Abstract: In order to establish a support structure design method suitable for mechanized construction of large crosssection tunnels, the calculation equation of the stability coefficient of the tunnel face considering three kinds of advance support measures (advance pipe roofing, face bolting and pregrouting) is deduced based on the limit equilibrium method. Then, the calculation equations of the overall displacement pressure and the local displacement pressure are derived based on the multiple nonlinear regression analysis method, the BQ system and a large number of field test data of displacement pressure of deepcovered tunnels. Later, according to the support structure design method established, the advance support and primary support parameters of tunnels on ZhengzhouWanzhou highspeed railway are presented, and the rationality of the parameters and the practicability of the proposed method are proved by practical application.

Key words: highspeed railway tunnel, large crosssection tunnel, mechanized construction, support structure design, tunnel face stability, deformation pressure