Measurement of earth pressures on curved surface of thin film pressure sensor

Measuring the earth pressure with rigid soil pressure cell (SPC) is a common test method in geotechnical tests. However, the traditional rigid soil pressure cell is not suitable for measuring the earth pressures on curved surface such as piles or buried pipelines because of its limitations such as diaphragm subsidence, "embedding" effect, incomplete fitting of measuring surface and large buried space. The measurement circuit and calibration devices are designed for the characteristics of the thin film pressure sensor. The calibration characteristics are analyzed, and the influences of deflection on the measurement of the film pressure sensor are preliminarily investigated. Finally, the capabilities of the traditional rigid soil pressure cell and the thin film pressure sensor to measure the soil pressures on curved surface are compared and analyzed through experiments. The results show that the thin film pressure sensor can effectively avoid the "embedding" effect, reduce the measurement error, and is easy to install.