Water stability of Xiangjing expansive soils and their mechanical effect

The evolution characteristics of unconfined compression strength of intact sample at different stages of dehydration and the swelling-shrinkage behavior and its mechanical effect of compacted sample for expansive soils in Xiangjing Expressway, Hubei province are investigated in this paper. It is discovered that the engineering behavior of intact samples is controlled by the coupled action of water content and fissures, in which the coupled degree varies with the fissuring growth and swelling potential of the expansive soils, while the variation of California Bearing Ratio (CBR) of the expansive soils with water content is similar to the compaction curve. However, the water content of soil with the maximum CBR is higher than the optimum water content,therefore, the degree of compaction and CBR value can not reach the maximum at the same time, and the CBR value depends on the water content, dry density and structural state after soaking expansion of the compacted expansive soils. In the construction of expansive soil embankment, the influence of total swell-shrink ratio should be considered besides the degree of compaction and CBR value, and it is helpful to understand the engineering properties of expansive soils.