Hydraulic-mechanical interaction of pervious concrete lining considering lining cracking in pressure tunnels

Concrete lining plays key role in high-pressure water diversion tunnels, where accurately predicting their cracking and leakage behavior is essential for effective engineering design. However, due to the complexity of the working environment and load conditions, the influencing patterns of lining cracking and leakage remains not fully comprehensive and the design methods need improvement. This paper aims to contribute to deepen the understanding of hydraulic-mechanical interaction of pervious concrete lining in pressure tunnels. It conceptualizes the tunnel as a structure comprising concrete lining, grouting ring, and surrounding rock. An analytical model is developed based on principles of displacement continuity and flow continuity, considering both internal and external water pressures. By comparing with existing analytical solution, physical model experiment, and engineering monitoring data, the correctness of the established model was verified. This model comprehensively considers internal and external water boundary conditions for both the lining-surrounding rock structure and the lining-grouting ring-surrounding rock structure, thereby broadening its applicable scenarios. Using the control variable method, the study analyzes the influence of factors such as concrete grade, reinforcement ratio, lining thickness, elastic modulus of surrounding rock, permeability coefficient of surrounding rock, grouting ring thickness and permeability coefficient of grouting ring on lining cracking and leakage, using indicators like steel stress, crack width, and leakage. Finally, the study proposes an optimization design methodology for pervious concrete lining, supported by illustrative examples that demonstrate its applicability in engineering practice. This research contributes valuable insights into enhancing the reliability and performance of concrete lining in high-pressure tunnels.