Influence of Soil Type and Placement Conditions on Soil Suction in Compacted Expansive Soils

Abstract

This study investigates the influence of the type of soil, compaction moisture content and dry density on soil suction in impact compacted expansive soils. Many samples which were obtained from five highly expansive soil types were tested. The soil types considered in this study included two natural from Sudan and three natural/artificial soil mixtures. An apparatus based on the axis-translation technique of suction measurement was developed and successfully used for laboratory testing. From analysis of the study results, it was concluded that for a given soil the suction is strongly influenced by the moisture content. The study also showed that at given moisture content, more plastic soils tend to yield greater suction values than less plastic soils. An empirical equation was proposed to relate soil suction, moisture content and soil type. The suction dry density relationship was investigated for samples from the two natural soils only and the trends obtained indicate that the influence of the dry density on soil suction is of secondary importance.