Discrete numerical model for analysis of earth pressure balance tunnel excavation

Two extension projects have been carried out recently on the Madrid Metro, including 97 kin of large-diameter (9.38 m) tunnels. Some technical specifications for the shields (thrust and torque) needed to excavate the tunnels have been analyzed in this work. The soil stability problem at the tunnel face has also been studied. Numerical tools based on a discrete method (particulate materials) have been used for these purposes. Results from the models are compared with real data and show the promising possibilities of the method to design both tunnels and tunneling machines.