Risk analysis of two-layer clay slopes considering spatial variability of shear strength
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摘要: 土性参数空间变异性具有各向异性的特点,因而采用各向异性随机场来描述边坡参数空间分布的特征更为合理。针对某一双层黏土边坡,基于土体抗剪强度的各向异性随机场,研究了土体参数的竖向波动距离、水平向波动距离和变异系数对边坡失稳概率、失稳模式和风险评估的影响。主要得到的结论如下：随着COV的增大,边坡失稳风险逐步增大,在低变异性土体中,几乎没有边坡失稳风险。整体而言,边坡失稳概率和边坡失稳风险随变异系数的变化规律保持一致性。深层滑动模式占比很大,但随着COV的增大,深层滑动模式逐步向浅层滑动模式过渡；当波动距离（包括水平向和竖向）增大时,边坡失稳概率和失稳风险均相应增大,但当波动距离超过一定大小（表现与边坡尺寸相关）时,失稳概率和失稳风险受到波动距离增大的影响幅度变小。Abstract: Anisotropy exists in the spatial variability of soil parameters. Therefore, it is rational to indicate the spatial distribution of slope parameters using anisotropy random fields. Based on the anisotropic random field of shear strength of soil for a two-layer slope, the effects of vertical scales of fluctuation, horizontal scales of fluctuation and coefficient of variation (COV) of soil parameters on the slope failure probability, instability modes and risk assessments are studied. The main conclusions are drawn as follows: with the increase of COV, the risk of slope failure gradually increases. In low-variability soils, there is almost no risks of slope failure. On the whole, the failure probability of slope is consistent with the risk of failure as COV increases. The deep-layer slop mode accounts for a large proportion, but with the increase of COV, the deep-layer slope mode gradually becomes the shallow slope one. When the scale of fluctuation (including horizontal and vertical) increases, the failure probability of slope and risks increase accordingly. However, when the scale of fluctuation exceed a particular size, which is related to the size of the slope, the increasing amplitude of failure probability and risks slows down as the scale of fluctuation increases.
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Keywords:
- anisotropy /
- random field /
- two-layer clay slope /
- probability of failure /
- risk of failure
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图 3 边坡安全系数均值与随机计算次数的关系
Figure 3. Relationship between mean value of safety factor of slope and number of stochastic calculations
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