Soil Suction‐Potential Model

A suction‐potential model based on the diffusion equation is proposed whereby the suction is predicted at all times and depths in terms of a parameter K and the initial values of suction ${\beta }_0$ The model shows that the suction ratio decays exponentially with time. The exponential decay rate is not uniform throughout the expansive soil, but it increases with decreasing distance to the water source. Analysis reveals that the prediction error will not exceed 25% even if K value increases by 100%, suggesting the validity of the model in providing an adequate means for suction determination. Furthermore, close agreement is found between laboratory observations and the theoretical behavior. However, the theoretical estimate of the average suction potential does not agree well with the field observation. The discrepancies may be attributed to the heterogeneities of the soil and to the simplified boundary conditions adopted in the theoretical model.