Evaluation of swell behaviour of expansive clays from specific moisture capacity

The University of Texas at Arlington, Department of Civil Engineering, Arlington, Texas 76019 USA

^a Corresponding author: alejandro.pinobravo@mavs.uta.edu

Abstract

Current swell characterization techniques used to interpret the mechanical volume change occurring during the swelling process are not successful due to lack of inclusion of influential properties. Accurate prediction of swelling behaviour allows us to design more efficiently and with better reliability. This research aims at developing a more comprehensive framework to predict swell potential. Laboratory studies are conducted on five natural expansive soils with different degree of expansiveness. Initial studies include determination of basic soil characterization, swell strains and swell pressures at their compacted state along with their inherent mineralogy. Later, replicate samples were studied for soil water characteristic curves using standard pressure cell apparatus and filter paper techniques. The path traversed by the specimen during swelling process is representative of the soil water characteristic curve of the same specimen. Hence, studies are pursued to understand the relationship between degree of expansiveness and the specific moisture capacity relative to that particular range of suction head. Test results showed that the degree of expansion represented by swelling strain or swelling pressure is proportional to the specific moisture capacity determined during the swelling process.