Abstract: Dispersive soil wetted in water has dispersivity and likely to cause destruction of dams
and other hydraulic structures. In this work, the dispersivity of clayey soil at the site of Xinjiang
Akedala diversion channel has been studied, using pinhole test, crumb test, double hydrometer test,
pore water soluble salt cation test, and the test of exchangeable sodium ions percentage, with
comparison with an empirical equation for evaluating dispersivity of cohesive soil. The results
show that by the five test methods all the six soil samples are transitional type while by the
empirical equation five samples are transitional and one is dispersive. The two methods give
similar identification results, so it is concluded that all the six samples are transitional soils. These
soil samples contain a large amount of sodium ions, have rather high pH values, indicate strongly
alkaline, which could promote dispersivity. Their high contents of clay and organic matter,
however, lower their dispersivity so that they show transitional characteristics.