Coupled hydro-mechanical analysis of slope under rainfall using modified elasto-plastic model for unsaturated soils
来源期刊：中南大学学报(英文版)2015年第5期
论文作者：WANG Liu-jiang LIU Si-hong FU Zhong-zhi LI Zhuo
文章页码：1892 - 1900
Key words：unsaturated soils; modified basic Barcelona model (BBM); numerical analysis; rainfall infiltration; model slope
Abstract: Two modifications for the basic Barcelona model (BBM) are present. One is the replacement of the net stress by the average skeleton stress in unsaturated soil modeling, and the other is the adoption of an expression for the load-collapse (LC) yield surface that can match flexibly the normal compression lines at different suctions. The predictions of the modified BBM for the controlled-suction triaxial test on the unsaturated compacted clay are presented and compared with the experimental results. A good agreement between the predicted and experimental results demonstrates the reasonability of the modified BBM. On this basis, the coupled processes of groundwater flow and soil deformation in a homogeneous soil slope under a long heavy rainfall are simulated with the proposed elasto-plastic model. The numerical results reveal that the failure of a slope under rainfall infiltration is due to both the reduction of soil suction and the significant rise in groundwater table. The evolution of the displacements is greatly related to the change of suction. The maximum collapse deformation happens near the surface of slope where infiltrated rainwater can quickly reach. The results may provide a helpful reference for hazard assessment and control of rainfall-induced landslides.
WANG Liu-jiang(王柳江)1, LIU Si-hong(刘斯宏)1, FU Zhong-zhi(傅中志)2, LI Zhuo(李卓)2
(1. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China;
2. Nanjing Hydraulic Research Institute, Nanjing 210029, China)
Abstract:Two modifications for the basic Barcelona model (BBM) are present. One is the replacement of the net stress by the average skeleton stress in unsaturated soil modeling, and the other is the adoption of an expression for the load-collapse (LC) yield surface that can match flexibly the normal compression lines at different suctions. The predictions of the modified BBM for the controlled-suction triaxial test on the unsaturated compacted clay are presented and compared with the experimental results. A good agreement between the predicted and experimental results demonstrates the reasonability of the modified BBM. On this basis, the coupled processes of groundwater flow and soil deformation in a homogeneous soil slope under a long heavy rainfall are simulated with the proposed elasto-plastic model. The numerical results reveal that the failure of a slope under rainfall infiltration is due to both the reduction of soil suction and the significant rise in groundwater table. The evolution of the displacements is greatly related to the change of suction. The maximum collapse deformation happens near the surface of slope where infiltrated rainwater can quickly reach. The results may provide a helpful reference for hazard assessment and control of rainfall-induced landslides.
Key words:unsaturated soils; modified basic Barcelona model (BBM); numerical analysis; rainfall infiltration; model slope
