Research On Liquefaction Evaluation Criteria For Silty Soil In Yellow River Delta

The silty soil in Yellow River Delta have unique liquefaction character , and there is not the uniform liquefaction evaluation. In this paper, dynamic triaxial tests have been carried out in order to establish liquefaction evaluation criteria for silty soil in the Yellow River Delta, for studying the changes of pore water pressure and dynamic shear strain, and then establish the initial liquefaction evaluation criteria, influence of clay content, initial stress ratio, and initial dry density on initial liquefaction evaluation criteria are studied. Then Numerical simulation has been done to validate the initial liquefaction evaluation criteria. At last, the consolidated and undrained triaxial tests have been carried out in order to establish the steady state strength line of silty soil in this delta. This paper drew some conclusions as follows:(1) If the pore water pressure of Yellow River delta can approach the effective confining pressure, then the pore water pressure ratio 1 is considered as the initial liquefaction evaluation criteria. If not, study changes of pore water pressure, the pore water pressure ratio when pore water pressure become steady is considered.(2) The pore water pressure is appropriate to be the initial liquefaction evaluation criteria when clay content is low, the pore water pressure ratio 0.8 and the strain 6% are considered when the clay content between 14% and 24%, and when the clay content is more than 24%, the strain 6% is considered. Initial stress ratio have no effect on liquefaction evaluation criteria of stain, but have effect on the criteria of pore water pressure, the failure pore water pressure ratio decrease when Initial stress ratio increase.(3) The result of liquefaction evaluation of Numerical simulation with the initial liquefaction evaluation criteria is similar to the standard penetration test and static cone penetration test.(4) The steady state line of silty soil in Yellow River delta is shown as e=m(C_clay)+n(C_clay)lgτ, in which: and eontent.