ABSTRACT

Settlement parameters used in empirical estimations and notations are presented in Figure 5. Assumptions used in the estimations are as follows:

• Cross-section of the tunnel is circular. • Tunnel is shallow. • Tunnel passes through clay formation. • Tunnelling method is NATM. • Estimations are valid for completed primary sup-

port (wire mesh shotcrete bolts lattice). • Since the excavation of other tunnel next to 35 m is

completed, the settlement interaction between the tunnels is ignored.