Fabrication and performance evaluation of a novel FBG-based effective stress cell for directly measuring effective stress in saturated soils

Generally, effective stresses of saturated soils are determined by subtracting the measured pore-water pressure from the total earth pressure. In this paper, a novel FBG-based effective stress cell (FBG-ESC) for directly measuring effective stress in saturated soils is fabricated. Because of the counteraction of pore-water pressures acting on the front and back surface, the deflection of sensing plate is induced by the average pressure of soil particles only and thus the effective stress is directly measured. The good performance of FBG-ESC in saturated CDG soil under a multi-stage loading has been validated by comparison with the calculated results. Moreover, the FBG-ESC has been applied in a physical model to monitor the evolution of effective stress in saturated clayey soil subjected to complex loadings. The results demonstrate that the FBG-ESC can be also utilized in marine environment.