Adaptive lining technology for hydraulic tunnels in complex operating environments

In response to the complex operational environments encountered in tunnel engineering， such as alternating high internal and external water pressures， large deformation， fault dislocation deformations and high geothermal temperatures， adaptive lining technology tailored to varying conditions was developed for hydraulic tunnels. A composite structural system comprising concrete lining， a flow control unit， and a pressure-regulating cavity was designed. The working principles and implementation methods of the adaptive lining under various operating scenarios were elaborated. Finally， laboratory-scale physical model tests were conducted to verify the performance and reliability of this technology under extreme conditions， including high internal and external water pressure， large deformation， and high geothermal environment. The proposed adaptive lining technology offers a unified solution for ensuring the safety of tunnel projects in complex environments， while also enriching the variety of lining types in tunnel engineering.