Quantitative modelling of granular soils considering density and pressure effects
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摘要: 亚塑性理论是一个相对较新的本构理论框架，适合于模拟土体等具有强烈非线性特性的颗粒材料。针对Gudehus和Bauer建立的一个亚塑性模型，建议了一个修正模型。原始模型虽能定性地反映粗粒土的剪胀性和应变软化特性随土体初始密实度和应力水平变化的规律，但模型对粗粒土应力–应变关系的定量预测还不能达到令人满意的程度。在Gudehus-Bauer模型基础上，通过在本构方程中增加一个随剪应力水平变化的因子来修正张量函数的结构，增强了模型描述各种应力路径的能力。修正模型还采用了应力变换的方法来改善对粗粒土在三维应力条件下力学响应的模拟质量。论文中给出的数值结果表明，修正后的模型不仅能定性地反映粗粒土的力学响应，还能在很宽广的密实度和应力范围内得到和实验数据相一致的定量预测。Abstract: Hypoplasticity is a relatively new framework for constitutive modelling of granular materials. A revised version of the hypoplastic model for granular soils originally formulated by Gudehus and Bauer is proposed. The original model can qualitatively reproduce the density-dependent behaviour of sand-like granular materials, including shear dilation and strain softening. But it is not good enough for quantitative prediction of stress-strain responses, particularly when the material is very dense. The revision is made by introducing a scalar factor in the tensor-valued function, which enhances the capability of the constitutive equation in capturing various stress paths. A stress-transformation technique is employed in the revised model to improve the predictions of the material response under three-dimensional stress condition. Numerical results are presented with the experimental data to demonstrate the better performance of the revised model.
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Keywords:
- granular soils /
- density /
- stress level /
- quantitative modeling /
- hypoplasticity
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