Prediction of tunnel-induced settlements in soft ground

Tunneling in soft ground always leads to stress redistribution and displacements in the surrounding soil. Therefore, when planning shallow tunnels in areas sensitive to settlements, the prediction of the deformations above the tunnel is very important. In order to describe tunnel-induced settlement troughs, the Gaussian distribution function is most commonly used. Its input parameters are the point of inflection i and the volume of the settlement trough, described by the so called volume loss VLs. These two parameters have to be defined in order to be able to predict a settlement trough which is close to that in situ. In the literature, the results of settlement measurements are frequently presented, however the results are mostly not comparable due to different boundary conditions. Therefore, the range of published settlement troughs vary widely and there are very few as well as inaccurate datainformation concerning the size of the parameters i und VLs. In this paper the empirical prediction-method of Fillibeck is introduced to determine the parameters i und VLs which was deduced from more than 350 carefully selected and proved measurement results as well as accompanying 2D- and 3D- FE-calculations using advanced constitutive models.