Novel Single-Point-Type Tactile Pressure Sensors for Earth and Soil-Structure Interface Contact Pressures Measurement

ABSTRACT The single-point-type tactile pressure sensor (TPS) is a thin and flexible piezoresistive sensor that shows promise in overcoming the limitations of current methodologies for measuring earth pressure within soils and contact pressure at soil-structure interfaces. Despite this potential, the feasibility of the TPS application has not been verified in physical model tests of soil-structure interaction. This article addresses this gap by introducing a new earth pressure cell (TPS-EPC) with limited thickness and a soil-structure interface contact pressure transducer (TPS-ICPT) conforming to curved interfaces based on a single-point-type TPS. The article presents a comprehensive methodology encompassing sensor design, signal processing, and calibration. Additionally, a nonlinear signal conversion method is recommended to enhance measurement accuracy. Compared with traditional EPCs, TPS-EPCs with the suggested methodology offer more precise earth pressure measurements due to reduced arching effects resulting from their limited thickness. The feasibility of new sensors was validated for the first time in the physical modeling of cyclic axial soil pipe interaction, providing a new and highly sensitive method for soil pressure measurement and yielding valuable insights into soil-pipe interaction behavior, including constrained dilation on the soil-pipe interface and the evolution of soil arching on the pipe.