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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2022 Vol.23 No.3 P.208-224
A comparison study between 2D and 3D slope stability analyses considering spatial soil variability
Abstract: In engineering practice, the stability of a slope is often analyzed as a 2D problem assuming a plane-strain condition, which may lead to significant errors. In this paper, a comprehensive study is carried out to compare the results of 2D and 3D slope stability analyses, using the strength reduction method for deterministic analysis and the random field approach for probabilistic analysis, respectively. The results of this comparison study confirm that in the deterministic stability evaluation, the 2D analysis tends to obtain a smaller factor of safety than does its 3D counterpart. In the probabilistic evaluation that considers the spatial variability of soil properties, the 2D analysis tends to yield a larger probability of failure than its 3D counterpart. A significant feature of the 3D probabilistic slope stability analysis is the presence of multiple local failures distributed along the slope longitudinal direction. This paper provides insights regarding the degree of errors in modeling a 3D slope as a 2D problem, which can be regarded as a complement to the previous 3D slope stability analyses.
Key words: Slope stability; Spatial variability; Probability of failure; Factor of safety; Longitudinal length
机构：1中国地质大学（武汉），工程学院，中国武汉，430074；2合肥工业大学，资源与环境工程学院，中国合肥，230009；3哥伦比亚特区大学，土木工程学院，美国华盛顿哥伦比亚特区，20008
目的：传统边坡稳定性评价通常基于典型横断面进行二维分析，忽略了边坡纵向长度对稳定性评价的影响。本文旨在研究两种边界条件下三维边坡稳定性分析和二维边坡稳定性分析结果的差异性及其原因，并探究土体参数水平波动范围和边坡纵向长度对边坡稳定性的影响规律。
创新点：1.从确定性和不确定性分析两个角度对比研究二维和三维边坡稳定性分析结果的差异性；2.揭示土体参数水平波动范围和边坡纵向长度对三维边坡稳定性的影响规律；3.分析三维边坡失稳的局部破坏统计特征。
方法：1.运用数值模拟方法，采用强度折减法分析计算边坡安全系数（公式(1)）；2.通过蒙特卡洛和矩估计法计算边坡失效概率（公式(9)~(12)）。
结论：1.确定性分析结果表明，全约束RR型边界条件下三维边坡稳定性分析结果更符合真实条件下边坡破坏形态；半约束SS型边界条件下三维边坡稳定性分析可视为二维边坡稳定性分析方法在边坡纵向长度的延展。2.考虑土体参数空间变异时，三维边坡稳定性分析得到的失效概率通常小于二维边坡稳定性分析计算结果，二者间的差异性在一定范围内随边坡纵向长度和土体参数水平波动范围增加而减小。3.考虑土体参数空间变异时，三维边坡稳定性分析会得到沿边坡纵向的多个局部破坏，这些局部破坏可很好地解释二维和三维边坡稳定性分析结果的差异性。
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DOI:
10.1631/jzus.A2100139
CLC number:
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On-line Access:
2022-03-18
Received:
2021-03-31
Revision Accepted:
2021-08-16
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