摘要
近几年在野外和实验室都发现高孔隙岩石中局部化变形的压缩带、剪切带和膨胀带,是目前岩石力学、岩石物理和本构模型研究的热点之一。基于局部变形带在水利、石油、核废料处置、垃圾处理、环境污染的治理和地质构造、工程地质和岩土工程中的实际意义,介绍以局部化分岔理论为基础的多孔岩石的压缩带、剪切带的理论、形成条件和判别条件,以及与压缩带、剪切带和膨胀带相应的临界硬化模量。基于帽子模型,介绍椭圆形屈服帽上的压缩和剪切带,以及它们与σ-ε曲线之间的密切关系。在低围压下的σ-ε曲线上的第一个零模量点也就是应力平台对应于压缩带,即为帽子模型的体积屈服面;继续加载使σ-ε曲线继续上升到标本产生硬化,直到σ-ε曲线上出现第二个零模量点,也就是σ-ε曲线的峰值对应于剪切破坏,此时应力状态处于帽子模型的剪切屈服面上。同时还给出大量不同颗粒尺寸、不同孔隙度砂岩轴对称压缩试验结果,它们也可用1/4椭圆帽子模型来描述。
Recently, localized planar zones of deformation have been discovered in high-porosity rock, which are called compaction bands, shear bands and dilation bands. It is one of the most concerned issues in the research of rock physical and constitutive relations. The research of localized deformations has practical significance in the storage of water, oil, nuclear wastes, the disposal of garbage and environmental pollution. It is also helpful for the research of geological structure, engineering geology, and engineering of soils and rocks. The compaction band and shear band theories, based on localized bifurcation, are introduced. The conditions for band formation and discrimination in porous rocks and the critical hardening modulus for compaction bands, shear bands and dilation bands are also introduced. The compaction bands and shear bands on an elliptic yield cap are introduced based on the cap model. They are close related to the σ-ε curves. Under low confining pressure, the first zero modulus point, i.e. the shelf, corresponds to the compaction band, or the volumetric yield surface of cap model. When loading continues, the σ-ε curve keeps ascending until the sample hardens. The second zero modulus point in the σ-ε curve, i.e. the peak of the σ-ε curve, corresponds to the shear failure, or the shear yield surface of the cap model. Mass experimental results obtained from axisymmetric compression tests on sandstones with different grain scales and porosities can be described by the same cap model.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第A02期3888-3898,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(40474065
40874093)
关键词
岩石力学
压缩带
剪切带
膨胀带
帽子模型
分岔理论
rock mechanics
compaction band
shear band
dilation band
cap model
bifurcation theory
