顶板软弱夹层渗水泥化对巷道稳定性的影响

Argillation of a Roof Weak Interlayer due to Water Seepage and Its Influence on Roadway Stability

在现场原位探测与实验室组分实验基础上,分析测试了典型巷道顶板软弱夹层的赋存特征和岩性组成,得到了软弱夹层岩体黏土成分遇水泥化特性和不同支护方式下注浆固结体内聚力C与内摩擦角φ的演化规律.结合数值计算与相似材料模拟等手段研究了软弱夹层不同层位、泥化特性和动压影响导致软弱夹层顶板巷道失稳垮冒的规律.结果表明:软弱夹层位于锚杆锚固区边缘时顶板安全状况最差,渗水泥化后围岩结构承载力学性能急剧降低,动压作用后软弱夹层岩体发生剪切破坏使得顶板失稳垮冒.提出了针对软弱夹层渗水泥化巷道的安全控制对策,并成功应用于现场工业性实践.

Weak roof inter-layers were studied by field location, sample collection and laboratory examination. The occurrence and litho-logic composition of the inter-layers were analyzed. A law relating cohesion and friction angle of grout concretion under various supports to the argillation status of the clay-water composition was developed. The relationship of roof collapse to the condition of the weak inter-layer, its location and the effects of seepage was modeled by numerical simulation and by construction of ＂similar material＂ models. The results show that a weak inter-layer located at the edge of the anchorage zone is seen to be the worst case for roof safety. Likewise, seepage rapidly reduces the mechanical properties of the surrounding load bearing structure. And dynamic-pressure induced a weak inter-layer, which resulted in shear failure. Countermeasures for keeping roadways with seeping weak inter-layers safe are proposed and put into practical application.