Using tactile pressure sensors to measure dynamic earth pressures around dual-row walls

Abstract

Following the destructive 2011 Tohoku earthquake and tsunami, dual-row retaining walls are being employed in Japan to protect coastal areas from these natural hazards. Dynamic centrifuge tests are conducted to investigate the system behaviour, in particular the earth pressures generated. High-frequency tactile pressure sensors can measure the dynamic earth pressures. By directly measuring the stresses generated during earthquake events invaluable insight can be gained into the dynamic behaviour. However, the processing and interpretation of the raw output can be challenging. This paper describes a processing scheme that can be used to reduce the apparent scatter in the data. This is applied to the earth pressure data collected using the system developed by Tekscan. The calibration and sensitivity correction process is detailed, with attention to the limitations of the assumptions made in the proposed method. The variation of the processed earth pressures with time is considered to better understand the wall behaviour. The distribution along the wall is considered at several instants to gain further insight. To help verify the earth pressure measurements, equilibrium-based methods are used to investigate the consistency between the recorded earth pressures and the outputs from other instruments that directly measure the wall response.