Experiment Study On Nonlinear Creep Characteristics And Long Term Strength Of Two Kinds Of Soft Soil

With the rapid development of economy construction in our country, someengineering project has to be built in soft soil. Soft soil is widely distributed in ourcountry especially in coastal areas. Soft soil has poor mechanical properties andsignificant creep characteristic because of high water content and void ratio. Creep ofsort soil can lead to increasing settlement and a variety of damage as well as losingfunction of engineering. Especially for the highway, railway and undergroundengineering, the harm caused by soft soil creep is particularly significant. Therefore itis necessary to carry on intensive study on creep of soft soil.Based on two different kind of soft soil, study of soft soil creep process is carriedon in this paper. According to soil mechanics, a series of experiments on physical andmechanical properties of soft soil are carried out. furthermore, for the sake of studyingcreep characters, consolidation creep experiments and direct shear creep experimentsare carried out as well. Based on the result of experiments, creep model andcalculation model of long term strength of soft soil are established in this paper.Based on the experiment result on physical and mechanical of two kinds of softsoil, Tianjin soft soil is more typical than Suzhou soft soil as we as Tianjin soft soilhas worse mechanical properties. The coefficient of viscosity increases first and thendecreases along with the increasing shear stress. Standard liner model is used in Linerviscosity-elastic part of Tianjin soft soil stress-strain relationship and the fourelements Murayama Kitaro model is used in liner viscosity-plastic part. GeneralizedKelvin model is used in viscosity-elastic part of Suzhou soft soil stress-strainrelationship and V/K-H model is used in liner viscosity-plastic part. Empirical is usedin nonlinear viscosity-plastic part of two kinds of soft soil. The stress-strainrelationship established via above method is reasonable and applicable. Based on the point of inflection on creep curve, long term strength index of two kinds of soft soilcan be obtained.