Abstract:Focusing on the safety risks of in-service ship locks induced by underlying karst cavities,this study investigates the upper lock head of the Lianjiang Jietan hub ship lock through three-dimensional finite element modeling(FEM) and multi-scenario analysis to quantify the mechanical impacts of cavities and propose targeted reinforcement solutions.A refined 3D finite element model is developed using ANSYS software,incorporating the Drucker-Prager elastoplastic model for soil-rock foundations,SOLID65 elements to simulate concrete and masonry materials,and contact elements to characterize the interactions between the ship lock head and the foundation.The calculation results reveal that basal cavities induce stress redistribution,with tensile stress concentration in the left pier identified as the primary risk.It is recommended to fill the cavities pressure grouting combined with tensile zone reinforcement using carbon fiber-reinforced polymer (CFRP) sheets or steel lining plates.This research establishes a closed-loop “three-dimensional FEM-field monitoring” evaluation methodology,providing a quantitative framework for safety assessment of navigation locks in karst regions.The modeling approach,reinforcement strategies,and monitoring threshold criteria can offer references for similar projects,demonstrating practical value for extending service life and ensuring navigational safety.