河流作用诱发黄土滑坡机理

Mechanism of loess landslide induced by river action

在对泾阳南塬实地调查中发现,位于泾河与塬边交切处,发育有数量较多的黄土滑坡,分析认为河流作用是该类滑坡发生的主要诱发因素。通过实地调查,对饱和Q2黄土进行减围压三轴剪切试验以及数值模拟,研究河流作用诱发黄土滑坡的形成机理。研究表明:土体抗剪强度与应力路径有关,减围压三轴剪切状态下,土体抗剪强度指标小于常规三轴剪切状态下的抗剪强度指标,土体更容易发生剪切破坏;斜坡坡脚处存在关键块体,对斜坡整体稳定性起着控制作用。河流作用诱发黄土滑坡就是因为河流的持续侧蚀,造成坡脚关键块体逐步滑塌,最终导致斜坡失稳滑动。

Through the field investigation,it is found that there are some loess landslides located at the intersection of the southern tableland of Jingyang and Jinghe river.It is considered that the river action is the main triggering factor.The paper used field investigation,confining pressure-reducing triaxial compression shear test(RTC)on saturated Q2 loess and numerical simulation to study the formation mechanism of landslides induced by river action.It is concluded that the shear strength of the soil is related to the stress path.The shear strength under triaxial compression shear of reduced confining pressure is smaller than that under the conventional triaxial shear.The soil is more susceptible to shear failure under the triaxial compression shear of reduced confining pressure.There are key blocks at the foot of the slope,controlling the overall stability of the slope.The role of river in inducing loess landslides is due to the continued lateral erosion of the river,resulting in the gradual collapse of the key blocks,ultimately leading to a slippage of the slope.