动载作用下巷道超前支护区域划分

Division of advanced support areas in roadways under dynamic loads

巷道超前支护区域划分和支护方式是影响回采巷道围岩稳定性的关键因素。现有研究大多在静载条件下对超前支护区域进行划分,对于动载冲击作用下的超前支护区域划分及巷道围岩与液压支架之间的关系需进一步探讨。以赵楼煤矿5304工作面巷道为研究对象,分析了液压支架受动载冲击时工作阻力的变化特征及围岩与液压支架的关系,提出了动态系数概念。在动载扰动作用下,超前支承压力峰值点向煤体内部转移,将会产生新的塑性区,因此将超前支承压力影响区划分为破裂区、塑性区、弹性区、原岩应力区、新增塑性区。根据煤岩状态及动态分界点,以动态应力为界限将超前支护区域划分为加强支护段、辅助支护段和原始支护段:加强支护段由破裂区、塑性区和部分弹性区构成,需要较高强度超前支护设备加强顶板支护;辅助支护段主要以弹性区为主,需要单体液压支柱或单元式液压支架辅助支护;原始支护段整体处于原岩应力区,不需要加强支护。运用数值模拟研究了动载作用下超前支承压力变化规律,建立了动载作用下巷道超前支承压力计算模型,推导出各支护段动态应力表达式。现场实测结果表明,根据巷道超前支护区域划分结果设计的支护方案支护效果良好,可满足超前支护区域支护质量要求。

The division of advanced support areas and support methods in roadways are key factors affecting the stability of surrounding rock in mining roadways.The existing research mostly divides the advanced support area under static load conditions.Further exploration is needed for the division of advanced support area under dynamic load impact and the relationship between roadway surrounding rock and hydraulic support.Taking the 5304 working face roadway of Zhaolou Coal Mine as the research object,the variation features of working resistance of hydraulic support under dynamic load impact and the relationship between surrounding rock and hydraulic support are analyzed.The concept of dynamic coefficient is proposed.Under the action of dynamic load disturbance,the peak point of advanced support pressure will transfer to the interior of the coal body,resulting in a new plastic zone.Therefore,the area affected by advanced support pressure is divided into fracture zone,plastic zone,elastic zone,original rock stress zone,and newly added plastic zone.According to the coal rock state and dynamic boundary points,the advanced support area is divided into reinforced support section,auxiliary support section,and original support section based on dynamic stress as the boundary.The reinforced support section is composed of fracture zone,plastic zone,and partially elastic zone,and requires high-strength advanced support equipment to strengthen roof support.The auxiliary support section is mainly composed of elastic zones and requires single hydraulic pillars or unit hydraulic supports for auxiliary support.The original support section is located in the original rock stress zone as a whole,and there is no need to strengthen the support.The numerical simulation is used to study the variation law of advanced support pressure under dynamic load,and establish a calculation model for advanced support pressure in roadways under dynamic load.The dynamic stress expression for each support section is derived.The on-site test results show that the support scheme designed based on the division of the advanced support area of the roadway has good support effect and can meet the quality requirements of the advanced support area.