破碎覆岩回采巷道临界宽度研究

Research on Roadway Critical Width of Crushing Overburden

为有效控制破碎覆岩回采巷道变形,根据其赋存特征采用"工"字钢架棚支护技术,分析破碎覆岩普氏拱结构的形成原理和研究回采巷道临界宽度。针对破碎覆岩回采巷道围岩松碎、强度低和不具有可锚性等特点,采用普氏拱理论,计算回采巷道围岩压力;当棚梁"工"字钢最大正应力等于"工"字钢屈服极限时推导出破碎覆岩条件下回采巷道临界宽度计算公式。以106煤矿为工程实例进行分析,结果表明:破碎覆岩回采巷道的合理临界宽度为4.4 m;增大支护强度和减小巷道高度可有效提高破碎覆岩回采巷道临界宽度;如果需要更大的巷道宽度,可通过降低棚间距或增大型钢型号方法实现。

In order to control the deformation of roadway with crushing overlying strata effectively,the support technology of joist steel shed was used according to the overburden rock characteristics. The forming principle of arch structure was analyzed and the critical width of roadway was determined. Aiming at the characteristics of the roadway with its surrounding rock crushing,low strength,anchorless,the equilibrium arc theory was applied to calculate the surrounding rock pressure. The critical width formula was built when the maximum principal stress of steel shed beam was equal to joist steel yield limit. The 106 coal mine taken as an engineering example was analyzed. The results showed that the critical width of roadway was 4. 4 m. The roadway critical width could be improved by increasing the supporting strength or reducing the roadway height. The method of reducing shed distance or increasing the steel type could be used to realize the greater roadway width.