砂岩全应力-应变曲线二分段特征的Lyapunov定性分析

提出砂岩全应力.应变曲线的二分法原则,应用混沌动力学Lyapunov评价准则定性研究得到了曲线新的分段特征:试验曲线的所有峰前段均处于混沌状态,证明岩石节理裂隙这一复杂系统的非线性状态演化是客观存在、线性是近似的;节理裂隙系统有85%演化到峰后段时呈有序定常态,表明节理裂隙贯通后的岩石已呈现宏观破坏,线性特征明显:围压作用将延长节理裂隙的贯通过程,使之在峰后呈抵抗性破坏特征;峰后应变长度占总应变长度的2/3及以上时,该阶段节理裂隙系统的状态将主导其演化全过程的状态特征.

Analysing staged features of complete stress-strain curves divided by dichotomy of sandstone qualitatively with Lyapunov theory

Dichotomy for stress-strain curves of sandstone is proposed to study staged features qualitatively with Lyapunov theory of chaotic dynamics. As former parts of all stress-strain curves of jointed sandstones are in chaotic state, the complicated system evolves only in nonlinear state. After ultimate limit, eighty-five percent of joint systems are in orderly state, which states that transfixed jointed sandstone has destroyed in macro state. Term of joints’ transfixion may be longer as the minimum initial stress increases. Then destructive state of sandstone after ultimate strength may be stepped decrease. If strain after ultimate strength is two-third of the complete strain, system state in the stage may dominate whole evolving state of joint system.