One-Dimensional Rheological Consolidation Of Saturated Clays

Although Terzaghi’s one-dimensional consolidation theory is widely used, there sometimes exits notable difference between the solution of consolidation of saturated clay layers based on this theory and the field settlement observations,which may be in a certain extent ascribed to not considering the rheological properties and non-darcy flow influence on consolidation. By using modified device,the rheological properties and flow characteristics of a kind of saturated clay in Henan is studied carefully,and considering the coupling effect of primary and secondary consolidation, Terzaghi’s one-dimensional consolidation equation is modified. The main original work includes:Firstly, the improvement test device of one dimensional rheological consolidation is introduced briefly, by using the modified osmotic oedometer, the consolidation and permeability tests can be successively carried out. Based on this device, the one-dimensional rheological consolidation and permeability tests of saturated clays which accord with Darcy’s law in Henan are carried out,measuring the pore water pressure.The result shows that the flow in this soil obey Darcy’s law and void ratio and the logarithm of permeability coefficient can approximate linear relationship.What’s more,it also shows that the coefficient of secondary consolidation of this soil is related to consolidation pressure. When the consolidation pressure is equal to200kPa, the secondary consolidation coefficient reaches the maximum.At the same time the test also find that pore water pressure hysteresis.Then the modified linear relationship between the change of void ratio and the logarithmic time proposed by Yin Zongze(2003) was introduced to simulate the rheological behaviors in the consolidation process of normally consolidated and saturated clays. Terzaghi’s one-dimensional consolidation equation was modified, respectively considering the influence of Darcy flow and non-Darcy flow, and numerical analysis was performed by using the finite volume method.Accordingly the effects of rheological parameters on the one-dimensional consolidation process of normally consolidated soils were investigated. The numerical results indicated that the rheological behaviors of these soils delays the consolidation rate of these soil layers, and the phenomenon similar to the Mandel effect appears that the excess pore water pressure increases in the place far away from the drainage boundary at the beginning of loading. In addition, the loading value can also influence the rheological consolidation behaviors of these soil layers.