Micromechanical Damage Model for Rocks and Concretes Under Triaxial Compression
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摘要: 考虑三轴压应力作用下的无限大体深埋椭圆形裂纹的变形场,给出了闭合椭圆形微裂纹的能量释放率.采用能量平衡方法分析了闭合椭圆形微裂纹的扩展条件,得到了代表性体积单元中具有任意空间取向的单个闭合椭圆形微裂纹及其扩展引起的附加柔度张量.分析了闭合椭圆形微裂纹的偏折扩展,得到了微裂纹偏折扩展引起的附加柔度张量.采用Taylor方法考虑微裂纹系统对代表性体积单元变形的影响,引入概率密度函数,得到了三轴压缩下岩石/混凝土的三维细观损伤模型.分析了混凝土的单轴压缩特性,结果表明该模型能够很好地描述实验现象.Abstract: Based on the analysis of the deformation in an infinite isotropic elastic matrix containing an embedded elliptic crack, subject to far field triaxial compressive stress, the energy release rate and a mixed fracture criterion were obtained by using an energy balance approach. The additional compliance tensor induced by a single closed elliptic microcrack in a representative volume element and its in-plane growth was derived. The additional compliance tensor induced by the kinked growth of the elliptic microcrack was also obtained. The effect of the microcracks, randomly distributed both in geometric characteristics and orientations, was analyzed with the Taylor's scheme by introducing an appropriate probability density function. A micromechanical damage model for rocks and concretes under triaxial compression was obtained and experimentally verified.
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Key words:
- elliptic microcrack /
- in-plane growth /
- kinked growth /
- energy release rate /
- micro-macro damage model
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