Distributed fibre optic sensing (DFOS) provides breakthrough possibilities in the field of structural health monitoring (SHM) in comparison to convention-al spot measurements. It allows the measurements to be registered over entire measuring length, not only in one point of the structure. That is why it is be-coming more and more attractive for geotechnics and civil engineering appli-cations, providing both technical and economic benefits. However, to utilize all advantages of distributed sensing it is necessary to apply appropriate sen-sors, which will be able to accurately reflect the real structural behaviour. The paper discusses in situ application of unique (patented) composite DFOS displacements sensors (3DSensors), which were embedded into the ground layers compacted around the footing. The research was conducted to observe the potential slip plane generated during the pulling the footing out of the ground. Distributed measurements enabled to obtain the vertical displace-ment profiles around the footing within the selected ground layers with a spatial resolution of 1cm. Finally, special visualization of ground defor-mation in 3D space was performed to analyze in detail the cooperation be-tween the footing and the surrounding ground. No other techniques were able to obtain such information, as their presence inside the ground layers would disturb its behaviour. The operational rules of displacement DFOS sensor, way of installation, course of the study as well as the exemplary re-sults are discussed hereafter.