Mechanized tunneling in difficult geological conditions, such as soils with significant swelling potential due to water uptake by the clay minerals, depends not only on the calibration of the tunnel boring machine to the ground characteristics, but also on the ability of the tunnel lining to tolerate localized swelling pressures. In order to avoid the risk of damage to the tunnel lining, additional radial layers such as a compressible tunnel lining segment and a compressible annular gap grout can be included. However, the deformability of a tunnel support after reaching a certain yielding load affects the distribution of the stresses and deformations around the tunnel and as a consequence determines the magnitude and buildup of the swelling pressure. Thus, the goal is to develop a lining system i.e. material design and structural design that ensures an optimal soil-structure interaction through a synergy of computational and experimental techniques.
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