A Nonlinear Lateral Stress-Strain Model of Intact Loess in Plane Strain Unloading Conditions
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摘要: 黄土在我国分布广泛,在工程实际中会遇见基坑、边坡开挖、挡土墙等平面应变卸载类工程问题。通过平面应变改造后的真三轴仪,模拟平面应变条件下的侧向卸载应力路径研究,开展原状黄土的平面应变卸载剪切试验,揭示平面应变侧向卸载应力路径下原状黄土的侧向应力-应变的非线性演化规律,进而提出一种复合指数函数来描述原状黄土的侧向卸载应力-应变关系,并给出了模型参数的求解方法。该模型反映含水率和固结围压变化对侧向应力-应变关系的影响,参数求解简单,计算结果与试验数据吻合度较高,可为卸载类黄土工程的侧向变形预测提供参考。Abstract: Loess is widely distributed in China. In engineering practice, plane strain unloading engineering problems such as foundation excavation, slope excavation and retaining wall will be encountered. Through the true triaxial apparatus of Xi 'an University of Technology modified by plane strain, the study of the lateral unloading stress path in plane strain condition was simulated, and the plane strain unloading shear test of intact loess was carried out. The nonlinear evolution law of lateral stress-strain of intact loess under the lateral unloading stress path of plane strain was revealed, and a composite exponential function was proposed to describe the lateral unloading stress-strain relations of intact loess, and the solution method of model parameters was obtained. The model reflected the influence of moisture content and confining pressure on the lateral stress-strain relations. The parameter solution was simple, and the calculation results were in good agreement with the experimental data, which showed the rationality and accuracy of the established composite exponential model. It can provide a reference for the lateral deformation prediction of unloading loess engineering.
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Key words:
- plane strain /
- intact loess /
- new model of composite indexes /
- lateral unloading
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