摘要
降雨入渗边坡稳定可靠度研究大多只考虑了土体饱和渗透系数空间变异性的影响,而忽略了土体抗剪强度参数空间变异性的影响。以无限长边坡模型为例,发展了可确定不同降雨历时边坡土体含水率分布和湿润锋深度的修正Green-Ampt入渗模型,探讨了土体多参数(饱和渗透系数和抗剪强度参数)空间变异性与降雨入渗相互作用下的边坡失稳机理,进而比较了不同降雨历时下的边坡失效概率。结果表明:考虑土体饱和渗透系数变异性时,降雨初期较小的饱和渗透系数变异系数对应较小的边坡失效概率,但随着降雨历时的增加,较小的饱和渗透系数变异系数反而对应更大的边坡失效概率。此外,降雨初期土体抗剪强度参数空间变异性引起的滑动面位置不确定性是影响边坡稳定性的关键因素。边坡除了会沿湿润锋附近和不透水层处失稳,还可能沿因抗剪强度参数空间变异性引起的软弱带处失稳,故考虑抗剪强度参数空间变异性对应的边坡失效概率更大。相比之下,降雨后期湿润锋的推进是影响边坡稳定性的关键因素,此时不管是否考虑了抗剪强度参数空间变异性边坡都主要沿湿润锋附近失稳,获得的边坡失效概率相近。
The current reliability studies on slope stability under rainfall infiltration only consider the spatial variability of saturated hydraulic conductivity of soils,while ignores that of shear strength parameters.An infinite slope model is taken as an example,and a modified Green-Ampt model is developed to determine the distribution of moisture content of soils and the wetting front depth within the slope under different rainfall durations.The failure mechanism of the infinite slope considering the interaction of the spatial variabilities of multiple soil parameters and the rainfall infiltration is investigated.Then the probabilities of slope failure under different rainfall durations are compared.The results indicate that a smaller coefficient of variation of saturated hydraulic conductivity induces a smaller probability of slope failure during the initial period of rainfall.However,it will result in a larger probability of slope failure as the rainfall sufficiently progresses.Additionally,during the initial period of rainfall,the uncertainty of slip surface location due to the spatial variability of shear strength parameters of soils will greatly affect the slope stability.In this case,the slope will fail along the weak zones induced by the spatial variability of shear strength parameters besides along the wetting fronts and impermeable layers.As a result,the probability of slope failure is larger when the spatial variability of shear strength parameters is considered.In contrast,the advance of the wetting front is the crucial factor that affects the slope stability during the late period of rainfall.In this case,the slope will fail mainly along the wetting fronts,and consequently the probabilities of slope failure will be similar no matter whether the spatial variability of shear strength parameters is taken into account.
作者
蒋水华
刘贤
黄发明
黄劲松
JIANG Shui-hua;LIU Xian;HUANG Fa-ming;HUANG Jin-song(School of Civil Engineering and Architecture,Nanchang University,Nanchang 330031,China;Key Laboratory of Tailings Reservoir Engineering Safety of Jiangxi Province,Nanchang 330031,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第5期900-907,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41867036,41972280,U1765207)
江西省自然科学基金项目(20192BBG70078,2018ACB21017,20181ACB20008)。
