied.The main research results are as follows:(1)Through theoretical analysis,it is concluded that the first mining pressure step of the Nanliang 1-2 coal working face is 30.76m,the periodic pressing pressure step is 12.55m,and the mining step is over the shallower valley when the mining step is uphill.It is 9.7m,the support resistance is 7208.75kN,the mining pressure step distance is 8.7m in the uphill section of the deep valley,the support resistance is 7549.373kN,the support resistance in the non-ditch valley mining area is 7259.96kN,and the support resistance in the shallow trench is 7459.43kN.The support resistance of mining in deep valleys is 8551.44kN,The mining pressure of mining face with different valley depth and along and under slope is also different.(2)Through similar simulation and numerical simulation,it can be seen that the disturbance of slope mining on the working face leads to the rotation of the key layer,the tensile failure of the slope occurs,and the fissure develops to the surface.When the working face is mining uphill in shallow valleys,the period pressure step is 10.5m,the simulated hydraulic support reading is(?)is mining uphill deep valleys,the period comes The pressure step is 9.5m,the simulated hydraulic support reading is 7533.4kN,and the roof stress is 2.1MPa.The resistance of mining support in shallow valleys is 7459.43kN,the stress of mining roof is 1.9MP,the resistance of mining support in deep valleys is 8345.55kN,the stress of mining roof is 3MPa,and the resistance of mining support in non-ditch valley is 7259.96kN.The stress of the roof of the stope is 1.9MPa,and the law of mine pressure is basically consistent with the theoretical analysis.(3)According to the geological and geomorphological characteristics of shallow buried coal seam in Nanliang 1-2 coal seam valley,the relevant data was collected and the support resistance prediction software for the mining face at the bottom of the trench was written by python.At the same time,the improved Logistic Stochastic Algorithm(LR)is used to optimize the gradient lifting regression(GBRT)model.The prediction model is applied to the prediction of hydraulic support resistance,and the prediction results are compared with LR(linear regression model),SVM(support vector machine model),DTR(decision tree regression model)EN(elastic network regression model).The results show that the LR-GBRT model has higher generalization ability and smaller prediction error,and can effectively predict the resistance of hydraulic support mining under the Nanliang 1-2 coal ditch valley.Good reference value.