Load Redistribution and Structural Response of Lined Rock Caverns for Compressed Air Energy Storage with Local Void Behind the Lining

A void between the concrete lining and surrounding rock interrupts the continuous support of lined rock caverns (LRCs) for compressed air energy storage (CAES). However, the load redistribution within the multilayer structure and the associated local response mechanisms remain unclear. This study focuses on a tunnel-type LRC with a steel liner as the sealing layer and develops a two-dimensional semi-analytical model considering local noncontact between the lining and surrounding rock. The model solves the segmented interface problem through substructural condensation, modal stiffness of the infinite surrounding rock, and Fourier point matching, and the results are numerically verified against two-dimensional finite element simulations. The results show that void behind lining induces spanning deformation of the lining and transfers the interface load to the intact contact zones on both sides. With increasing debonding extent, the spanning deformation, contact pressure near the boundaries, and circumferential stress of the steel liner continuously increase. The maximum spanning deformation occurs at the center of the debonding region, whereas the maximum tensile stress in the steel liner is located outside the debonding boundary, indicating that the local high stress is mainly related to load redistribution near the boundary. Under non-uniform in situ stresses, the structural response is jointly controlled by the initial cavern response and the local disturbance caused by debonding, and the unfavorable locations corresponding to deformation and steel liner stress are not identical. Parametric analysis further shows that concrete lining thickness and surrounding rock stiffness mainly reduce the debonding response by increasing the spanning stiffness and external support, while steel liner thickness mainly affects the stress level of the liner itself. The proposed method establishes a connection between local support loss, interface load redistribution, and sealing structure response, providing a theoretical basis for the mechanical analysis and defect evaluation of void behind lining in high-pressure LRCs.