大理岩细观裂纹动态演化特征研究

通过对大理岩试样应变响应和表面裂纹图象的实时观察,以及试样表面细观裂纹萌生、扩展图象的研究和相应宏观试验的量化研究,基于细观力学与热力学的基本理论,采用均匀化的基本方法,主要研究大理岩在单轴压缩条件下的损伤演化特征。提出弹性假设,岩石被认为是由岩石基质和裂纹组成,且二者符合叠加原理,并将裂纹分为张开裂纹和闭合裂纹2种,并从细观力学角度和热力学角度进行分析,假设在岩石受力的初始阶段裂纹主要受张拉力作用,随着裂纹闭合,剪压作用逐渐对岩石的损伤破坏起控制作用。得出了裂纹损伤演化的理论规律特征、压剪条件下考虑非弹性的库仑摩尔准则的运用及裂纹的法向位移与切向滑移之间的相互关系,进一步探讨了单轴压缩条件下损伤动态演化的特征。

Studies on Meso-crack Dynamic Evolution Properties of Marble

Through observing the strain response and the surface crack image of marble samples, researches on surface micro crack initiation of samples, the image expansion and the corresponding experimental quantitative were made. Based on the fundamental theories of micromechanics and thermodynamics, and with the help of fundamental method of homogeneous, the damage evolution properties of marble under uniaxial compression were mainly investigated. The elasticity assumptions were put forward, and rock host and crack was recognized as the composition of rocks, both of which conform to the principle of superposition. The cracks were divided into open crack and close crack and were analyzed form the perspective of micromechanics and thermodynamics. On the hypothesis that the crack was under tensioning force at initial time, shearing pressure become the main force to the rock damage when crack closed. The rule of crack evolution properties was determined, and the relationship between crack normal motion and tangential motion was represented with application of non-elasticity Mohr-Coulomb criterion under shearing pressure. Lastly the characteristics of the damage dynamic evolution were discussed further under uniaxial compression.