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基于临界状态土力学框架,建立了一个剑桥类砂土本构模型,适用于单调静力荷载,加入了剪切硬化、依赖状态的剪胀的概念。屈服面采用倒子弹头型,硬化规律不是采用剑桥模型的体变硬化,而是借鉴Hashiguchi次加载面模型的思想,推导出与Norsand砂模型相同的增量形式的塑性剪应变硬化表达式。流动法则采用加入状态参数概念的修正的Rowe应力剪胀关系,该模型能考虑砂土变形特性对密度和固结压力的双重依赖型,只用一组材料参数就能模拟不同密度和固结压力下的应力应变响应,可反映材料的软化。通过与常规三轴试验、等p路径三轴试验等结果的对比,表明该模型是合理的、有效的。
Based on the framework of soil mechanics in critical state, a constitutive model of sandy soil in Cambridge is established, which is suitable for monotonic static load and adds the concept of shear hardening and dependent dilatancy. The yield surface adopts the reverse bullet type. The hardening law is not the body hardening of the Cambridge model. Instead, the idea of Hashiguchi sub-loading surface model is used to deduce the same incremental plastic shear strain hardening expression as the Norsand sand model. The flow law adopts the modified Rowe stress dilatancy concept which incorporates the concept of state parameters. The model can consider the dual dependence of sand deformation characteristics on density and consolidation pressure, and can simulate different densities and consolidation pressures with only one set of material parameters Under the stress and strain response, can reflect the material softening. By comparing with the results of conventional triaxial test and p-path triaxial test, the results show that the model is reasonable and effective.