松软煤层复合顶板条件下大跨度切眼支护技术研究

为了研究松软煤层复合顶板条件下大跨度切眼支护技术难题，采用数值模拟、理论分析、现场监测方法，分析了切眼巷道变形、位移、破坏特征，确定了围岩类别和支护参数，提出了左旋螺纹钢锚杆+金属网+金属梁+锚索的联合支护技术。研究表明:无支护条件下切眼巷道围岩出现"蝶形"破坏，顶板和两帮是支护的关键部位，支护后切眼巷道顶板和两帮位移大幅度减小，顶板应力释放区垂直应力明显减小，两帮应力集中区垂直应力增加，巷道顶、底角剪应力集中区范围减小。现场监测结果显示支护满足安全生产要求，为类似地质条件巷道支护提供借鉴。 

Support technology of large span open-off cut under compound roof in mining soft coal seam

In order to study the support technology of large span open-off cut under the condition of compound roof in mining soft coal seam, numerical calculation, theoretical analysis, and site measurement were applied to research the deformation, displacement and failure characteristics of large span open-off cut. The surrounding rock type and support parameters were identified, and the combined support with left-hand rebar bolt, metal net, metal beam and anchor was designed. The results show that there was butterfly destruction under surrounding rock of open-off cut under no-support condition, and the roof and walls of open-off cut were critical zones of support. After supportting, the displacement of roof and walls of open-off cut reduced, the vertical stress in stress relief area of roof was obviously reduced, and the vertical stress in stress concentration area of walls increased. The range of the shear stress concentration zone formed at the vertex angle and the bottom angle of open-off cut is reduced. The results of on-site monitoring show that the support can meet the safety production and provide reference to roadway support under similar geological conditions.