降雨和库水位升降条件下考虑非饱和渗透系数空间变异的边坡可靠度分析  

Reliability analysis by considering spatial variability of unsaturated hydraulic conductivity under rainfall and reservoir water level fluctuation

作　　者：柳伟 徐长节[1,3] 胡世韬[4] 朱怀龙 LIU Wei;XU Changjie;HU Shitao;ZHU Huailong(Jiangxi Key Laboratory of Infrastructure Safety Control in Geotechnical Engineering,East China Jiaotong University,Nanchang 330013,P.R.China;Jiangxi V&T College of Communications,Nanchang 330013,P.R.China;Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,P.R.China;School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,P.R.China)

机构地区：[1]华东交通大学江西省岩土工程基础设施安全与控制重点实验室,南昌330013 [2]江西交通职业技术学院,南昌330013 [3]浙江大学滨海和城市岩土工程研究中心,杭州310058 [4]上海大学力学与工程科学学院,上海200444

出　　处：《土木与环境工程学报（中英文）》2024年第3期61-72,共12页Journal of Civil and Environmental Engineering

基　　金：国家杰出青年科学基金(51725802);江西省交通运输厅科技项目(2021H0037)。

摘　　要：降雨和水位升降对库岸边坡具有显著影响,传统确定性分析难以准确评估其稳定性。考虑降雨和水位升降联合作用下水力参数的空间变异性,进行非饱和土边坡可靠度分析具有重要意义。以赣江库区中的莒洲岛边坡为研究对象,以贝叶斯方法校准的多元水力参数的联合随机场为基础,建立非饱和土边坡的稳定性分析方法。根据有限的岩土力学室内试验数据,采用贝叶斯方法校准土水特征曲线的模型参数,并从VGM、VGB、VG和FX模型中选出最优模型;联合多元水力参数的随机统计特征,生成非饱和土边坡渗透系数的随机场空间分布;针对2021年5月赣江水位快速升降并伴随暴雨的工程背景,将上述方法应用于莒洲岛库岸边坡的稳定性分析。研究结果表明,暴雨与水位变化的联合作用对边坡安全系数的影响显著,确定性分析的边坡安全系数偏低,考虑非饱和渗透系数空间变异性后计算所得到的SWCC综合可靠指标不能满足规范要求,需采取额外的边坡工程加固措施以保证边坡的长期稳定性。The geotechnical parameter of soil mass in colluvial landslide is uncertain.Saturated hydraulic conductivity and soil-water characteristic curve(SWCC)are important parameters for the unsaturated seepage analysis.It is of great significance to carry out the reliability analysis of reservoir bank landslide considering the spatial variability.In this study,the Jvzhoudao slope in the Ganjiang Reservoir Area is investigated as a case.Firstly,according to the limited laboratory test data of saturation-matrix suction,the statistical characteristics of the SWCC properties,such as VGM,VGB,VG,and FX model parameters are calibrated by the Bayesian method,and the applied probabilities of SWCC model combination are determined by the laboratory measurements.Secondly,combining the random field characteristics of the saturated hydraulic conductivity with the random characteristics of the SWCC models,spatial distributions of the unsaturated hydraulic conductivity are generated in the slide body.Finally,for the extreme conditions in the Ganjiang Reservoir Area in May 2021,the proposed method was applied to the case stability analysis.Results indicate that the combined effect of rainstorm and water level change has a significant impact on the safety factor,and that the safety factor of the deterministic analysis is low.Reliability index calculated after considering the spatial variability of the unsaturated permeability coefficient cannot meet the specification requirements,while additional slope engineering reinforcement measures should be taken to guarantee the long-term stability of the slope.

关 键 词：库岸边坡 土水特征曲线 非饱和渗透系数 贝叶斯方法 可靠度分析 

分 类 号：TU43[建筑科学—岩土工程]