Experimental Study on Property of Foamed Lightweight Soil Mixed with Silty Clay
To solve the problem of engineering waste soil reuse,the foamed lightweight soil is mixed with silty clay.The effects of silty clay content,wet density,curing age,and foam content on the flow value and compressive strength of foamed lightweight soil materials are analyzed.The microstructure of foamed lightweight soil is observed by using SEM,and the relationship between macro-property and microstructure is analyzed.The result indicates that the flow value of foamed lightweight soil decreases with the increase of silty clay content with the same water solid ratio.With the same soil content,the flow value increases with the increase of initial wet density.Reasonably control the dosage and initial wet density of silty clay can ensure good fluidity and stability during construction.When the water-solid ratio is 0.75,the content of silty clay increases,while the flow value of foamed lightweight soil decreases.The lightweight soil with wet densities of 700 kg/m3 and 800 kg/m3 still show good fluidity at 50%content.The compressive strength decreases with the increase of silty clay content,and increases with the increase of initial wet density.With 33%content of silty clay and 0.75 water-solid ratio,the 7 d compressive strength of lightweight soil with wet densities of 700 kg/m3 and 800 kg/m3 both exceed 1.0 MPa,meeting the construction requirements of roadbed.With the increase of foam content,the wet density,flow value and compressive strength of foamed lightweight soil decrease,and the internal porosity increases.Through observing the microstructure,it is found that the good porosity structures(e.g.,complete and independent pores,uniform distribution,large pore wall thickness,and spherical shape)can enhance the structural compactness of foamed lightweight soil.Adding silty clay and foam can affect the porosity integrity,leading to the deterioration of macro-property of foamed lightweight soil.
NETL
NSTL
万方数据
