Performance of a Diaphragm-Type Boundary Pressure Transducer Under Cyclic Loading

摘要

Investigation of soil-structure interaction involves understanding of the complicated rheology and functioning of the pressure sensing devices. As earth pressure cell (EPC) output is used to interpret the stress in the soil at the point of installation of cell, experiments involving careful calibration of the pressure cells are very crucial. In view of the importance of in-soil calibration, the present study is focused on developing a relationship between the applied stress and the measured output, when the soil is subjected to cyclic loading. The effect of soil type and its thickness on pressure cell output under cyclic loading is studied using two types of soils: sand and kaolin, and soil layer thickness in the range of 0.25 D_(EPC) to 2.5 D_(EPC), where D_(EPC) is the diameter of the EPC. In-soil calibration under the application of cyclic loading demonstrated substantial hysteresis and reduction in the EPC sensitivity. Increase in residual stresses is observed to increase with soil thickness after the first cycle. It is also observed that the critical thickness for a given EPC is not a unique value, but varies with soil type.