Determining the soil-water retention curve using mercury intrusion porosimetry test in consideration of soil volume change

It is well-known that a close link exists between soil-water retention curve(SWRC) and pore size distribution(PSD). Theoretically, mercury intrusion porosimetry(MIP) test simulates a soil drying path and the test results can be used to deduce the SWRC(termed SWRCMIP). However, SWRCMIPdoes not include the effect of volume change, compared with the conventional SWRC that is directly determined by suction measurement or suction control techniques. For deformable soils, there is a significant difference between conventional SWRC and SWRCMIP. In this study, drying test was carried out on a reconstituted silty soil, and the volume change, suction, and PSD were measured on samples with different water contents. The change in the deduced SWRCMIPand its relationship with the conventional SWRC were analyzed. The results showed that the volume change of soil is the main reason accounting for the difference between conventional SWRC and SWRCMIP. Based on the test results, a transformation model was then proposed for conventional SWRC and SWRCMIP, for which the soil state with no volume change is taken as a reference. Comparison between the experimental and predicted SWRCs showed that the proposed model can well consider the influence of soil volume change on its water retention property.