采用岩体分级方法(RMR法)、Q系统和地质强度(GSI)指标对矿岩进行了工程地质评价,并通过扩展后的Hoek--Brown节理强度准则进行岩体力学参数确定.根据白羊矿段矿柱布置形式,推导出矿柱荷载公式,并确定了矿柱强度计算参数.针对井下矿柱主要破坏形式分别进行失稳机理分析.将正交设计法引入采场结构参数优化分析中,对各开采方案进行了三维数值模拟.运用正交极差分析法对矿柱稳定性影响因素敏感度进行评价.实践结果表明:采场高度控制在3.5~4.5 m,矿房宽度取值不大于5 m,矿柱直径不小于3.5 m留存矿柱稳定性基本能得到保障.
After a proper engineering geological evaluation with rock mechanics rating(RMR) method,Q system and geological strength index(GSI),the mechanical parameters of rock masses were obtained by the extended Hoek-Brown failure criterion.According to the pillar layout of Baiyang ore section,a formula of pillar load was derived,and some parameters for calculating the pillar strength were also determined.The pillar instability mechanisms were respectively analyzed in view of main failure modes.Orthogonal design was introduced to optimization of the stope structure parameter.On this basis,the three-dimensional numerical simulation of each mining program was carried out.The sensitivity of influencing factors for pillar stability was assessed using the method of orthogonal range analysis.The practice shows that the stability of retention pillars can be safeguarded when the stope height is controlled in the range of 3.5 to 4.5 m,the stope width less than 5 m,and the pillar diameter not less than 3.5 m.