基于表面位移的岩石失稳前兆识别研究

Study on precursor identification of rock instability based on surface displacement

预测岩石破坏或失稳是岩石力学研究的重要内容,采用非均质岩石破裂的数值模拟和岩石单轴压缩的物理试验,研究岩石单轴加载过程中试件表面测点的位移变化规律,提出岩石表面多测点的位移增量拟变异系数计算公式,分析位移增量拟变异系数与应力曲线的对应关系。研究结果表明:多测点的平均位移增量拟变异系数与岩石失稳紧密相关。在线弹性阶段及非线性塑性阶段,位移增量的拟变异系数变化平稳,趋于定值:在岩石失稳时,刻,位移增量的变异系数骤增。因此,能够利用位移增量的拟变异系数变化趋势预测岩石发生失稳的时刻,或者预判岩石达到应力峰值程度。

It is important to accurately predict rock failure or instability in rock mechanics.In this paper,we study the displacement variation law of measuring points on rock surface during the process of uniaxial loading by the numerical simulation and experiment of rock uniaxial compression.Through the calculation formula of displacement increment quasi-variation coefficient of multi-measuring points on rock surface proposed in this paper,the corresponding relationship between displacement increment quasi-variation coefficient and stress curve is analyzed.The results shows that quasi-variation coefficient of mean displacement increment of multiple measuring points on rock surface is closely related to rock instability.In linear elastic and nonlinear plastic stage,the quasi-variation coefficient of displacement increment changes smoothly and tends to be constant.However,before rock instability,the quasi-variation coefficient of displacement increment of corresponding rock multi-measuring points will increase sharply.Therefore,the variation trend of quasi-variation coefficient of displacement increment can be used to predict the time of rock instability,or predict the degree of rock reaching the peak stress.