Study on structural analysis technique of loess tunnel based on multi-index evaluation

Abstract The geological environment of loess tunnel is very complicated in the process of construction and operation, and the actual supporting parameters and surrounding rock pressure of loess tunnel have great uncertainties, which increases the difficulty of performance evaluation. In this paper, a distributed optical fiber monitoring system for loess tunnel is established by means of field investigation, theoretical analysis and field monitoring, which can monitor the tunnel displacement rate, the initial steel arch stress, the axial force of the anchor bolt, the lining stress and the width of the lining crack. Based on the theory of extension, the long-term performance evaluation model of loess tunnel is established, which comprehensively and objectively considers the influence of various influencing factors on the long-term performance of the tunnel, makes a quantitative judgment on the long-term performance of the typical section of loess tunnel, and provides a theoretical basis for the next tunnel maintenance plan, which is of great significance for the improvement of the maintenance technology of loess tunnel.