G318国道宗噶求下村～大竹卡段地质灾害特征与典型点稳定性分析

Characteristics of Geological Hazards and Stability Analysis of Typical Slope along G318 Road from Zongaqiuxia Village to Dazhuka Village

西藏地区地质构造复杂且活跃,地形地貌差异大,是我国地质灾害最发育的地区之一。随着南亚交通廊道的建设上升为国家战略,区域已有或拟建交通线路沿线的地质灾害成为制约地区建设发展的瓶颈。文章在国家南亚交通廊道建设的大背景下,基于对西藏境内主要交通线路沿线地质灾害调查分析的基础上,选取G318国道仁布境内雅鲁藏布江峡谷区域宗噶求下村~大竹卡段沿线的典型地质灾害进行调查分析,主要针对路段内频繁发育的砂土、砂石土路基塌陷和边坡滑塌进行成因探讨。分析认为,该类地质灾害的形成与区域的地质构造、岩性、地形地貌、气候密切相关。地质构造、岩性、气候条件决定了砂土颗粒的形成,地形地貌条件决定了边坡的形态、分布特征。同时采用极限平衡法对切达村滑坡物质的剪切强度参数进行反演计算,并将结果运用到整个滑坡体稳定性分析中,采用Geostudio软件进行稳定性模拟计算分析,初步判断未来的发展趋势和破坏模式。

There are complicated and active geological structures in Tibet,with complex terrain landform.Tibet is one of areas with the most developed geological hazards in China.With the construction of south Asia transport corridor upgrading to national strategy,geological hazards along traffic lines in Tibet have become the bottleneck which restrics the development of regional construction.Under the background of Asia transport corridor construction for national strategy and based on the geological hazards investigation and analysis on the major transport routes in Tibet including G318,G219and G317,in this paper G318road from Dazhuka village to Zongaqiuxia village in Renbu county is selected,and the mechanism and features of sandy soil,and gravel soil slopes subsidence and subgrade subsidence are discussed.The analysis shows that the frequent geological hazards are closely related to the regional geological structure,lithology,terrain landform and climate.These factors determine the formation of sand,and the terrain landform determine the shape and distribution of slope.Meanwhile,in this paper limit equilibrium method is adopted to back analysis the shear strength parameters of landslide material and the results are used to analyze the stability of whole landslide.Geostudio software is used to simulate the stability of slope and subgrade of G318road and to judge the trend of development in the future.