The System Research And Simulation On Geological Exploration In Tunnel Drivage

This paper researches on method of geological exploration in tunnel drivage. In the exploration process of tunnel engineering and underground engineering, the front may encounter unpredictable geological conditions which cause great inconvenience to the normal construction of the tunnel. However, the system research and simulation on geological exploration in tunnel drivage can provide an effective probe means for geological conditions. It provides real-time accurate data for the construction to avoid accidents and ensures the successful completion of the project.At present, most of us use the direct current resistivity in China in terms of geological exploration. Difficult work of the current polarization in the electrical method is not easy to guarantee stabilities to the voltage between measuring electrodes and natural potential differences. This paper adopts AC IP method, which can overcome this shortcoming and obtain accurate results; it uses pole-pole device system to study and simulate about geological exploration in tunnel drivage. Pole-pole device system is mainly composed of the transmitter module, measurement data and the host computer processing module. Its features are that measuring electrodes are rare and measuring method is easy. Besides, protection current in the outer ring can make the spread of current deeper.This paper firstly selects three-dimensional harmonic analysis function of ANSYS finite element simulation software. Secondly, it mainly does geological exploration simulates on high and low resistivity abnormal body with protection current and without protection current. The simulation voltage and current values calculate resistivity whose change can explore geological anomalies, and the simulation results of AC IP method can explore forward geological type. Subject research is to build the sandbox model of special geological conditions, and according to pole-pole device system construction completes simulated experimental measurement. The experiment adopts low-frequency AC excitation current. Then respectively measure experimental data which is measured on high and low resistivity abnormal body with protection current and without protection current. The experimental data is passed to the host computer by data acquisition card. In the host computer, using LAB VIEW completes signal low-pass filtering and data sampling. Finally, MATLAB processes data to come to a conclusion that measured resistivity is abnormal.Comparing experimental data to ANSYS simulation results, it can conclude that both results are consistent. Therefore, exploration methods and devices which the paper adopts can effectively explore geological abnormal condition in front of tunnel drivage.