考虑网格自适应的边坡可靠性随机有限元极限分析研究  

Slope Reliability Analysis Based on Grid Adaptive FELA

作　　者：许晓亮[1] 张家富 曾林风 徐健文 史为政 XU Xiaoliang;ZHANG Jiafu;ZENG Linfeng;XU Jianwen;SHI Weizheng(Key Laboratory of Geological Hazards in Three Gorges Reservoir Area(China Three Gorges Univ.),Yichang 443002,China)

机构地区：[1]三峡库区地质灾害教育部重点实验室(三峡大学),湖北宜昌443002

出　　处：《三峡大学学报（自然科学版）》2022年第6期48-57,共10页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金(51979151);国家自然科学基金(51809151);水利部水库大坝安全重点实验室开放基金(YK321012)。

摘　　要：在有限元极限分析(finite element limit analysis, FELA)的基础上,结合随机场理论,提出了网格自适应的边坡可靠性随机有限元极限分析方法,探讨了网格自适应前后的FELA法的确定性和可靠性分析结果,重点针对网格自适应FELA方法,从安全系数均值、分布规律及可靠度指标、潜在滑移面分布等角度分析了岩土参数变异系数和波动范围的影响.结果表明:考虑网格自适应的FELA能有效搜索潜在滑移面,在获得严格上、下限解的同时可显著提高边坡可靠性分析效率;通过随机场刻画参数变异特性能降低传统确定性分析对边坡稳定性的过高估计.随着变异系数的增大,安全系数概率密度曲线整体向左偏移,安全系数均值下降但变异性增大,坡体可靠度指标减小,坡体潜在滑面的分布更为离散;随着波动范围增大,出现了坡体安全系数均值增大但可靠性指标减小的互斥现象.相比黏聚力变异系数和水平波动范围,边坡可靠性分析结果对内摩擦角变异系数和竖向波动范围更为敏感.Based on finite element limit analysis(FELA) and combined with random field theory, a random finite element limit analysis method for slope reliability with grid adaptation is proposed. The deterministic and reliability analysis results of the FELA method before and after grid adaptation are discussed. Focusing on the grid adaptive FELA method, the influence of the coefficient of variation and fluctuation range of geotechnical parameter is analyzed from the perspectives of mean safety factor, distribution law and reliability index, and potential slip surface distribution. The results show that FELA, which considers mesh adaptation, can effectively search for potential slip surfaces, and can significantly improve the efficiency of slope reliability analysis while obtaining a strict upper and lower limit solution. Traditional deterministic analysis ignores the spatial variability of geotechnical parameters, which causes overestimation of slope stability, and the parameter variation characteristics depicted on the ground are significantly affected by the slope reliability analysis results. With the increase of the coefficient of variation, the probability density curve of the safety factor is shifted to the left as a whole, the mean safety factor decreases but the variability increases, the reliability index of the slope decreases, and the distribution of the potential slip surface of the slope is more discrete. With the increase of the fluctuation range, the mutually exclusive phenomenon of increasing the average safety factor of the slope body but decreasing the reliability index appears. Compared with the coefficient of variation of the cohesion and the horizontal fluctuation range, the slope reliability analysis results are more sensitive to the coefficient of variation of the internal friction angle and the vertical fluctuation range.

关 键 词：岩土参数变异性 随机场 有限元极限分析 网格自适应 滑移面 可靠性分析 

分 类 号：TU43[建筑科学—岩土工程]