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采用散粒材料的组构–应力微细观力学分析方法,在颗粒尺度上分析了砂土的原生各向异性强度特性。首先建立了砂土各向异性强度准则,若不考虑初始组构的变化,将蜕化为莫尔–库仑的原生各向异性强度准则,并可直接将现有的经典破坏准则推广到考虑砂土原生各向异性的情况,不需额外模型参数,方便于工程应用。接着基于三轴压缩与伸长试验破坏各向异性发展的不同,建立了考虑中主应力影响的简单破坏应力比–组构关系,建议了考虑组构演化的砂土原生各向异性强度准则,并考虑了砂土密实状态对其各向异性强度的影响。研究结果表明本文建立的原生各向异性强度准则,其物理机理比较明确,考虑了原生各向异性组构的演化,与真三轴试验结果吻合较好,有助于从微细观机理上分析砂土的原生各向异性强度特征。
The structure-stress micromechanics analysis method of the granular material was used to analyze the anisotropy strength characteristics of the sand on the particle scale. First, the anisotropy of sand soil is established. If the initial structure is not considered, it will degenerate into the Mohr-Coulomb anisotropic strength criterion, and the existing classical failure criterion can be directly extended to consider the sand Native anisotropy, without additional model parameters, to facilitate engineering applications. Then, based on the difference of the anisotropy of failure under triaxial compression and elongation tests, a simple failure stress ratio-texture relationship considering the influence of mid-principal stress was established. The strength of anisotropy of anisotropy of sand was considered, The influence of sand density on the anisotropy strength is also considered. The results show that the strength of primary anisotropy established in this paper has a clear physical mechanism and takes into account the evolution of primary anisotropic structure, which is in good agreement with the true triaxial test, which is helpful to analyze the mechanism of sand Strength of native anisotropy of soil.