不同刚度充填体采场应力分布及覆岩移动规律

Stress distribution of stope and movement law of overlying rock for filling bodies with different stiffness

为研究不同充填体刚度对采煤工作面围岩稳定性的影响,采用PHASE 2D有限元软件建立数值模拟,对充填体不同刚度条件下采场垂直应力及覆岩垂直位移进行了研究,分析了工作面前后方支承压力分布特征、采场围岩下沉量等。研究结果表明,当充填体弹性模量为2000 MPa时,煤体塑性区宽度为1.98 m;当充填体弹性模量增大到3000 MPa、4000 MPa时,煤体塑性区宽度降低为1.5 m;当充填体弹性模量为2000 MPa时,工作面前方煤体支承压力系数峰值为1.8;当充填体弹性模量为3000 MPa、4000 MPa时,支承压力系数峰值分别为1.71和1.67;模型工作面推进200 m后,当弹性模量为2000 MPa时,直接顶下沉量最大值为20 mm,当弹性模量为3000 MPa、4000 MPa时,直接顶下沉量最大值为17 mm;随着充填体刚度不断增大,垂直位移随着弹性模量增大而逐渐减小,垂直位移最大值分别为45 mm、40 mm、37 mm。分析认为,提高充填体刚度能够降低煤体破坏范围和提高围岩稳定性,但随着充填体刚度的进一步提升,这一趋势不再明显。

To study the influence of filling bodies with different stiffness on the stability of surrounding rock in coal mining face,the numerical model was established by PHASE 2D finite element software,the vertical stress of stope and vertical displacement of overlying rock under different stiffness of filling bodies were studied,and the distribution characteristics of support pressure at the front and rear of the working face and the subsidence of surrounding rock in the stope are analyzed.The research results show that when the elastic modulus of the filling body is 2000 MPa,the width of the coal mass plastic zone is 1.98 m;when the elastic modulus of the filling body increases to 3000 MPa and 4000 MPa,the width of the coal mass plastic zone is reduced to 1.5 m;when the elastic modulus of the filling body is 2000 MPa,the peak value of the bearing pressure coefficient of the coal mass in front of the working face is 1.8;when the elastic modulus of the filling body is 3000 and 4000 MPa,the peak value of the bearing pressure coefficient is 1.71 and 1.67,respectively;after the model working face is advanced by 200 m,when the elastic modulus is 2000 MPa,the maximum value of the direct roof subsidence is 20 mm,and when the elastic modulus is 3000 MPa and 4000 MPa,the maximum value of the direct roof subsidence is 17 mm;with the stiffness of the filling body increases,and the vertical displacement gradually decreases with the increase of the elastic modulus,and the maximum vertical displacement is 45 mm,40 mm,and 37 mm.The analysis shows that increasing the stiffness of the filling body can reduce the damage range of the coal mass and improve the stability of the surrounding rock,but with the further improvement of the stiffness of the filling body,this trend is no longer obvious.