转化型二次失稳边坡变形特征及失稳成因分析 ——以余凯高速RK24滑坡为例

RK24滑坡由浅层滑动逐渐转化为深层滑动,是一个转化型二次失稳边坡典型案例.在RK24滑坡详细调查基础上,研究转化型二次失稳边坡的变形特征与失稳成因,并提出相应的治理措施。结果表明:①合理划分滑体横纵剖面,有限的监测数据能准确反映滑体内部变形情况,变形量差值拐点为滑面,稳定区域局部异常点裂隙发育;②丰富松散物源、优势节理构造提供基础条件,降雨或地震诱发边坡失稳,施工和运营过程中的震动效应促使工程滑坡浅层向深层转化;③工程治理需综合考虑二次滑面深度、失稳原因和既有工程的破坏情况等,由于强降雨导致的二次失稳,需加强排水引流,由于震动效应导致的二次失稳,需二次支挡加固。

Analysis of Deformation Characteristics and Instability Cause of the Transformed Secondary Landslide - A Case of the RK24 Landslide at Yuqing - Kaili Expressway

The RK24 landslide is a typical case of transformed secondary landslide of shallow landslide transforming into a deep one, which is a secondary slide based on the existing engineering structure. Based on the detailed investigation of RK24 landslide, we analyzed its deformation characteristics, instability cause and control measures. The research results show that the limited monitoring data can accurately reflect the internal deformation of the sliding body with reasonable division of transverse and longitudinal of the sliding body, there are slide surfaces in the inflection points of deformation difference value, and there are cracks in the local abnormal points in the stable region. Abundant loose material source and dominant joint structure provide fundamental conditions. Rainfall or earthquake can trigger the transformed secondary landslide, and the shaking and disturbance in the process of construction and transportation force the transformation from shallow to deep. Control measures should consider comprehensively, including the depth of secondary slip surface, the reason of instability and the failure of existing engineering and so on. The measures of instability triggered by heavy rainfall should be enhanced drainage, and the measures of instability caused by shaking should be supported and reinforced further.