Strength and stress-water content-strain relationship of unsaturated soil is studied experimentally. Firstly
strength and deformation tests are done
which simulate the project characteristic that pore air pressure dissipates very quickly and water pressure does not. Secondly
a total stress strength formula is suggested by researching the relationship between the strength and water content. Finally
a nonlinear model is presented on the basis of the relationship between the parameters under different values of constant water content. A case study shows that the model is reasonable. The use of the theories of unsaturated soil has been limited because of the difficulties in measuring and calculating suction. The presented approach
choosing water content which can be gained easily in project