硬岩CWFS模型的改进及其在岩质高边坡稳定性分析中的应用

连续介质模型(如Mohr-Coulomb等基于黏结强度组份和摩擦强度组份同时被调动的传统破坏准则)目前还不能有效预测隧道围岩脆性破坏的广度和深度。基于Mohr-Coulomb准则的黏结强度弱化–摩擦强度强化(CWFS)模型在这方面表现出良好的工程应用前景,但其在脆性硬岩高陡边坡稳定性分析中的应用研究还不多见。对硬岩的CWFS模型及其改进模型进行讨论分析,针对脆性硬岩在低围压条件下的特殊力学行为,将CWFS模型改进为黏结强度衰减–摩擦强度激活(CLFM)模型并应用到首钢水厂铁矿硬岩高陡边坡稳定性分析中。与Mohr-Coulomb准则计算结果的对比分析表明,扩帮后的边坡仍然处于稳定状态。Mohr-Coulomb准则低估了边坡的位移和坡脚的塑性区范围,高估了边坡的应力水平,与CLFM模型分析结果相比显得保守。另外,实测地应力场下的边坡位移计算结果是仅以自重应力形成的应力场下的位移计算结果的10倍左右。

IMPROVED CWFS MODEL FOR HARD ROCKS AND ITS APPLICATION TO STABILITY ANALYSIS OF HIGH ROCK SLOPE

Continuum models with traditional failure criteria(e.g.Mohr-Coulomb criterion) based on simultaneous mobilization of cohesion and frictional strength components cannot successfully predict the extent and depth of brittle failure of surrounding rocks in tunnels,while the cohesion weakening-friction strengthening(CWFS) model,rarely used in stability analysis of high rock slopes,has a good application prospect in engineering.Firstly,the CWFS model and its improved editions were discussed.Then the CWFS model was modified to be the cohesive losing and frictional mobilizing(CLFM) model according to the particular mechanical behaviors of hard rocks in low confinement conditions.Finally,the CLFM model was applied to the stability analysis of a hard rock slope,and the results were compared to those obtained by the Mohr-Coulomb criterion.It is demonstrated that the slope is still in a stable condition.Both the displacement and plastic zone at the foot of the slope are underestimated while the stress level is overestimated by the Mohr-Coulomb criterion.Furthermore,the displacement of slope under actual in-situ stresses is 10 times that under gravity stress field only.