Geophysical Journal | 2009 volume 31 4

Capacitance sounding method - untapped reserve of stationary geoelectrics

© Yu. A. Dashevsky

Untapped reserves of DC geophysical methods were revealed. A capacitance sounding method has been proposed and developed for evaluation in a real-time on a continuous basis the actual thickness and dielectric permittivity of asphalt pavement. The patented method is based on the measurement of the electrical capacitance between two electrodes. The first one is grounded into the soil immediately adjacent to the side of the road. The second (sensing) electrode is mounted on a motor-driven positioner to obtain the capacitance measurements at multiple locations along the direction perpendicular to asphalt surface. A distinguished feature of the proposed technology is that the measured signal depends only on the thickness and the dielectric permeability of the asphalt layer. All underlying layers do not affect the capacitance readings in any way. A set of capacitance values versus the electrode position is considered as a sounding curve. Software tools were created for solving forward and inverse problems of the capacitance sounding. An unknown thickness and permeability are derived from a real-time 2D inversion of the data obtained.

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