关键词: 大理岩, 三轴循环加卸载试验, 非线性本构方程, 损伤变量, 岩体耗散能

Abstract: The deformation characteristic, energy dissipation and damage evolution of marble during triaxial compression were studied via triaxial cyclic compression test. The axial strain of marble was separated into elastic strain and plastic strain. The axial elastic strain was in an approximate linear relation with axial stress, while the lateral elastic strain was in an evident nonlinear relation with axial stress. A nonlinear elastic constitutive relation between strain and the stress was proposed based on the assumption of changeable Poisson’s ratio, and on this basis the axial and lateral plastic strains during the whole loading process were identified. The damage variable D of marble was defined in line with the theory of equivalent strain, and accordingly, the damage evolution of marble during triaxial compressive deformation was acquired. The damage evolution was then divided into three stages according to the calculated damage values. Moreover, the elastic strain energy and dissipated energy in each loading-unloading cycle were calculated with finite simulate method. An obvious linear relation was found between the energy dissipation of rock quality unit and the damage increment ΔD, both of which could be used to describe the damage evolution during the whole loading process.

Key words: marble, triaxial cyclic compression, nonlinear elastic constitutive relation, damage variable, energy dissipation