高边坡倾倒式危岩体落石分析及防护设计

Analysis on Rockfall and Protective Design of Toppling Dangerous Rock Mass in High Slope

现有的路堑高边坡由于当时开挖作业,必然改变了坡体的应力状态以及应力路径;由于卸荷的作用,坡体内部的节理裂隙张开,在开挖边坡面附近的坡体一定范围内形成了松弛区。松弛区内部分危岩体脱离母岩,形成落石。针对广州地铁南沙平高边坡施工过程中引发的落石进行计算分析,对比考虑坡体植被阻尼作用条件下与未考虑坡体植被阻尼作用落石运动状态、停留位置、运动时间和速度特征以及与坡面碰撞等,并采用柔性支护方式拦截落石。结果表明:植被对落石阻尼作用明显;柔性防护措施有很好的工程效果。

The stress state and path have been changed due to excavation in high cutting slope; under the effect of unloading, the joints and fissures have opened which generates a relaxation area near the excavation surface. The partial dangerous rock mass in the relaxation area will break away from mother rock to form rockfall. Carry out calculation and analysis on the rockfall triggered during the construction of Nanshaping high slope in Guangzhou subway, compare the rockfall state of motion, stopping position, time of motion, velocity characteristics and collision with slope surface by considering and not considering damping effect of vegetation and use flexible support method to intercept the rockfall. The results show that damping effect of vegetation on the rockfall is distinct and the flexible preventive measures have a good engineering effect.