岩土参数空间变异性对滑坡滑动深度的影响

Impact of spatial variability of geotechnical parameter on slipping depth of landslide

在边坡相关的研究中考虑岩土参数的随机性和不确定性,可充分了解岩土参数空间变异性带来的影响。为此,通过随机有限元方法建立二维土性参数随机场,基于Monte Carlo方法构建随机有限元计算程序,进行了8400组数值模拟实验,运用概率分析方法,通过对比确定性情况下得到的均质边坡滑动面的深度来研究岩土体参数空间变异性对边坡滑动深度的影响。结果表明:(1)考虑各向异性非均质的土坡分析比均质土坡分析得到的滑动深度更符合实际结果;(2)在考虑岩土参数空间变异性时,无论其各向异性如何变化,滑坡最大概率发生滑动的深度范围总是一致的;(3)不同的各向异性值实际体现为土体的分层,土体分层将影响滑坡的滑动深度,其他条件不变的情况下,边坡的各向异性值越大(土体分层越明显),深层破坏的概率越小。研究成果有利于引导进一步研究更接近“自然”状态的边坡,对于工程项目的预警和防治有参考价值。

The impact from the spatial variability of geotechnical parameter can be fully understood under the consideration of both the randomness and the uncertainty of geotechnical parameters in the studies related to slope.Therefore,a two-dimensional random field of soil parameter is established through random finite element method,while a random finite element calculation program is built up on the basis of Monte Carlo method,and then 8400 sets of numerical simulation experiments are carried out;from which the impacts from the spatial variabilities of the geotechnical parameters on the slipping depth of landslide are studied through comparing the depths of the homogeneous slope slipping planes obtained under the deterministic conditions.The study results show that(1)the slipping depth obtained from the analysis made on the earth slope under the consideration of heterogeneity anisotropy is more coincided with the actual result than that obtained from the analysis made on the homogeneous earth slope;(2)When the spatial variabilities of geotechnical parameters are considered,the slipping depth ranges for the maximum probability of the occurrence of landslide are always consistent,no matter how the anisotropy of heterogeneity changes;(3)The different values of anisotropy are actually reflected as the layering of soil mass and the slipping depth of landslide is to be impacted by the layering of soil mass.When the other conditions remain unchanged,the larger the value of anisotropy(the more obvious the layering of soil mass)is,the lower the probability of a deep failure is to be.The study result is favorable to guide the further study on the slope that is closer to natural status,and then has a referential value for the early warning and prevention of landslide for the relevant engineering projects.