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

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. In order to elimi-nate 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 experi-ment 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.