Clogging Characteristics Of Dredged Soil Considering Non-Uniform Consolidation And Horizontal Deformation

For many years,prefabricated vertical drains(PVDs)combined with vacuum preloading drainage consolidation is used in the foundation treatment of dredged clay in eastern coastal areas of China.Due to the high water content of dredged clay,the soil at different locations away from the PVDs produces non-uniform settlement and obvious "clogging" phenomenon around the PVDs.Therefore,the study on soil non-uniformtiy around PVDs can help consolidation theory of soil,but also have important value in engineering application.(1)In order to study the clogging effect caused by the non-uniform consolidation of dredged clay under vacuum preloading,a series of laboratory model tests were designed.The consolidation characteristics of dredged clay at different distances from pervious stones were compared and studied through a series of one-dimensional consolidation tests.The test was divided into four working conditions,corresponding to four different initial conditions.In the first case,the soil samples with different initial water content are obtained by remolding method.In the second case,the soil samples with different initial salt content are obtained by washing salt and adding salt.The third condition is to use different vacuum pressures to test,and the influence of vacuum on the stability of soil is analyzed by Ruth theory.The test results show that the lower vacuum pressure is helpful to form a stable filter layer near the drainage boundary.Then,Terzaghi consolidation theory and layered soil consolidation theory are combined to consider the change of permeability caused by non-uniform consolidation in the clogging layer.It is concluded that the consolidation model proposed is more similar to test date.(2)In addition,Plaxis 2D numerical simulation software is used to simulate the laboratory model test of vacuum preloading.Under different initial moisture content and different loading modes,the settlement andhorizontal deformation of soil are studied,and the clogging effect caused by different horizontal deformation of soil after consolidation is obtained.(3)Finally,Plaxis is used to simulate and analyze the different conditions of vacuum preloading.By changing the parameters of soil,the initial stress and different vacuum loading conditions are applied to obtain the distribution of the horizontal strain,so as to judge the influence on the clogging effect.