Discussion the differential equations and numerical calculation of water transference in nsaturated expansive soil

According to the existing theories of soil mechanics and fluid mechanics, as well as the features about the water and soil curves of unsaturated expansive soil. It is obtained the equations about gaseous water transfer and liquid water transfer of unsaturated expansive soil. It is be seen from coefficients in the equation that water migration bringing water content changes relating to moisture gradient, moisture level, temperature, matric suction, as well as soil density and the ratio of the volume. In different soil the water curve parameter is different, then the coefficients of differential equations is also different. As a example calculation using this equation on water content changes caused by gaseous wate migration, gaseous and water mixed migration, we see that the computed results are consistent with the experimental results very well. It is verified that the equation is rational.