| Along with the accelerating construction pace in China, emerge a variety of across-sea/river underwater tunneling projects, inevitably entailing an emphasis on the coupling interaction between the seepage field and the stress field, for which, in spite of the fact that it has been increasingly paid attention to nowadays, but test researches and theoretical methodology are still to be worked on, especially in case that the combined action between wall rocks and shoring structures with the fluid-solid coupling effects should be taken into accounts simultaneously. This paper presents a model study on Liuyang River Underwater Tunnel of Xiang River Road in Changsha City as the following:1. Expounded the basic equation for saturated seepage in porous media basing on the seepage continuity equation and the seepage movement equation, and gave forth a group of partial differential equations for seepage in fluid-solid coupling cases and the deterministic condition of solution inferred from the Biot Consolidation Theory.2. Introduced the representation of each equation for fluid-solid coupling interaction in the three-dimensional differential procedure FLAC3D, and the general modeling methods in FLAC3D for solution.3. Simulated the construction of Liuyang River Underwater Tunnel basing on FLAC3D numerical methods, improved upon the traditional numerical methods in representing fluid-solid coupling effects, taking accounts of both the fluid-solid coupling effects and the combined action of wall rocks and shoring structures, established fluid-solid coupling models to represent soil-rock mechanical characteristics and water flow, and analyzed the mechanical effects of the underwater tunnel during each construction stage.4. Analyzed and compared the measured data of Liuyang River Underwater Tunnel with the numerical results, estimate the reasonableness of numerical simulation, and evaluate the safety of tunneling works basing on surveyed data so as to ensure safe construction. |
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