破碎矿岩预应力全长锚固数值分析

Numerical Analysis of Full-Length Anchored Bolt with Pre-Stressed In Broken Rock Mass

中色集团卢安夏铜业公司巴鲁巴铜矿下盘凿岩巷道矿岩破碎,易风化垮塌,遇水易泥化崩解。普通注浆锚杆无法满足此处巷道稳固性要求,考虑使用预应力锚杆,给围岩提供主动支护。利用FLAC3D软件对开挖和支护过程进行模拟。分析并比较了全长锚固的预应力注浆锚杆和普通注浆锚杆在控制巷道变形中的不同力学原理。模拟显示,预应力注浆锚杆能够减少巷道顶板沉降量达10 mm以上,相比普通注浆锚杆,提高了近2倍。因此,在矿岩破碎带,采用预应力注浆锚杆维护巷道稳定性是有效的也是必要的。为了达到更好的支护效果,还需对巷道顶板和边墙喷射混凝土,形成喷锚联合支护。

The rock mass in the drilling tunnel foot wall in Baluba copper Mine（CNMC Luanshya Copper Mines Pls.） is broken,its feature of weathering making the rock easily collapsed,and it is susceptible to argillitizated and disintegrated contacted with water.The traditional grouting bolt can not satisfy the requirement of tunnel stability,so the pre-stressed bolt-provide active support was adopted.The excavation and support process was stimulated by FLAC3D,and analyzing and comparing the different mechanical principles between full-length pre-stressed anchored grouting bolt and general grouting bolt in controlling the tunnel deformation.The numerical result shows that pre-stressed bolt can reduce subsidence of the roof more than 10 mm,which is about 2 times as long as general grouting bolts.Therefore,it is necessary and effective to use the pre-stressed grouting bolt in area of broken rock.Finally,to achieve better supportive effect,shotcrete must be injected to roof and side walls,which is called the combined support.