围岩松动圈理论在某矿巷道支护优化中的应用

Application of the Loose Circle Theory of Surrounding Rock in the Optimization of Roadway Support in One Iron Mine

云南某铁矿山深部巷道变形严重,巷道经多次反复支护后未达到理想支护效果,给矿山安全生产带来隐患。为优化巷道支护效果,确定合理的支护参数,基于围岩松动圈理论计算分析巷道支护现状,选取对支护影响较大的3个因素设计正交试验,运用FLAC3D软件进行数值模拟。结果表明:巷道变形破坏的原因为形成的围岩松动圈等级同支护参数间的不匹配所致;在锚杆长度、锚杆间排距、喷层厚度3个因素中,喷层厚度对支护效果影响最大;在一定科学取值范围内,混凝土喷层厚度越大、锚杆长度越小、锚杆间排距越大,巷道顶板、两帮位移量越小,支护效果越好;最后,提出选用长1.8 m的锚杆、锚杆间排距1.0 m×1.0 m、喷射混凝土厚度100 mm的最优参数对巷道进行锚网喷支护。

The deep roadway deformation of an iron mine in Yunnan Province is serious,and the roadway fails to achieve the ideal support effect after repeated support,which brings hidden dangers to mine safety production.In order to optimize the effect of roadway support and determine reasonable support parameters,the current situation of roadway support was calculated and analyzed based on the loose zone theory of surrounding rock.Orthogonal tests were designed to select three factors that had a greater impact on the support,and numerical simulation was carried out by FLAC3D software.The results show that the cause of roadway deformation and failure is the mismatch between the grade of surrounding rock loose ring and supporting parameters.Among the three factors,the length of bolt,the spacing between bolts and the thickness of shotcrete layer,the thickness of shotcrete layer has the greatest influence on the supporting effect.In a certain range of scientific values,the larger the thickness of the concrete shotcrete layer,the smaller the length of the bolt,the larger the row distance between the bolt,the smaller the displacement of the roadway roof and two sides,the better the support effect.Finally,the optimal parameters of 1.8 m long bolt,1.0 m×1.0 m distance between bolt rows and 100 mm thickness of shotcrete are proposed to support roadway with anchor net shotcrete.