Abstract: In the aim of investigating the sensitivity of rock-soil parameters during the deformation of gravity anchor excavation, FLAC^3D was employed to simulate the deformation based on orthogonal experiment design, and range analysis and variance analysis were conducted for the simulation results. The gravity anchor excavation of Fuma Yangtze River Brideg in Wanzhou District, Chongqing City, was selected as the research object. Results of range analysis and variance analysis both suggest that elastic modulus E₁, poisson’s ratio μ₁, cohesion c₁, and internal friction angle φ₁ of completely-weathered layer and elastic modulus E₂ of strongly-weathered sandy mudstone were identified as the dominant geotechnical parameters that affect the deformation of excavation. Furthermore in association with trial calculation results, E₁ and E₂ were determined as the target parameters of inversion analysis. The research results laid a foundation for subsequent displacement back analysis, provided guiding suggestion for controlling the deformation of excavation, and offered a reference for sensitivity analysis of similar engineering as well.

Key words: deep excavation project, sensitivity analysis, rock-soil parameters, orthogonal experiment method, statistical analysis