Research On Dynamic Properties Of Hangzhou’s Saturated Silty Sands Under Metro Vibration Loading

This article takes typical saturated silty soil around Hangzhou metro as object of research which is based on domestic and foreign working, analyses it’s dynamic properties under metro vibration loading with the help of dynamic triaxial experiment and mathematical model fitting. The main working of this article is as follow.(1) Through refering to relevant literature, the research status of silty soil’s liquefaction and the pore water pressure model under circular vibrating loads is summarized.Research status of accumulated deformation of the saturated silty soil under long-term load and the traffic load characteristics are summarized.(2)By dynamic strength test of saturated silty soil, the applicable conditions of several classic failure criteria under different test conditions is comparised. Different vibration frequency, different consolidation ratio, and different confining pressure effect on the dynamic strength of the soil are analysed.(3)By large number of indoor dynamic triaxial test,curves of development dynamic pore pressure under equipressure consolidation and anisotropic consolidation with different frequency and different confining pressure are concluded.The characteristics and fitting effect of zhang jianmin’s type A curve,improved curve of zhang jianmin’s type A,and hyperbolic model is comprised.The defects of existing models are improved.The pore pressure growth models of saturated silty sands are created,and the model parameters are determined.(4) Through the test of cumulative plastic deformation of soil under long-term cyclic vibration load, curves of relationship between the dynamic strain and the number of vibration under different confining pressure and different stress ratio are analysed. The critical dynamic stress ratio is discussed.Fitting effect of the index model based on Monismith and semi-log model for soil cumulative plastic strain is contrastively analysed.The applicability of the model is verified.And related parameters of soil suitable for this paper are achieved.The influencing factors in the semilog model which impact on parameters of prediction model of cumulative plastic strain development are determined.Then regulation of cumulative plastic strain of soil under the long-term cyclic vibration load is deeply studied.