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.

Analytical and Numerical Study on the Stability of Highway Subgrade with Embedded Loading Berm in Soft Soil Area

“…In addition, from Equations ( 6) and (11), it is known that there are other parameters influencing the subgrade stability, such as ELM density, cohesion, and internal friction. Therefore, it is necessary to further study the influences of these parameters on the stability factors since experimental tests have high requirements for equipment and costs [23] and it is difficult to explore the influences of these parameters on the stability factors using Equations ( 6) and (11). However, numerical simulation is an efficient method to further study the influences of these parameters on the ELB stability factors.…”

Analytical and Numerical Study on the Performance of the Curved Surface of a Circular Tunnel Reinforced with CFRP

“…One end of the spring is connected to the node of the adhesive element, and the other end is connected to the node of the concrete element. The stiffness of each spring is the first-order inverse of the force-displacement relationship curve, which can be calculated as shown in Equations ( 33)-(36) [10,30].…”

“…The successful application of CFRP reinforcement technology in the field of civil building reinforcement has also inspired engineers and technicians to continuously explore the possibility and effectiveness of CFRP reinforcement technology in the field of hydraulic tunnel lining. Since CFRP is characterized by high strength, stable performance, corrosion resistance and light weight [8,9], it can effectively control the continual expansion of lining cracks and prevent the lining from falling off and spalling, which was well applied in the circular hydraulic tunnels of Taohua River Reservoir, Qingshan Reservoir and Dahuofang Reservoir [10]. When the concrete is reinforced with CFRP, the CFRP contributes to the structural strength, mainly by bearing the stress transferred from the reinforced interface.…”