Abstract: In this study, indoorloading tests are performed for triangular lattice, tetragonal lattice, and No.14 Ishaped steel arches to systematically analyze the mechanical properties of steel arches. Then, a steel performance coefficient is introduced to comparatively analyze the comprehensive characteristics of various types of steel arches. The research results reveal the following: (1) In the initial stage of tunnel support, the bonding performance between the lattice arch and shotcrete is better than that of the Ishaped steel arch, and the potential safety risk of the Ishaped steel arch is higher than that of the lattice arch under a concentrated force. (2) Steel arch can be adversely affected by an eccentric load in actual service, especially the tetragonal lattice arch. Therefore, increasing the arrangement of torsional reinforcement at the midspan is recommended.

Key words: tunnel, primarysupport steel arch, concretesteel arch combination, early mechanical properties, steel performance coefficient, comparative test