开挖条件下大礼溪滑坡变形机理分析

Deformation Mechanism Analysis of Dalixi Landslide under Excavation Conditions

为分析开挖条件下大礼溪滑坡变形机理,根据现场调查,并结合滑坡变形特征,运用定性评价方法分析了滑坡的变形发展过程及其机理;发现软弱易风化的粉砂质泥岩坡体、不利的层状同向坡体结构及发育的节理构造是滑坡发生的内因;人工开挖与爆破引发的地震是引发滑坡的外因,降雨作用加速了滑坡变形。最后,通过数值模拟分析开挖条件下滑坡的应力场与位移场的变化,发现滑坡的应力调整与位移变化均具有渐进式变化的特点,分布在滑坡前缘、中部和后缘观察点最小总应力的平均值分别为18.347、-21.888、-76.450kPa;位移平均值分别为147.83、111.14、39.29mm。研究成果对防治滑坡灾害有重要意义。

In order to analyze the deformation mechanism of the Dalixi landslide under excavation conditions,according to the field investigation and combined with the landslide deformation characteristics,the qualitative development method was used to analyze the deformation development process and the mechanism of the landslide.The results show that the weak and easily weathered silty mudstone slope,the unfavorable layered isotropic slope structure and the developed joint structure are the intrinsic factors of landslide occurrence;The earthquake caused by the artificial excavation and blasting is the main external factor that leads to the landslide occurrence,and the rainfall action accelerates the deformation of the landslide.Finally,numerical simulation was used to analyze the changes of the stress field and the displacement field of the landslide during the excavation.The minimum total stresses distributed at the front,middle and trailing edge of the landslide were 18.347 kPa,-21.888 kPa and-76.450 kPa,respectively;the average displacements were 147.83 mm,111.14 mm and 39.29 mm.The research results are of great significance for the prevention and control of landslide disasters.