Formation mechanism and distribution of transient saturated areas of residual slope under rainfall conditions
Fu Hongyuan , Shi Zhenning , Zeng Ling
DOI:10.11835/j.issn.1674-4764.2017.02.001
Received May 10, 2016,Revised , Accepted , Available online July 04, 2017
Volume ,2017,Pages 1-10
- Abstract
Rainfall is one of the most common external factors causing the instable residual soil slope. Rainwater infiltration leads to the reduction of the soil shear strength, the increase of the weight of soil and the decrease of the matric suction, so as to cause the slope instability. The study of rainfall infiltration inside the slope has become the precondition of the study of the slope stability under the rainfall condition. Basing on the finite element numerical simulation method, this paper focuses on the simulation of rainfall infiltration process. The present work is emphasized on the formation, distribution and vanishing of transient saturated zone, and characterizes the variation of volume water content, matric suction and the hydraulic gradient inside the slope. The results can be the foundation of the study that the rainfall influences the stability of residual soil slope. The calculation results show that: 1)The major cause of the formation of transient saturated zone is ascribed to the fact that the rainwater exudation under the wetting front is less than the amount of rainfall infiltration, thus increasing the moisture content in the soil; 2)The formation of transient saturated zone, rainfall infiltration depth and the water content of soil surface have close relationship with rainfall intensity and duration. The entire process from the formation, to the development, to the vanishing of transient saturated zone, and to the raise of groundwater level is studied. From the design of slope drainage is worth thinking is indicated.