论文部分内容阅读
建立了基于应力波法检测锚杆锚固质量的有限元分析模型,研究了锚固系统缺陷轴向长度增加情况下应力波的传播特性。计算了反射信号的多尺度熵,发现有缺陷锚固系统反射信号的多尺度熵在大部分时间尺度上比无缺陷的大,即有缺陷锚固系统反射信号的复杂度高。引入伪判定系数参量定量描述有缺陷和无缺陷时反射信号多尺度熵值曲线之间的偏离程度,计算发现缺陷的轴向长度越长,伪判定系数越小,说明2条多尺度熵值曲线的偏离程度越大,即该缺陷长度对应信号的复杂度越高。结果表明利用多尺度熵方法可对锚杆锚固质量进行有效的评价。
A finite element analysis model based on stress wave method to detect the bolt anchorage quality was established. The propagation characteristics of the stress wave under the condition of the axial length of the anchoring system was increased. The multi-scale entropy of the reflected signal is calculated. It is found that the multi-scale entropy of the reflected signal of the faulty anchoring system is larger than the non-defect on most time scales, that is, the complexity of the reflected signal of the faulty anchoring system is high. The parameter of pseudo-decision coefficient was introduced to quantitatively describe the degree of deviation between multiscale entropy curves of the reflected signal with or without defects. The longer the axial length of the defect is, the smaller the pseudo decision coefficient is, indicating that two multiscale entropy curves The larger the degree of deviation, that is, the higher the complexity of the signal corresponding to the defect length. The results show that the multi-scale entropy method can effectively evaluate the anchoring quality of rock bolts.