Characteristic of Unsaturated Soil of Earth Fill Dams in Vietnam

Abstract

In Vietnam, earth dams are generally used with in-situ soils having low clay content (especially earth dams at the central part of Vietnam). The knowledge, experience, theory for calculation, apparatus for unsaturated soils in Vietnam are still very limited, especially the studies of the influences of the shear strength of unsaturated soils to the stability of earthen structures. Therefore, the research to study the soil-water characteristic curve, shear strength and coefficient of permeability versus different matric suction on Vietnamese soil is an urgent issue and it has big scientific and practical meaning. This research shows that when the matric suction in the soil changes, the effective cohesion c’ would change, however the internal friction angle, f’, is almost unchanged for some type of soil in Vietnam. The experimental results would be applied to study the affect of unsaturated soil to the factor of safety of the slope.