Abstract: Monitoring the performance of the piled foundations under various loading conditions is generally difficult due to the pile embedment into the ground and usually under the groundwater environment. The paper presents the first application of Brillouin Optical Time Domain Analysis (BOTDA) in the monitoring of the pile displacement performance. Throughout the process of the measured strain along the pile and the boundary condition assumptions, the pile displacement could be obtained from the mathematical model and solutions. The results indicate that, it is feasible to apply the BODTA method in the pile displacement survey. The established mathematical model is appropriate for the deformation interpretation. Further, the strain monitoring using fiber optics is continuous in the time domain and the selected distance increments in the monitoring can meet the mathematical model requirement.

Key words: brillouin optical time domain analysis (BOTDA), anti-landslide caisson, construction monitoring, displacement measurement