Permeability And Mechanical Behaviours Of Stabilized Silt By Inorganic Soil Stabilizer

The flooded area of Yellow River,that is,the Yellow River flood area,whose soil layer is formed by repeated erosion and sedimentation of the old and new alluvial of the river.Therefore,the silt soil in this area has the characteristics of relatively concentrated particle size,high roundness of soil particles,high permeability and low strength.when the silt is used as the foundation or roadbed filling,engineering problems such as insufficient bearing capacity and poor stability often occur.Zhengzhou is an important part of the flooded area of Yellow River,so the silt in this area also has the corresponding soil properties of the flooded area of Yellow River.Therefore,it is often necessary to improve or treat the silt in Zhengzhou in order to solve the above engineering problems.In order to improve the engineering properties of the silt in Zhengzhou,a new inorganic soil stabilizer is used in this paper,the permeability and mechanical properties of the improved silt in Zhengzhou are explored through penetration test and triaxial consolidated-undrained shear test.In order to facilitate engineering application,based on the test results,mathematical model suitable for predicting the permeability changes of solidified silt and a model capable of describing its constitutive relationship are found.the following conclusions are obtained:(1)The results of the penetration test show that increasing the mixing ratio of soil stabilizer and prolonging the age can reduce the permeability of solidified silt.Moreover,when the mixing ratio of soil stabilizer is greater than 15%,as the mixing ratio increases,the degree of permeability of solidified silt decreases gradually.In addition,compared with within 60 days of the age,when the age exceeds 60 days,prolonging the age,the degree of permeability of solidified silt also decreases gradually.(2)The results of consolidated-undrained shear test show that the stress-strain curve of solidified silt shows obvious feature of strain softening.At the same time,the influence of changes in the mixing ratio,confining pressure,and age on the peakstress and residual stress of solidified silt is consistent,that is,with the increase of the mixing ratio,confining pressure or age,the peak stress and residual stress of the solidified soil will increase during the shearing process.In addition,when the age exceeds 60 days,with the extension of age,the shear strength of the solidified silt still increases,but the degree of increase will gradually slow down.(3)The characteristics of the pore water pressure curve of the solidified silt during shearing process indicate that the larger the confining pressure,the larger the peak of pore water pressure,but increasing the mixing ratio and prolonging age have no significant effect on the peak of pore water pressure.In addition,when the confining pressure increases,the pore water pressure coefficient in the peak stress state and the residual stress state will increase,furthermore,the larger the confining pressure,the more difficult it is for negative pore water coefficient to appear.In contrast,the larger the mixing ratio and the longer the age,the more easily the pore water pressure coefficient becomes negative.(4)The results of the one-dimensional compression test show that the silt in Zhengzhou improved by the soil stabilizer has strong structural properties.Based on this,the unified hardening(UH)model considering bonding in structured soils is introduced to describe the constitutive relationship of solidified silt.Furthermore,the simulation of the results of consolidated-undrained shear tests shows that the model is qualified in describing the behaviors of the solidified silt in undrained triaxial compression.