Study On Static Liquefaction Characteristics Of Saturated Silt

Landslide disasters cause a large number of casualties and economic losses every year.The static liquefaction of soil slope is always one of the most important reasons for landslide.Taking Yellow River alluvial silt soil as the research object,by means of tri-axial test and numerical simulation,the effect law of consolidation ratio,dry density,confining pressure and moisture content on the static liquefaction of silt soil was studied in this paper.The main contents are as follows:(1)By means of indoor experiments,the basic physical and mechanical indexes of the tested soil were obtained,the plastic index,the maximum dry density and the optimum moisture content of the test soil.(2)By means of indoor consolidated undrained tri-axial test,the static liquefaction characteristics of Yellow River alluvial silt were studied.The effect law of confining pressure,consolidation ratio,dry density and moisture content on the static liquefaction of silt soil was studied.1)With the increase of confining pressure,the liquefaction potential of saturated silt soil would decrease and the maximum pore water pressure would increase.The sliding surface of saturated silt soil under different confining pressures at the same consolidation ratio was obtained from the effective stress path diagram.Under the same stress condition,with the increase of consolidation ratio,the slope of sliding surface would increase.2)With the increase of consolidation ratio,the liquefaction potential and maximum pore water pressure would all decrease.The relationship between consolidation ratio and peak deviator stress/residual strength was concluded to be linear.Based on the effective stress path,the sliding surfaces of saturated silt under different consolidation ratios were obtained.3)The static liquefaction potential of saturated silt would decrease with the increase of dry density.When the dry density was greater than 1.53g/cm~3,the effect of dry density on the static liquefaction potential of silt soil was significantly enhanced and the maximum pore water pressure decreased obviously.The maximum value of pore pressure was approximately linear with the consolidation ratio.4)With the increase of moisture content,the liquefaction potential of saturated silt soil would increase and the maximum pore water pressure would decrease;the branch deviator stress and residual strength of silt soil were all approximately linear with moisture content.(3)The numerical simulation of the soil slope was carried out by using SLOPE/W software.The effect of dry density and water content on the slope stability was studied.The analysis showed that,with the increase of dry density,the safety factor of the slope would increase;the increase of moisture content would have an opposite effect on the safety factor of the slope.