Research on the Three-Dimensional Evolution Mechanism and Local Performance Evaluation of Reinforced Concrete Lining Crack Damage

Accurate detection of the internal damage of lining structures is a critical technology for assessing the structural health. Due to the complexity and concealed nature of tunnel structures, detecting internal damage faces numerous challenges. This paper focuses on large-scale reinforced concrete tunnel lining components. By collecting and analyzing the deformation, crack propagation, safety factor, and ultrasonic imaging data during the experimental process, the following main conclusions are drawn:(1) The load-bearing performance evolution of reinforced concrete tunnel linings exhibits distinct four-stage characteristics, namely the elastic, elastic-plastic, plastic, and failure stages.(2) Under the same vertical load, an increase in horizontal load significantly reduces the amplitude of the tensile strain of the component and substantially enhances the structural load-bearing capacity.(3) The crack propagation and evolution of the reinforced concrete lining show clear stages, including the crack initiation stage, Mode I crack propagation stage, Mode II crack propagation stage, and the compression zone failure stage. Initially, crack propagation corresponds to a gradual increase in load-bearing capacity, but when it penetrates the compression zone, there is a sharp decline in load-bearing capacity.(4) A multi-parameter comprehensive analysis method can effectively assess the structural load-bearing performance of reinforced concrete tunnel linings.