Design Optimization Of Large Diameter Reinforced Concrete Culvert Shallow Buried In Water-rich Soil

Culverts are widely used in transportation, water conservancy, municipal construction and energy sectors. During preliminary design stage, design optimization can effectively control engineering cost and structural safety.In this thesis, Design optimization is carried out for the beach buried culvert project, which is part of the South-North Water Diversion Project in China. A coupled seepage-elastoplastic model for surrouding soil is established for FE analysis embeded culvert under various conditions, optimization results is also disscused.First, an extensive literature review is carried out on the theory of the design optimization of underground structures and coupled seepage-elastoplastic theory for porous media. Based on the geological reports and design drawing of the beach buried pipe,the research objectives are proposed.Second, On the basis of ABAQUS Python scripting language, A parameterized coupled seepage-elastoplastic analysis model is developed for the analysis of the culvert in the stage of construction, construction completion, operation, maintenance and flood conditions. MATLAB code is also deveoped for section design.Then, The Python script for ABAQUS and MATLAB code are integrated into Isight program to perform a multi-objective structural design optimization with Non-Dominated Sorting Genetic Algorithm-â…¡ (NSGA-â…¡) technique. The culvert wall thickness, rebar diameter and spacing are tailored for the structural performance and subjected to design constraints which are derived from the ultimate limit state analysis, service limit state analysis and detailing requirement.Finally, based on the optimization results and project, a3D analysis of the culvert -soil structure is carried out. Concrete damage plastic modle and rebar plastic modle are adopted for the renforced concrete culvert. The result of3D analysis shows that the structure meet limit state requirment.