浅层破碎岩体巷道全长锚固稳定性控制

Stability Control of Full-length Anchorage upon Roadways in Shallow Broken Rock Mass

借助于修正的RMR法对首云铁矿巷道围岩进行岩体工程质量评价分级,采用理论计算与ANSYS软件模拟对巷道开挖后塑性区的形成过程和二次应力分布加以研究,得出浅层破碎围岩无支护时塑性区特性及全长锚固条件下应力分布规律;同时,依据锚杆轴力测试结果,指出在兼有软岩及硬岩双重特性的浅层破碎岩体中宜根据岩体工程质量采用长短结合的成组锚杆支护方式,并辅助喷射适当厚度混凝土层封闭围岩以实现巷道稳定性控制,首云铁矿Ⅲ矿带破碎围岩巷道支护改进的实践验证了其支护效果的优势。

By the modified RMR method,the engineering quality of surrounding rock mass in roadway was classified for Shouyun Iron Mine. And the study on the forming process of plastic zone and secondary stress distribution of roadway after excavating was conducted through theoretical calculation and ANSYS simulating. The unsupported features of plastic zone and the stress distribution law under the condition of full-length anchorage were achieved for the shallow broken rock mass. Meanwhile,the axial force along the rock bolt was tested,which proved that group rock bolts comprised of long and short bolts should be adopted to support the surrounding rock in shallow broken rock mass which had a double characteristic of soft rock and hard rock. In addition,an appropriate thickness of shotcrete layer was a supplement for stability control. Finally,the results above were applied to improve the supporting for broken surrounding rock mass in III ore zone,which verified the advantages of the supporting effect.