锚杆锚固质量的多尺度熵评价方法研究

Study on Multiscale Entropy Evaluation Method of Bolt Anchorage Quality

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。

We set up finite element model of anchorage system to study anchorage quality detection of anchorage system by stress wave method and studied propagation properties of stress wave in the case of the increasement of defect length of anchorage system. We calculated multiscale entropy（ MSE） of reflected signals and found that the MSE of reflected signals obtained from defective anchorage system are larger than the defectless one on most time scales,that means the complexity of reflected signals obtained from defective anchorage system is higher. A parameter named pseudo R square（ PR2） was defined to describe the deviation degree of two MSE curves of the reflected signals obtained from defective and defectless anchorage system quantitatively. By computing,we found that the longer the axial length of defect is,the smaller the value of PR2is; the larger the deviation degree of the two MSE curves is,and the higher the complexity of reflected signals obtained from defective anchorage system is. This shows that the anchorage quality can be evaluated effectively by MSE method.