金沙江中游沿江高速公路地质灾害差异性分布特征与成因机制

Differential Distribution Characteristics and Genetic Mechanism of Geological Hazards, Expressway along the Middle Reaches of Jinsha River

金沙江位于青藏高原东南缘,跨越中国第一、二地貌阶梯过渡带,流域内地质灾害频发。四川沿江高速是“一带一路”“长江经济带”的重要支撑项目,对凉山州发展具有重大战略意义。为了研究金沙江中游沿江高速屏山—金阳段地质灾害的差异性分布这一特殊现象,通过遥感解译、实地调查和数据分析等方法,对研究区地质灾害发育的背景条件与特征进行了系统梳理,分析了地质灾害差异性分布的成因机制,提出了研究区不同灾害类型的防治对策并验证了防治效果。研究表明:沿江高速屏山—金阳段地质灾害表现为年降雨量大的屏山县泥石流灾害发育的比例远远低于年降雨量小的雷波县和金阳县;地形地貌、地质构造与地震活动是差异性分布的内部因素;临界降雨量和人类工程活动则是差异性分布的外部因素。可见内外因素共同主导着研究区内地质灾害的差异性分布。

The Jinsha River is located on the southeastern edge of the Qinghai-Tibet Plateau,spanning the transitional zone between the first and second geomorphic terraces in China.The basin is prone to frequent geological hazards.The Sichuan section of the Along-Jinsha Expressway is an important supporting project for“The Belt and Road Initiative”and the“Yangtze River Economic Belt”,which is of great strategic significance to the development of Liangshan Yi Autonomous Prefecture.In order to investigate the unique phenomenon of the differential distribution of geological disasters along the Pingshan-Jinyang section of the Jinsha River,the background conditions and characteristics of geological hazard development in the study area were systematically combed through remote sensing interpretation,field investigation and data analysis.The genetic mechanism of the differential distribution of geological hazards was analyzed,and corresponding prevention and control strategies for different hazard types was proposed in the study area.The findings are as follows:the geological hazards along the Pingshan-Jinyang section of the expressway mainly consist of debris flows in Pingshan County,where the proportion of their development is significantly lower compared to the lower annual rainfall areas of Leibo County and Jinyang County.Topography,geomorphology,geological structure and seismic activity are the internal influencing factors for the differential distribution.Critical rainfall and human engineering activities are the external factors contributing to the differential distribution.Both internal and external factors jointly dominate the differential distribution of geological hazards in the study area.Targeted prevention and control strategies are proposed based on different types of geological hazards.