岩体力学参数变异性及取值方法

受结构和赋存环境的制约,岩体力学性质及其力学参数具有显著的时间和空间变异性.岩体力学参数和岩体质量从不同的侧面反映了岩体力学性质,两者具有必然的关联性,故可用相对简单的岩体质量评价来选取岩体力学参数:按地质条件将岩体空间离散为若干连续微元体单元;采用Q、RMR和BQ等方法逐一对各单元开展岩体质量评价,并利用岩体质量与岩体力学参数间的关系(如Hoek-Brown经验准则)计算其力学参数;综合各单元的计算结果确定反映连续岩体空间内空间变异特征的力学参数.以某水电站地下洞室群为例,实现了工程区围岩力学参数的不连续取值.

Variability of Mechanical Parameters of Rock Mass and Its Selection Method

A reasonable selection of mechanical parameters of rock mass for a project is very hard, because the mechanical properties and the parameters have the remarkable characteristics of spatial and temporal variability due to rock mass structure and existing environments. Both the mechanical parameters and the rock mass quality reflect the mechanical properties from different aspects and are interrelated each other, but the latter can be determined more easily than the former, so it is feasible to select the mechanical parameters of rock masses through the estimated results of rock mass quality. Based on analysis of geological conditions of rock mass, rock masses space of a project can be divided into lots of continuous cells, whose rock mass quality can be eas- ily given by such system as Q, RMR and BQ. The mechanical parameters of each cell can be calculated through the relationship between rock mass quality and mechanical parameters, for example the Hoek--Brown criterion. All the mechanical parameters of whole rock masses in a project space which reflects the spatial variability can be gotten by integrating the results of all cells. Take the underground works of a hydropower station as example, the mechanical parameters of surrounding rocks are gained using the methods mentioned as above.