Difference and Relationship of Elements in the Issue of Seepage and Consolidation

There are many researches on the seepage and deformation of saturated soil. However, the calculated soil settlement deformation, based on the existing seepage and consolidation model, is not consistent with the observed ones. These issues derived from the seepage and consolidation equations based on different elementary volumes. This article investigates the basic element constitution in the derivation of differential equations, from the origination of the seepage and consolidation equations of saturated soil. It is found that the seepage and consolidation equations of saturated soil are based on different elementary volumes, namely the elementary control volume with constant volume and elementary deformation volume with varied volume. The difference and relationship of these two elementary volumes and the seepage and consolidation equations are analyzed. The relationship equation of these two parameters is provided. It reveals that the coefficient of consolidation and hydraulic diffusivity are parameters with different physical meaning and values. The relationship of these two parameters is provided. The observed land subsidence and calculated ones based on consolidation equation under the condition of releasing water are compared. The accuracy of the quantitative relationship between coefficient of consolidation and hydraulic diffusivity is discussed using experimental data.