Influence of saturation degree and role of suction in unsaturated soils behaviour: application to liquefaction

Abstract

Abstract. The effect of the pore fluid compressibility on liquefaction has been studied by various authors. But few papers have been published about the role of suction in cyclic behavior of unsaturated soils. Most of these works use Skempton coefficient B as a reference in terms of saturation degree to analyze their results. The use of B in experimental conditions is convenient, but is not accurate when studying liquefaction behavior, since effects of suction are neglected. In this paper, the influence of saturation degree on mechanical behavior of a soil under dynamic loads is studied. Cyclic undrained triaxial tests were performed on sand samples, under various levels of saturation. Soil-water characteristic curve was used, in order to study influence of suction. The first results confirm that when the degree of saturation decreases, the resistance increases. Initial positive suction tends to stiffen the soil. It also appears that the presence of air delays the occurrence of liquefaction, but doesn't prevent it. Indeed, liquefaction is observed, whether the soil is saturated or not.

Water Retention and Saturation Degree of Peat Soil in Sebangau Catchment Area, Central Kalimantan

“…For the SP sample, the estimated value of volumetric moisture content is more approach to the measured value, while for the MP and DP sample categories, it has weak proximity to the measured value. The decreasing volumetric moisture content following an increasing pF value for SP more confirm the curve pF pictures by many other types of research, particularly with the water retention study in mineral soil (Rajkai et al 2004;and Vernay et al 2016). The SP can represent the peat soil in hemic decomposition stages, which is more penetrated by fine mineral material (Widjaya-Adhi 1992).…”