Soil-tunnel interaction for segmental linings with non-planar longitudinal joints via centrifuge modeling

• A tunnel segment with non-planar, topologically interlocking joints is developed. • Soil-tunnel system response under asymmetric surcharge loading is quantified. • Enhanced kinematic constraints enable uniform internal forces distribution. • A stiffer soil-tunnel system improves serviceability and reduces settlements. • Delivers high-fidelity data and a strategy for more resilient segmental linings. Segmental tunnel linings can develop uneven internal forces and excessive deformation when nearby construction or groundwater fluctuations weaken their joints, threatening long-term durability. Conventional planar longitudinal joints often slip or rotate excessively under asymmetric, multidirectional loads, yet alternative geometries to overcome this vulnerability remain underexplored. This study proposes a novel design with non-planar, topologically interlocking longitudinal joints and evaluates its performance against a planar counterpart. A 50 g geotechnical centrifuge test imposed asymmetric surcharge loading on both linings. Ground responses, including surface settlement, soil stiffness, and stress redistribution, were monitored alongside structural responses such as bending moment and hoop force. The non-planar joints promoted more uniform hoop force distribution, limited peak bending moments, and stiffened the soil-tunnel system. Correspondingly, lining displacement and ground surface settlement decreased relative to the planar case. Key metrics, such as the load-sharing ratio and the equivalent radial spring stiffness of the system, quantify these performance gains. The high-fidelity dataset clarifies the load transfer mechanisms and supports the establishment of sophisticated numerical models required for comparative design optimization. These findings demonstrate that non-planar interlocking joints enhance system resilience and provide a practical pathway toward more robust segmental linings.