江西省域范围持续性强降雨诱发层状土质边坡滑坡灾变机理研究

Study on Landslide Disaster Mechanism of Layered Soil Slope Induced by Continuous Heavy Rainfall in Jiangxi Province

依托江西省信江八字嘴航电枢纽建设项目,以江西省层状土质边坡为研究对象,利用自行研发的滑坡模拟设备和可调式降雨装置,研究滑坡产生机理,并与Geostudio2018软件模拟相互印证。结果表明,持续性强降雨条件下,内部成层结构会影响土体稳定性,不同倾向的层状土质边坡安全系数变化规律有较大差异;顺倾边坡坡体和坡面受强降雨破坏更严重,更容易发生滑坡;坡顶及坡脚应为滑坡防治的重点部位;倾向、成层结构会影响雨水入渗;层状土质边坡降雨入渗过程十分复杂,导致滑坡灾变具有一定的滞后性;在物理模型试验中,砂土、粉土的十字板剪切强度与含水率之间在一定含水率区间内呈线性关系,超过区间范围则线性关系不复存在。

Based on the construction of Bazizui Navigation and Hydropower Project in Xinjiang River,Jiangxi Province,the layered soil slope in Jiangxi Province is taken as the research object.The self-developed landslide simulation equipment and adjustable rainfall device are used to study the mechanism of landslides,and the model test results are verified with the simulation of Geostudio2018 software.The results show that,(a)the internal layered structure will affect the stability of the soil under the condition of continuous heavy rainfall,and the variation law of the safety factor of the layered soil slope with different tendencies is quite different;(b)the slope body and surface along the inclined side are damaged more seriously by the heavy rainfall and are more prone to landslides;(c)the top and foot of slope should be the key parts of landslide prevention;and(d)the tendency and layered structure will affect rainwater infiltration,and the process of rainfall infiltration in layered soil slope is very complex,which leads to a certain hysteresis of landslide disaster.In the physical model test,there is a linear relationship between the shear strength of cross plate and the moisture content of sand and silt in a certain range of moisture content,but the linear relationship will not exist if the moisture content is beyond the range.