地下厂房围岩块体稳定分析及支护优化研究

Rock Block Stability and Support Optimization of Underground Powerhouse

目前支护优化分析大多数采用有限元进行计算,但有限元将围岩视为均匀介质,其计算结果很难符合以围岩等级为标准的支护设计要求。本文基于块体理论的支护优化分析,充分考虑了围岩中断层、岩脉和节理相对位置,通过块体分析软件(Unwedge)综合评价定位、半定位和随机块体的几何特征、滑动机理和稳定性状。进一步比较了不同支护方案的支护效率和不同块体类型在不同支护方案下平均安全系数的增长率,优选出各种块体类型相对应的支护方案。在此基础上合理调整支护方案空间分布,达到支护优化设计的目的。对某水电站地下主副厂房支护优化分析表明:加密锚杆的布置,可以有效的增加主厂房拱顶块体的安全系数;增加锚杆长度对提围岩安全系数不太明显。

At present, most of support optimizations are analyzed by FEMI but their results hardly conform to the support design requirements on the surrounding rock classification because of that the FEM takes the surrounding rock as homogeneous materials. The block-theory-based software ＇ Unwedge＇ is used to evaluate the geometric features, sliding mechanism and stability of random block, positioned block and half-positioned block by considering the relative position of fault, dike and joint in surrounding rock. Furthermore, the support efficiency at various cases and average safety factors of different blocks are compared to obtain the optimal solution. The support optimization for some underground cavities shows that making the anchor bolts denser can increase effectively the safely factor of top block of the main cavity, but making the anchor bolts longer plays a little role to boost the safety factor of surrounding rock.