THE EFFECT OF RAINFALL ON SOIL METRIC SUCTION
Authors:Nader Alqam, Michael Ayad, Chris Sims
- Binod Tiwari, Associate Professor of Civil Engineering, Cal State Fullerton
- Santiago Caballero, Graduate Student, Cal State Fullerton
Wide spectrums of slope failure have been noted all over the world including Brazil, South Africa, Japan, USA, and Hong Kong. The causes of landslides are usually related to instability caused by earthquakes, rainfall, and anthropogenic reasons. In the recent years, rainfall has been considered one of the main reasons of landslides and has attracted increasing attention around the world. Rainfall leads to soil erosion; an increase in the unit weight as well as the pore water pressure causing reduction in the soil metric suction. This results in a decrease of the soil shear strength causing a loss of equilibrium in the slope leading to failure. To test the effect of the increase in pore pressure, an experiment was conducted on a clayey soil. In order to determine the relation between, intensity of rainfall and soil metric suction, a clay sample was placed on a Plexiglas container at the void ratio of 0.89 and cut to 23°, 35° and 45° slope angles. The slopes were subjected to 18 mm/hour of rainfall using a rain simulator. This presentation includes the effect of intensity and duration of rainfall as well as slope angles on the reduction of soil suction.