Re-search Shrink-Swell Measurement and Relationship with Soil Properties of Black Clayey Tropical Vertisols

Shrink-swell phenomenon is a complex process in vertic group of soils. Their dynamics in soils has long been presented through various models, field and laboratory methods. The present study finds out a feasible way to measure the shrink-swell potential and the key responsible factors in soil which are most influentialin determining this phenomenon. Four shrink-swell parameters such as coefficient of linear extensibility(COLE), coefficient of linear shrinkage (COLS), percent volume change on swelling(PVCsw), percent volume change on shrinkage (PVCs) measured at 25°C (room temperature, RT), 40°C and 110°C were used to quantify shrink-swell phenomenon. Results indicated that heating the soil cake at 110°C over 40°C does not bring higher change (0–10%) in linear shrinkage, the corresponding value for volume change at 110°C showed greater change (3–61%) hence, COLS at 40° and PVCs at 110° amongst others were promising and may be recommended for routine measurement of shrink-swell phenomenonin the laboratory. Out of three the different measurement devices, cube shaped box appeared to be the better option. The soil properties which representcarbon content and soil substrate have significant correlations(p<0.01, p<0.05) with the corresponding shrink-swell parameters. The multiple regression analysis showed 69 percent variation for PVCs 110° and 63 percent for COLS 40°.