巷道复合顶板变形破坏特征与冒顶隐患分级

Deformation and failure characteristics and roof caving hidden danger classification of roadways compound roof

煤层顶板岩性复合及分层厚度变化大,稳定性差异显著。针对巷道层状复合顶板条件,采用现场探测、数值模拟、理论分析等方法,研究了顶板岩层结构分类、顶板变形破坏特征与平衡结构及冒顶隐患评价。研究表明:巷道复合顶板岩层结构可分为坚硬岩层、软弱岩层、下软上硬、下硬上软、软硬渐进、硬软相间及软硬相间等7个类型。对于较差的顶板岩层结构,在层面和节理影响下,巷道顶板下位分层形成离层、随动稳定状态的铰接岩块结构及亚稳定状态的裂隙弯曲结构,其范围和承载能力与顶板岩层结构类型有关,顶板变形和锚索延伸量呈现不协调性。采用锚索是否破断失效作为分级指标,建立了冒顶隐患的分级方案,划分了典型顶板岩层结构的隐患等级,对3个级别的冒顶隐患进行了安全评估。

With compound lithological and great variation of stratification thickness, stability of coal mine roof differs significantly. Aiming at layered compound roof, using field detection, numerical simulation, theoretical analysis, strata structure classification, deformation and characteristics, balanced structure and caving hidden danger of roof were stud- ied. The study results show that the strata structure of roadway compound roof can be classified into seven types ： hard strata, soft strata, lower-soft upper-hard, lower-hard upper-soft, soft-hard progress, soft-hard alternation and hard-soft al- ternation. Under the effect of stratification and joint, the lower layers of poor strata roof form separation, stochastic sta- ble hinged rock structure and metastable fracture bending structure, and its scope and bearing capacity is related to roof structure classification, roof deformation and cable extension presents incoordination. Taking cable status as classif- ying index, the classification scheme of roof caving hidden danger was established, classified hidden grade of typical roof strata structure, safety assessment was carried out.