Development of TDR Penetrometer through Theoretical and Laboratory Investigations: 2. Measurement of Soil Electrical Conductivity
Lin, CP
Associate Professor of Civil Engineering and graduate students of Civil Engineering, National Chiao Tung University, Hsinchu, Taiwan

Chung, CC
Associate Professor of Civil Engineering and graduate students of Civil Engineering, National Chiao Tung University, Hsinchu, Taiwan

Tang, SH
Associate Professor of Civil Engineering and graduate students of Civil Engineering, National Chiao Tung University, Hsinchu, Taiwan

(Received 6 January 2006; accepted 30 March 2006)

Abstract

A TDR penetrometer was introduced to allow simultaneous measurements of dielectric permittivity and electrical conductivity during cone penetration. This study focused on the theoretical development and experimental evaluation of electrical conductivity measurement using the TDR penetrometer. Theoretical development takes into account the cable resistance and nonconducting cone shaft, leading to a new data reduction equation and calibration procedure. Measurement sensitivity and spatial sampling bias were experimentally evaluated for various probe configurations. The results show that the measurement sensitivity of interest may be controlled by the geometric factor of the probe. The complication and implications of the spatial weighting bias are discussed. A prototype TDR penetrometer was calibrated and used to perform simulated penetration tests in a soil. Experimental results do not show significant errors in electrical conductivity due to the penetration disturbance, verifying the effectiveness of the TDR penetrometer for electrical conductivity measurement.

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Author Lin CP, Chung CC, Tang SH Title Development of TDR Penetrometer through Theoretical and Laboratory Investigations: 2. Measurement of Soil Electrical Conductivity Symposium , Committee on