Using a Parallel Helical Sensing Cable for the Distributed Measurement of Ground Deformation

Area of Science:

• Geotechnical Engineering
• Geophysical Measurement
• Sensor Technology

Background:

• Accurate measurement of surface and underground deformation is critical for geological disaster monitoring.
• Existing methods may lack the distributed sensing capabilities required for comprehensive ground monitoring.

Purpose of the Study:

• To propose and validate a parallel helical sensing cable (PHSC) for monitoring large ground stretched deformation.
• To establish the relationship between PHSC characteristic impedance and deformation for distributed measurement.

Main Methods:

• Development and structural analysis of the parallel helical sensing cable (PHSC).
• Derivation of distributed capacitance, inductance, and characteristic impedance based on a stretched-structure model.
• Application of time-domain reflectometry (TDR) to analyze the characteristic impedance and deformation relationship.
• Laboratory calibration using a tensile test platform to validate the measurement accuracy.

Main Results:

• A clear functional relationship was established between stretched deformation and PHSC characteristic impedance.
• Laboratory tests demonstrated high accuracy, with multi-point positioning errors < 0.01 m and deformation errors < 3 mm.
• Experimental results closely matched theoretical calculations, confirming the model's validity.

Conclusions:

• The parallel helical sensing cable (PHSC) is a suitable technology for distributed ground stretched deformation measurement.
• The TDR technique combined with PHSC provides a reliable and accurate method for geological monitoring applications.