Geomechanical analysis of an underground station of Metro do Porto

This paper presents the Marquês station from Metro do Porto. The station is built in a central elliptical 27m deep shaft, 48 and 40 m wide along its axis, from where two opposite galleries 18 m long and with about 18 m wide form a section of 180 m2. The construction of the station was performed in a heterogeneous granite formation intercepted by a sub-vertical probable fault, slightly oblique to the longer axis on the shaft. Numerical 3D and 2D models were developed, using the formulation of a KBS system in order to determine the geomechanical parameters of the granite formations. The established monitoring plan is also presented and some numerical and monitored results are compared giving with good agreements.