A STUDY OF MEASUREMENT OF SOIL SUCTION AND SOIL WATER CHARACTERISTIC CURVE OF UNSATURATED SOILS

Abstract

Unsaturated soil mechanics is an important topic to deal with at the post graduate level because textbooks cover the theories related to soils in a completely dry or a completely saturated condition. Recently, it has been shown that attention must be given to soils that do not fall into these common categories. Many of these soils can be classified as unsaturated soils. As a geotechnical expert, we have to encounter soils which are in a state of partial saturation. And it becomes necessary to understand the basic behavior of these kinds of soils in order to carry out any construction activity on them. Engineering related to unsaturated soils has typically remained empirical due to the complexity of their behaviour. An unsaturated soil consists of more than two phases and therefore the natural laws governing its behaviour are changed and the principle of soil suction comes into action. So, a basic understanding about the concept of soil suction, its components, its representation, various methods with their relative advantages and limitations and a detailed description of filter paper method to measure soil suction has been presented in this report. An experimental setup has been designed which can be used in the laboratory. The procedure to obtain a calibration curve required to obtain the results has also been provided, along with the models of various researchers to obtain soil water characteristic curve and unsaturated hydraulic conductivity. The effect of compaction on these parameters has also been dealt with.