中文摘要：

为了更好的反映基坑开挖后土体的变形非线性特性,采用幂函数描述土体剪切过程中切线模量随主应力差值增大而衰减的过程。积分得到主应力差值和应变的数学表达式,其反映的数学规律符合一般土力学模型的要求。对应于不同的幂指数,该表达式可以很好拟合三轴试验应力-应变曲线。基于Duncan-Chang模型参数确定的方法,提出了本文模型参数的确定方法。在通用有限元软件基础上二次开发了模型的计算程序。应用于某基坑变形的计算结果表明,本文提出的模型比Duncan-Chang模型能更好的预测围护结构的变形。

英文摘要：

To reflect well the nonlinear deformation character of soil during excavation,power function was employed to describe the process of tangent modulus decay with the principal stress difference decreasing during the shearing process of soil.The mathematical expressions between principal stress difference and strain were attained by integration,which was consistent with the requirement of general soil model.The expressions with different power exponents could fit stress-strain curves of triaxial test.Based on the method defining by parameters of Duncan-Chang model,the parameters of model were put forward.On the platform of a general finite element software the computing programs for the model were redeveloped,which was employed to precast deep excavation deformation.The results show the model proposed can predict better the enclosure deformation than Duncan-Chang model.