Stress Transferring Mechanism of a Pressure Tunnel Lining Strengthened with CFRP

Abstract

This paper investigates the stress transferring mechanism of a pressure tunnel strengthened with CFRP. A simplified mechanical model of the internal water pressure transfer from the CFRP to the lining concrete is established, and the key parameters that influence the internal water pressure transfer between the CFRP and lining concrete are identified. A solid-spring-solid three-dimensional finite element model is established. Using the numerical model, the influences of the above key parameters on the ratios of the internal water pressure borne by the concrete and CFRP are investigated. Based on the above results, a reinforcement scheme of the Yellow River Crossing Tunnel is studied and optimized as a case study. This reveals that the elastic modulus and thickness of the CFRP are the two most important factors that affect the ratios of the internal water pressure borne by the concrete and CFRP, and increasing the elastic modulus and thickness of the CFRP can decrease the ratio of the internal water pressure borne by the concrete and improve the stress state of the lining concrete.

Keywords:
Pressure tunnel; CFRP, Stress transferring mechanism; Bearing ratio; Yellow River Crossing Tunnel; Finite element analysis

Graphical Abstract