摘要
高温冻土本构模型是准确计算冻土体应力与变形的关键.基于修正剑桥模型及双屈服面理论,考虑高温冻土黏聚力及内摩擦角的影响,以整体变形εv-lnp曲线描述试样变形特征,采用应力路径相关因子修正当前屈服面及参考屈服面硬化参量,建立了一个高温冻土双屈服面统一本构模型.结合弹塑性理论推导获得了应力应变关系的增量形式,给出了模型参数的含义与简便确定方法,定义了反映高温冻土当前状态的固结参数及潜在强度,剖析了其与硬化参量之间的相互依赖、相互制约动态循环关系,分析了整个应力路径中的模型状态演化过程,利用试验数据对构建的本构模型进行了验证,结果表明提出的本构模型能够很好地预测高温冻土在常规三轴应力路径下的应力应变行为.
Abstract
The constitutive model for warm frozen soil is crucial for accurately calculating the stress and deformation of frozen soil layers.Based on the modified Cambridge model and the dual-yield surface theory,taking into account the influences of cohesion and internal friction angle of warm frozen soil,the deformation characteristics of the specimens are described by the overall deformation curve εv-lnp.The hardening parameters of the current yield surface and reference yield surface are modified by stress path correlation factors.A unified constitutive model of dual-yield surface for warm frozen soil is proposed.The incremental form of the stress-strain relationship is obtained based on the elastic-plastic theory.A convenient method for determining the model parameters is provided.The consolidation parameters and potential strength parameters that reflect the current state of warm frozen soil are defined.An analysis of the dynamic cyclic relationship and interdependence between these parameters and hardening parameters is presented.The experimental data are used to validate the constructed constitutive model,and the results show that the proposed model can accurately predict the stress-strain behavior of warm frozen soil under conventional triaxial stress conditions.
维普
万方数据