A Semi-Automatic Coupling Geophone for Tunnel Seismic Detection

Area of Science:

• Geophysics
• Civil Engineering
• Seismology

Background:

• Conventional geophones used in tunnel seismic methods exhibit limitations including narrow spectral width, low sensitivity, and poor coupling with tunnel walls.
• These limitations hinder accurate geological detection ahead of the tunnel face, impacting construction safety.

Purpose of the Study:

• To develop and evaluate a novel semi-automatic coupling geophone designed to overcome the limitations of conventional geophones.
• To improve the efficiency and accuracy of seismic data acquisition for tunnel construction safety.

Main Methods:

• A semi-automatic coupling geophone was designed, incorporating a piezoelectric sensor with a 10-5000 Hz spectral range and 2.8 V/g sensitivity.
• The geophone automatically couples to the tunnel wall via internal springs after manual insertion into a borehole.
• Comparative experiments were conducted against conventional geophones, and seismic data were processed using forward modeling.

Main Results:

• The semi-automatic coupling geophone demonstrated a significantly higher data spectrum compared to conventional geophones.
• Seismic imaging results using data from the new geophone more accurately reflected actual geological conditions.
• Installation time and cost were reduced with the semi-automatic coupling geophone.

Conclusions:

• The semi-automatic coupling geophone efficiently acquires high-fidelity seismic data, enhancing geological detection for tunnel construction.
• This technology offers a valuable improvement for ensuring tunnel construction safety through better subsurface imaging.