云南昭通窝子箐滑坡稳定性分析

Stability Analysis of Woziqing Landslide in Zhaotong,Yunnan

云南昭通是我国地质灾害频发区域,特别是在降雨和地震条件下往往导致严重的危害。位于昭通市昭阳区的窝子箐滑坡威胁坡底数十居民的生命财产安全,因此对该坡体进行地质结构调查和稳定性研究十分必要。基于现场地质钻探和槽探确定窝子箐滑坡的表层为松散的残坡积土和耕植土,下部为全风化和强风化的玄武岩,且玄武岩明显得受到了地质构造界面切割。地质调查同时表明该坡体在破碎的全-强风化玄武岩中存在两个潜在的滑移面。在雨季和2014年鲁甸"8·03"地震中,窝子箐坡体局部发生了少量变形。利用Geo-Slope软件进行了天然状态、降雨状态、地震状态、降雨和地震共同作用4种工况下窝子箐滑坡的稳定性分析,结果表明天然状态下坡体稳定性较好,滑动面Ⅰ稳定性系数为1.41,滑动面Ⅱ稳定性系数为1.31。降雨和地震共同作用下稳定性系数达到最低,滑动面Ⅰ稳定性系数为1.01,滑动面Ⅱ稳定性系数为0.93。降雨和地震条件下窝子箐滑坡稳定性系数出现显著降低,存在滑动失稳的可能。

Zhaotong of Yunnan province is an area frequently suffered from geological disasters in China. Especially in earthquakes and rainfalls,it often leads to serious damage. Woziqing landslide, located in the Zhaoyang District of Zhaotong City, Yunnan Province, China, is threating dozens of people＇s life and property. Therefore, it is necessary to investigate the geological structure and analyze slope stahitity. Based on the field geological drilling and trenc- hing, the surface of the landslide was composed of residual soil and planting soil, the lower part were completely weathered and strongly weathered basalt. And the basalt was obviously cut by the geologic.al tectonic interface. Ge- ological survey also showed that two potential slip surfaces were in the broken full weathered basalt. In the rainy season and during the Ludian 8.03 earthquake, the Woziqing landslide appeared small deformation. The Geo - Slope software was used to analyze the stability of Woziqing landslide under natural, rainfall, earthquake and the in- teraction of rainfall and earthquake conditions. The results showed that the stability of Woziqing landslide was good under natural condition. The stability coefficient of the Woziqing landslide was 1.41 at the position of potential slid- ing surface I , and 1.31 at the position of potential sliding surface Ⅱ. The stability coefficient of Woziqing land- slide was lowest under the interaction of rainfall and earthquake. It was concluded that stability coefficient at the position of potential sliding surface I was 1.01, at the position of potential sliding surface Ⅱ was 0.93. Under earthquake and rainfall conditions, the stability of Woziqing landslide reduced obviously and instability may appear.