深厚冲积层薄基岩条件下沿空留巷支护技术研究

Study on Support Technology of Gob-side Entry Retaining under Condition of Thick Alluvium and Thin Bedrock

为解决某矿16041工作面原支护方案沿空留巷变形大、破坏严重难题,提出了顶板采用“16#槽钢梁+注浆锚索”、采空区侧采用“36U型钢+注浆锚杆”不对称耦合支护优化方案,基于理论分析研究围岩结构破坏形式,通过单元荷载法计算了留巷顶板与采空区侧围岩应力,最后开展工业性应用,验证优化后方案的合理性。研究表明:优化后支护方案顶板和采空区侧计算单元面荷载分别为351.85 kPa和206.53 kPa;注浆锚索和注浆锚杆承载力分别为263.89 kN和199.08 kN,均小于注浆锚索(锚杆)极限承载力。根据对留巷数据监测,最大顶板下沉量为35.6 mm,较原支护方案减小了1.40倍;采空区侧最大移近量为29.6 mm,与较原支护方案减小了4.13倍;最大注浆锚索承载力为253 kN,与理论计算值误差为4.1%;最大注浆锚杆承载力为174 kN,与理论计算值误差为12.6%。位移量与支护承载力均在工程允许范围内,优化后方案支护效果良好。

In order to solve the problem of large deformation and serious damage of the original support scheme for the retaining roadway along the goaf in the 16041 working face of a certain mine,an optimization scheme of asymmetric coupling support using"No.16 channel steel beam grouting anchor cable"for the roof and"36U-type steel grouting anchor"for the goaf side was proposed.Based on theoretical analysis,the failure form of the surrounding rock structure was studied,and the stress of the retaining roadway roof and the goaf side was calculated using the unit load method.Finally,industrial application was carried out,verify the rationality of the optimization scheme.The research shows that the calculated unit area loads on the roof and goaf sides of the optimized support scheme are 351.85 kPa and 206.53 kPa respectively;the bearing capacity of grouted anchor cable and grouted anchor bolt is 263.89 kN and 199.08 kN respectively,which are both less than the ultimate bearing capacity of grouted anchor cable(bolt).According to the monitoring of the remaining roadway data,the maximum roof subsidence is 35.6 mm,which is 1.40 times less than the displacement of the original support scheme;the maximum displacement at the goaf side is 29.6 mm,which is 4.13 times smaller than the original support scheme;the maximum grouting anchor cable bearing capacity is 253 kN,with an error of 4.1%from the theoretical calculation value;the maximum grouting anchor bearing capacity is 174 kN,with an error of 12.6%from the theoretical calculation value.The displacement deformation and support bearing capacity are within the allowable range of the project,indicating that the optimized scheme has a good support effect.