锚索锚固质量检测的应力波法试验研究

Experimental study on stress wave method for detecting anchorage quality of anchor cable

在较长锚索中利用应力波法难以在锚索端头接收到反映锚固体断面变化处的有效应力波信号,以3种特殊形式锚固体(全长注浆型锚固体、存在缺陷段全长注浆型锚固体和存在自由段非全长注浆型锚固体)实际模型为基础,采用锚索端头和底端分别激发应力波信号这2种方式,通过实测应力波振动速度,并与理论分析结果进行对比,验证应力波法检测锚索锚固质量的可靠性。然后,结合锚索端头和底端分别激发应力波信号这2种方式研究锚索端头和底端同时激发应力波信号方式对锚索锚固质量进行检测的可行性。研究结果表明:锚索端头和底端同时激发方式可对锚索锚固质量进行有效检测,且在锚索端头接收到的信号为反映锚固体断面变化处位置中传播路径最短的应力波信号;为了能够区分锚索端头和底端分别激发的应力波信号,建议这2种应力波信号采用不同频率。

The stress wave method is difficult to be applied to obtain effective stress wave signal that reflects the section change of anchorage body in the long anchor cable. Based on the actual models of anchorage body with three special types, i.e. full-length grouting anchorage body, full-length grouting anchorage body with existence of defective segment,and non full-length grouting anchorage body with existence of free segment, and using two stress wave excitation modes,i.e. stress wave signal exciting respectively on top or bottom of anchor cable, the reliability of stress wave method to detect anchorage quality was verified through comparing the theoretical vibration velocity of the stress wave with the measured ones. Then, by combining the above two stress wave excitation modes, the feasibility of stress wave signal exciting simultaneously on top and bottom of anchor cable to detect anchorage quality of anchor cable was studied. The results show that the excitation mode of stress wave signal simultaneously on top and bottom of anchor cable can effectively detect anchorage quality of anchor cable, and signal received on top of anchor cable in this mode is the stress wave signal with the shortest propagation path for reflecting change positions of anchorage body sections. Meanwhile,the two kinds of stress wave signals are suggested to adopt different frequencies to distinguish stress wave signals exciting respectively on top and bottom of anchor cable.