压缩荷载条件下大理岩细观损伤动态理论分析

Dynamic theories of meso-damage evolution of marble under uniaxial compression conditions

基于细观力学与热力学基本理论,采用均匀化方法,研究大理岩在单轴压缩条件下的损伤演化规律.首先,认为岩石由岩石基质和裂纹组成,并且岩石基质和裂纹二者符合叠加原理;其次,将裂纹分为张开裂纹和闭合裂纹2种,从细观力学角度和热力学角度进行分析,分析时假设岩石受力初始阶段裂纹主要受张拉力作用,随着裂纹的闭合,剪压作用逐渐对岩石的损伤破坏起控制作用;最后,根据分析结果建立了描述裂纹损伤演化规律的表达式,并通过SEM细观实验验证了理论分析结果.

Based on the fundamental theories of the micromechanics and the thermodynamics,the damage evolution rules of marble under the uniaxial compression conditions were studied by use of homogeneous methods. Firstly,the marble was regarded as the composition of rock matrixes and cracks,and the two parts conformed to the superposition principle. Secondly,the cracks were divided into the open and close cracks. The relevant analysis was performed from the perspectives of the micromechanics and the thermodynamics under the hypothesis that the cracks were acted by tensile forces at the initial stage and the damage of the marble was gradually dominated by shear compression with the closing of the cracks. Finally,an expression for the damage evolution rules of the marble was established according to the analytic results. The theoretical results were validated by SEM meso-scale experiments.