基于光纤电流传感的BEAM隧道超前地质预报方法

BEAM tunnel advanced geological prediction method based on optical fiber current sensing

在BEAM综合法的实施中,护盾与刀盘之间较小的接触电阻使得探测电流和屏蔽电流失去隔离,产生泄露电流。实验表明,泄露电流会导致视电阻计算精度的降低,致使隧道超前地质预报产生漏报。为消除泄露电流对超前地质预报造成的不良影响,提出了基于光纤电流传感的BEAM隧道超前地质预报方法,通过在主轴承外缘安装光纤电流传感器,测出分布于主轴承内部的接触电流的大小,消除了它对视电阻测量的影响。实验证实,与BEAM综合法相比,本方法排除了泄露电流的干扰,提高了探测精度。

Low contact resistance between the cutterhead and the shield leads to the loss of insulation between the detecting current and the guarding current in BEAM-INTEGRAL method and generates the leak current.Experiments indicate that the leak current reduces the calculation accuracy of apparent resistivity and causes the omission of geological disasters in advanced prediction.1n order to eliminate negative effects of the leakage current,we propose an advanced geological prediction method based on optical fiber current sensing.This method can measure the leakage current by a fiber current sensor,which is attached on the main bearing of the TBM.The experiment reveals that this method can eliminate the negative influence of the leakage current on the apparent resistance measurement and improve geological advanced prediction’s detecting precision compared with BEAM-INTEGRAL method.