节理化软岩开挖边坡变形及稳定性分析

Deformation and stability analysis of jointed soft rock excavation slope

南京秦淮东河铜家山段河道开挖后形成高度接近50 m的高边坡,边坡岩体主要为黄马青组(T_(2h))泥质粉砂岩,根据其饱和单轴抗压强度确定在地层岩石为软岩,岩体内发育多组包括层面在内的节理。边坡开挖后其稳定性受该组地层影响较大,本文采用有限元法对该边坡的变形和稳定性进行分析,计算时将岩体分别看作均质各向同性介质和节理化岩体两种情况来考虑。当将岩体看作均质各向同性材料时,开挖后边坡的变形较小,边坡稳定性系数满足安全性要求。当将岩体看作节理化岩体时,节理化有限元计算结果表明边坡变形较大,稳定性不满足安全性要求。分析结果表明,该软岩边坡的变形和稳定性受节理影响较大,考虑开挖后的加固设计时需要充分考虑岩体中节理对边坡的稳定性影响。

The Tongjiashan section of Qinhuai east river would be excavated, and the height of the new slope will arrive 70m, the main stratum of in the slope is Huangmaqing group （ T2h ） , including argillaceous siltstone, which saturate uniaxial compression strength is not more than 10MPa and can be looked as the soft rock. In the rock mass, several joints were found. The stability of the excavated slope will be affected by the soft rock. In this paper, the deformation and stability of the slope are analyzed by the finite element method, during calculation, the two cases are considered： （ 1 ） the rock mass is homogeneous isotropic; （ 2 ） the rock mass is jointed rock mass. When the rock is homogeneous isotropie, the deformation of the excavated slope is very small, and the slope is stable and safe; when the rock mass is jointed, the deformation of the slope is great, and the slope is not safe. The results indicate that the deformation and stability of the soft rock slope would be affected by the joints, the affection of the joints rock mass should be considered adequately in the reinforcing design.