Rate of capillary rise in soil

A rigorous closed-form analytical solution is developed for analyzing the rate of capillary rise in soils. The new solution can be reduced to Terzaghi's classical solution if the nonlinearity in the hydraulic conductivity with changing soil suction is ignored. Results obtained using the new solution are compared with Terzaghi's classical solution and a series of previously documented experimental data from open-tube capillary rise tests. The new solution is a significant improvement over the previous solution, thus providing more realistic and practical predictions for the rate of capillary rise in unsaturated soils.