【摘要】 首先通过对现有土体动力反应分析方法的系统分析,在动三轴仪上对饱和砂土进行大量等q往返球应力p、等p往返偏应力q以及往返p,q三类固结排水动力试验,揭示往返球应力和往返偏应力作用下饱和砂土的应力–应变特性。在继承饱和砂土瞬态动力学理论的基础上,完善由状态边界面、相态转换面及应力历史边界面构成的静动有效全应力空间特性域,建立新的有效应力物态本构模型。由于该模型是建立在球应力–体应变、球应力–偏应变和偏应力–偏应变关系的基础上,因此能够全面反映饱和砂土的应力–应变非线性、硬化性、剪切胀缩性和压密回胀性、应力路径相关性以及球应力–偏应力–变形的耦合性等主要特征。其次,以动力固结理论和瞬态动力学理论为基础,将该本构关系引入到以动力反应–动力固结相耦合、静应力–动应力变化相耦合以及孔隙水压力产生–扩散–消散相耦合,能较全面地反映动力作用下土体应力–应变反应的真实过程为特点的三维瞬态动力方程组,形成饱和砂土体有效应力物态地震反应分析的完整理论体系。更多还原

【Abstract】 Firstly,on the basis of discussion on current analysis methods in soil dynamic responses,the dynamic stress-strain characteristics of sandy soil is revealed by systematical dynamic triaxial tests under fully drained condition with constant spherical stress but cyclic deviator stress,constant deviator stress but cyclic spherical stress as well as cyclic spherical and deviator stresses.These constitutive relationships are further combined with the framework of transient dynamic theory with a total(static and dynamic) effective stress space divided into different zones by critical state line,phase transformation line,and stress space divided into different zones by critical static state,phase transformation line and stress historical line.The constitutive model can be used to consider the sandy soil properties of nonlinearity,hardening,shear dilatation-contraction,compression-swelling,and stress path dependence and coupling of spherical stress with deviator stress.The study is performed upon the relationships of spherical stress-volumetric strains,pherical stress-deviatoric strain,and deviatoric stress-deviatoric strain.In additional,the fundamental of a 3D dynamic consolidation with governing equations based on the basis of transient dynamic theory is introduced with effective stress and dynamic constitutive relationships of physical states.Also,it is established with the coupling of dynamic response with dynamic consolidation,the coupling of static stress and dynamic stress,the coupling of pore water pressure generation,pore water pressure diffusion,and dissipation to simulate true process of stress-strain response of sandy soils and form a complete theoretical framework system of seismic response analysis approach based on effective stress and physical states of sandy soils.更多还原