回坡底煤矿工作面运输巷复合型底鼓机理研究

Study on mechanism of compound floor heave in transport roadway of working face in Huipodi Coal Mine

以回坡底煤矿11-1021工作面运输巷为研究对象。利用半平面无限体理论对11-1021巷上方10号煤层孤岛煤柱对底板岩层的应力集中进行了研究。根据11-1021巷底板岩层的实际情况,发现11-1021巷的底鼓类型为挠曲褶皱性+挤压流动性的复合性底鼓,其底鼓机理较为复杂,对11-1021巷的复合型底鼓进行了具体分析。研究结果表明:孤岛煤柱造成的应力集中使得11-1021巷的水平应力达到19.6 MPa,较大的水平应力作用是巷道发生底鼓现象的原因之一。对于11-1021巷直接底的0.8 m铝质泥岩底板,根据压杆稳定理论得到失稳的临界应力为17 MPa,因此直接底会发生失稳鼓起。而对于11-1021巷厚度较大的基本底,利用滑移线理论计算得两帮处的支承压力峰值超过了底板岩层的极限承载力,会产生挤压流动性底鼓。同时,靠近孤岛煤柱一侧的支承压力峰值更大,在底板会形成较大区域的滑移线场,从而使巷道底鼓出现非对称性,并在远离孤岛煤柱一侧的底鼓量更大。

Taking the transportation roadway of 11-1021 working face in Huipodi Coal Mine as the research object.Based on the theory of semi-plane infinite body,the stress concentration of No.10 isolated coal pillar on floor rock above 11-1021 roadway was studied.According to the actual situation of floor rock strata in 11-1021 roadway,it was found that the floor heave type of 11-1021 roadway was a composite floor heave with flexural folding and extrusion fluidity,and the mechanism of floor heave was more complex,this paper made a concrete analysis of the compound bottom drum of 11-1021 lane.The results show that the stress concentration caused by the isolated coal pillar makes the horizontal stress of 11-1021 roadway reaches 19.6 MPa,and the larger horizontal stress is one of the causes of floor heave.For the 0.8 m aluminum mudstone floor of the direct bottom of 11-1021 roadway,according to the pressure bar stability theory,the critical stress of instability is 17 MPa,so the direct bottom will be unstable and bulge.For the base bottom of 11-1021 roadway with large thickness,the peak value of the supporting pressure at the two sides calculated by the slip line theory exceeds the ultimate bearing capacity of the floor rock stratum,which will result in an extrusion flow floor heave,at the same time,the peak value of the supporting pressure on the side near the isolated coal pillar is larger,and a large area of slip line field will be formed on the floor,so that the tunnel floor heave is asymmetric,and the floor heave on the side far away from the isolated coal pillar is larger.