基于双曲正切函数的土动力非线性本构模型

A new nonlinear soil constitutive model based on hyperbolic tangent function

基于双曲正切函数,构造了一种新的土动力非线性本构模型。该模型从双曲正切函数出发,通过平移和缩放构造了土动力应力应变关系的骨架曲线和卸载、反向加载的滞回曲线。相对于其他模型而言,这种新的数学模型参数较少,物理概念明确,形式简单,更利于编程实现,加卸载应力应变关系曲线只需要记忆加卸载转折点处的应力和应变值。将该数学模型应用于场地地震反应分析中,并与常用的等效线性化方法的地震反应结果进行比较,结果初步证明了该本构模型的可行性。

A new nonlinear soil constitutive model based on hyperbolic tangent function is presented,in which the shape of proposed backbone curve is the same as that of the hyperbolic tangent function curve shifted and enlarged by two factors.Such new model is expressed in a simple form and has a straightforward physical meaning.It can be executed by the computer without large computer memory.The only thing needs to be done for obtaining hysteresis loop is the determination of original shear strain and shear stress values at the beginning of unloading and reloading.Efforts have also been made in the seismic ground response analysis with a program developed based on this new stress-strain model.Results comparison with that carried out by the equivalent linear method shows that it is feasible to use this new constitutive model in seismic ground response analysis.Practical significance is of interest to develop such nonlinear soil constitutive model.