关键词: 岩石力学, 晶粒尺度, 强度, 杨氏模量, 破坏角, 内摩擦

Abstract: The texture of mineral particle is the key point to the mechanical property of rocks. Two kinds of marbles are uniaxial and triaxial compressed. One is slightly weathered with fine-crystal in size of 0.5mm～1mm, the other is weathered with silt-crystal in size of 0.2mm～0.5mm. The silt-crystal marble has much internal boundary to slip during compressing, so the Young’s modulus willbe changed greatly with the cohesion, and the dispersion of Young’s modulus is greater than that of strength. On the other hand, the fine-particle marble is 3 times in Young’s modulus but only 20% in uniaxial strength more than the silt-particle marble. In pseudo-triaxial compression, the Young’s modulus increases with confining pressure for silt-crystal marble, but it is nearly the same as fine-crystal marble. The triaxial strengths of the two marbles in ductile deformation are closed each other. The angle of shear failure increases with the confining pressure and finally reaches the value from Coulomb criterion The supporting capacity of marble specimen is only related to the confining pressure and no matter with the loading path, material strength and flaws. The internal friction between crystals determines the strength and deformation of marble.

Key words: rock mechanics, crystal size, triaxial strength, Young’s modulus, crack angle, internal friction