穿435m落差断层大巷的地质保障及施工控制技术

GEOLOGICAL GUARANTEE AND CONSTRUCTION CONTROLLING TECHNIQUE OF MAIN ROADWAY CROSSING FAULT ZONE WITH 435-m FALL

以穿过435m落差、140m宽度断层带的主运输大巷的安全开掘为工程背景,研究特大断层区巷道施工地质保障及围岩控制技术。在断层岩性组成、断层岩芯剪切滑动面擦痕特征、断层导水特性及现代活动性等研究的基础上,结合区域地质分析判定穿该断层区域巷道施工不会遭受到断层突水威胁,施工的关键在于巷道顶板安全控制,针对性地提出化学浆液预注浆控制迎头空顶区岩体垮冒技术。如何防止超大范围断层破碎带内松散泥质岩体渗水泥化则是成巷后的最大技术问题;高强预应力锚杆支护和滞后强化注浆技术相结合可有效防止泥化,实现巷道长期维护。针对顶板状况设计两种技术方案,采取分步实施的动态施工工艺,在围岩顶板空顶自稳时间很短时,采取超前预注浆和喷层、架棚、注浆、锚杆组合技术方案;在围岩空顶自稳期间允许施工锚杆时,采用锚杆、注浆和关键部位锚索加固方案,保证了巷道的施工安全和长期稳定。

Taking safe construction of the main haulage roadway drilling crossing a 435-m fall and 140-m wide fault zone as engineering background,a study of engineering geological guarantee and construction controlling technique of roadway are performed. Based on the fault rocks,scraping characteristics of rock core shear-sliding surface,water conductivity,recent activities of the faults and regional geological analysis,it is found that roadway construction will not be subjected to fracture water outburst. The key construction technique lies in successful control of head-on hollow roof rock collapse. Under this point,grouting of chemical serum should be chosen as a precaution. Once the roadway is formed,it is important to control large-scale water seepage caused by argillitization of broken loose mudstone and keep long-term stability of roadway. So combination of lag-grouting of controlling rock mass weakened by fracture water and high-intensity pretension supporting to prevent continuous rheological deformation is advocated. As a result,two supporting schemes were considered:as long as self-stability of the roof rock is allowed,the stepwise bolting with anchorage cables installed at key area will be adopted;otherwise,the pre-grouting,spraying,shedding and bolting scheme will be selected instead. Process controlled project is highlighted by dynamic use of advancing pre-grouting,spraying,shedding and bolting to guarantee the roadway′s safe construction.