【摘要】 从应力–应变滞后回线"X"形的切线模量出发,探讨岩石滞后的定量描述。高应力作用下岩石的应力–应变滞后回线的形状是尖叶状的,反映在正弦波应力作用下应变的相位在加、卸载反转点处发生改变;滞后回线的切线模量和泊松比呈不对称的"X"形,且在加、卸载反转点处是不连续的。这种岩石在应力–应变图中出现的滞后回线是由于循环荷载时应力和应变的相位不同步造成的。理论计算和实验结果表明,岩石应力–应变滞后回线切线模量"X"形切线模量的夹角θ′与岩石的耗散角有确定性关系,θ′同样也反映岩石的滞后程度,它与岩石的耗散角在衡量岩石的滞后方面具有同等价值。更多还原

【Abstract】 Hysteresis loop of rock subjected to cyclic loading is the phenomenon of nonclassical nonlinearity. The purpose of this paper is to discuss the quantitative expression of hysteretic behaviors in rocks by introducing a measurement of X-shaped tangent modulus of stress-strain hysteresis loop. The stress-strain hysteresis loop is cusped,which is the consequence of phase change of strain at the reverse point of loading and unloading under the applied external sinusoidal force. Tangent modulus and tangent Poisson′s ratio are in asymmetrical X-shaped as the function of axial strain under cyclic loading,and they both are discontinuous at the reverse point of loading and unloading. Hysteresis observed in rock′s stress-strain diagram under cyclic loading condition is the consequence of phase difference between the stress and its correspondent strain. Theoretical calculation,based on the above observed fact and a series of uniaxial stress cycling measurements for sandstone and marble,demonstrates the deterministic relationship between inclination of X-shaped tangent modulus of hysteresis loopθ′ and its dissipation angle. Inclination of X-shaped tangent modulus of hysteresis loop θ ′ can be used to reflect nonlinear stress-strain hysteretic degree in rock and rock-like materials.更多还原