隧道锚杆锚固质量无损检测误差控制技术研究

Research on the Error Control Technology of Bolt Anchorage Quality Nondestructive Detecting of Railway Tunnel

研究目的:隧道锚杆施工具有隐蔽性强和不易检测的特点,以往采用拉拔试验的检测方法对隧道结构支护体系具有破坏性且不适用于大批量检测,因此有必要采用无损检测技术对锚杆的锚固质量进行检测。而现有的无损检测技术精度受多种因素影响,导致检测精度参差不齐,影响检测结果。为了在不破坏既有支护体系的前提下批量检测锚杆锚固质量,有必要对锚杆无损检测误差控制技术进行研究。研究结论:(1)激振信号质量、振动信号提取能力以及计算波速精度对锚杆锚固质量无损检测精度有重要影响;(2)通过控制激振频率、力度以及激振方位,可有效提高激振信号质量;(3)改良传感器与锚杆的连接方式以及灵活选取传感器位置对增强振动信号的拾取能力有明显作用;(4)鉴于标定法确定计算波速的缺点,提出了预设法确定计算波速,通过综合采用标定法和预设法可有效提高计算波速精度;(5)本研究成果可为隧道锚杆锚固质量无损检测技术的改进提供思路和方法。

Research purposes： In view of the strong concealment and the difficulty for detecting of tunnel bolt construction,it＇ s necessary to use the nondestructive detecting technology to test the anchorage quality of the bolt because the pull-out test is destructive to the tunnel support system. However,the precision of existing nondestructive detecting technology is affected by many factors which lead to the uneven detection precision and finally affect the detection results. In order to test the anchorage quality without destroying the support system,it＇s necessary to study the error control technology of bolt anchorage quality.Research conclusions：(1） The quality of excitation signal,the extraction capability for reflected signal and the accuracy of the calculated wave velocity have important influence on the detection precision of bolt anchorage quality;(2） The quality of excitation signal can be improved significantly by controlling the excitation frequency,excitation intensity and direction;(3） Improving the connection mode between the sensor and the anchor and selecting the position of the sensorflexibly can enhance the extraction capability of reflected signal effectively;(4） In view of the shortcomings of the calibration method for determining the calculated velocity,the presupposition method is proposed in the paper,and the accuracy of calculated velocity can be improved by combining these two methods;(5） The research results will provide ideas and methods for the improving of the nondestructive detecting technology of bolt anchorage quality.