基于统一硬化参量的海洋K0固结土动力本构模型

为方便海洋工程中桩土相互作用计算,根据海洋K₀固结土体特性,对现有相关土体本构模型进行简化。在修正剑桥模型的基础上,基于热力学理论,选用耗散功作为硬化参量,结合原状土体的固结属性,推导了适用于黏土与砂土的统一硬化模型。在此基础上,通过采用旋转硬化与等向硬化相结合的硬化理论来表征K₀固结土在循环荷载作用下的硬化规律,同时引入屈服面收缩参数Θ来描述循环荷载加载过程中土体屈服面的演化特性,进而建立了循环荷载下海洋K₀固结土体统一硬化模型。为验证本文提出的本构模型的合理性,开展了2个案例的对比研究,研究结果表明:新提出的统一硬化模型的计算值与实测值吻合,选用的计算参数少且物理意义明确。

Dynamic constitutive model of marine K0 consolidated soil based on unified hardening parameters

In order to facilitate the calculation of pile-soil interaction in marine engineering,the existing soil constitutive model is simplified taking into consideration the characteristics of marine K₀consolidated soil.On the basis of the modified Cam-Clay model and thermodynamics theory,a unified hardening model for clay and sand is derived combined with the consolidation property of undisturbed soil,using the dissipative work as the hardening parameter.Based on the derived model,the hardening law of K₀consolidated soil under cyclic load is achieved by combining rotation hardening with isotropic hardening.And the shrinkage parameterΘof yield surface is introduced to describe the evolution of soil yield surface under cyclic load,and then a unified hardening model of marine K₀consolidated soil under cyclic load is established.A comparative study of two cases is carried out to verify the proposed constitutive model.The results show that the calculated value of the new unified hardening model is in agreement with the measured value,and the new model adopts fewer calculation parameters with clear physical significance.