Importance of variability in initial soil moisture and rainfalls on slope stability
Importance of variability in initial soil moisture and rainfalls on slope stability
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初始土壤湿度和降雨量的变化对边坡稳定性的重要性
DOI：
10.1016/j.jhydrol.2019.01.046
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发表时间：
2019-04-01
影响因子：
6.4
通讯作者：
Wen, Jet-Chau
中科院分区：
文献类型：
--
作者：
Cai, Jing-Sen;Yeh, Tian-Chyi Jim;Wen, Jet-Chau
考虑初始土压力和土壤水力学性质的空间变异性以及降雨的时间变异性，采用一阶矩分析方法研究降雨过程中边坡稳定性不确定性的时空传播。分析结果表明，初始孔隙水压力分布和孔隙水压力分布的变异性所引起的不确定性与土壤水力学性质的变异性所引起的不确定性是相当的。此外，边坡稳定性不确定性的演化是由平均流场驱动的，并且沿着边坡剖面沿着形成局部大不确定性区域，导致局部低可靠性区域，这可能导致边坡的破坏。特别是，当边坡接近饱和时，即使在降雨初期，边坡任何高程的稳定性分析的可靠性也很低。另一方面，当边坡处于非饱和状态且发生严重滑坡时，低可靠度区存在于边坡的早期浅层。结果还表明，在降雨量呈下降趋势的早期，与均匀和增加趋势相比，在浅深度处存在更大的不可靠性。最后，如果降雨持续，低可靠性区总是在不透水基岩附近。
A first-order moment analysis is developed to investigate the temporal and spatial propagation of uncertainty of slope stability during rainfall, considering spatial variabilities in initial soil water pressure and soil hydraulic properties, and temporal variability of rainfall. Results of the analysis indicate that the uncertainties resulting from variabilities in initial soil pore water pressure distributions and rainfalls are comparable with that from the variability in soil hydraulic properties. Further, the evolution of slope stability uncertainty is driven by the mean flow field, and a localized large-uncertainty zone along the slope profile could form, leading to a localized low-reliability zone, which may lead to the failure of the slope. In particular, when the slope is close to saturation, the reliability of the stability analysis of any elevation of the slope is low even at early rainfall times. On the other hand, when the slope is unsaturated and heavy rainfalls occur, the low-reliability zone exists at shallow parts of the slope at early times. The results also show that greater unreliability exists at shallow depths at early times when the rainfall has a descending trend in comparison with uniform and increasing trend. Lastly, the low-reliability zone is always near the impermeable bedrock if rainfall persists.