Analysis of Reliability Degree for Primary Support System in Tunnel

Structure performance function is established with the consideration of safety factor, taking the primary support structure as a series system and determining the invalidation model of the system, and then the internal forces of primary support are expressed by the limit displacement. The calculating analysis also takes material parameters and geometrical dimension into consideration. Based on a typical tunnel, the reliability degree of the whole system is calculated, which indicates that the reliability degree is rather smaller at a certain section of the primary support, but it can satisfy design requires of the whole system, and the tunnel stays in a safety state.