Nonlinear Consolidation Behaviours Of Saturated Clays Based On Non-Darcian Flow

The saturated cohesive soil is widely distributed in our country,and its deformation has obvious rheological property,and the seepage of water between clay particles often deviates from Darcy’s law.Therefore,it is often difficult to accurately predict the settlement of foundations with this type of soil as the main stress layer.At the same time,the process of construction also affects the permeability of the soil layer,which affects the settlement prediction of the foundation.In order to predict the settlement process of cohesive soil more accurately,this paper further studies some laws of saturated cohesive soil through laboratory tests,including the consolidation law,the rheological property and the seepage property.Considering these factors comprehensively,this paper presents corresponding consolidation analysis models,and the laws of consolidation and settlement for saturated cohesive soil foundations in one-dimensional,vertical drain,and plane strain states are discussed using the above models.The conclusions are as follows:(1)In this paper,the seepage process of the two kinds of test soil deviates from Darcy’s law,and the test results can be described by the Hansbo seepage equation.At the same time,the consolidation test shows that the above two kinds of soil have significant rheological characteristics.In order to describe its rheological property,introducing the hyperbolic relationship between the secondary consolidation coefficient and the logarithm of time,this paper presents the UH constitutive model considering the nonlinear rheology.(2)In the initial stage of consolidation,the phenomenon of rising excess pore water pressure is discovered in one-dimensional,vertical drain,and plane strain states.Moreover,the effect of rheology is the main reason for this phenomenon.In addition,the larger the parameters including the initial over-consolidated parameter,the parameters of non-Darcian flow and the parameter reflecting the anisotropy of seepage flow,the smaller the parameters including the interface parameter,the length of vertical drain,the pave rate and the ratio of thickness-width,the more obvious the above phenomenon.(3)Compared with the completely permeable boundary,the continuous drainage boundary condition slows down the consolidation process of the foundation.And,the smaller the interface parameter,the slower the process of consolidation.After ignoring this condition,the rate of foundation consolidation will be overestimated.When analyzing the settlement,the change of the parameter has no effect on the final settlement of consolidation.(4)Compared with the flooded drainage boundary,the rate of foundation consolidation slows down after the application of distributed drainage boundaries.However,as the pave rate increases,the drainage capacity of the distributed drainage boundary will approach the flooded drainage boundary.In addition,when the pave rate reaches a certain level,the distributed drainage boundary can achieve the purpose of drainage and resource conservation.(5)When analyzing the settlement,the greater the rheological parameter,the initial over-consolidated parameter and the thickness of the soil layer,the greater the final settlement of the foundation.However,considering the influence of the self-weight factor on the initial stress state,the final settlement of the foundation becomes smaller.