Research On Multi-objective Optimization Of Layout Scheme Of Narrow Construction Site Of Subway Station Based On NSGA-Ⅱ Algorithms

In recent years,subway projects have developed rapidly,alleviating many social contradictions in the process of urbanization.However,the layout of the construction site,which has a very important guiding role for subway projects,has not received the attention.The layout work is overly dependent on construction experience,which leads to a waste of construction resources and an increase in hidden dangers to the construction project.The surrounding environment is more polluted.Therefore,there is an urgent need to carry out research on the layout of the narrow construction site of subway stations,solve safety and environmental problems,and ensure the healthy and rapid development of the subway construction industry.By reviewing and summarizing existing studies,I find the limitations of existing studies.First of all,the research on the optimization of the layout of linear construction sites such as subways is very limited,especially on the optimization of the layout of small construction sites.Second,the existing research on the optimization of the layout of construction sites is limited to single-objective optimization and dual-objective optimization.Optimization,the research on optimizing three or more objectives is very lacking,and the existing research on site layout optimization mainly focuses on cost and safety,ignoring the construction activities on the construction environment and the production and living zone of construction personnel Influence.Aiming at the limitations of the existing research and the problems encountered in the optimization of the narrow construction site layout,a Pareto-based improved genetic algorithm was used as a technical method for multi-objective optimization problems to minimize the cost of resource flow at the construction site,the level of safety,and the level of environmental protection With the maximum as the goal,an optimization model for the layout scheme of a narrow construction site of a subway station based on the NSGA-II algorithm was established.In the study,the comprehensive relationship between facilities was quantitatively and qualitatively analyzed using the SLP method,and the relationship value of the objective function was determined.The multi-objective function was solved by MATLAB.At the same time,an evaluation system is established,and the best selection is evaluated based on the AHP-fuzzy comprehensive evaluation method,and a three-dimensional information model is established according to the optimal scheme.In addition,when determining the safety level between facilities,the factors that affect the safety level relationship between facilities are quantified to make the comprehensive relationship between safety levels more scientific and reasonable;and when determining the comprehensive relationship between environmental protection levels between facilities,carbon emissions,quantitative factors of noise and qualitative factors of dust,and the noise and dust generated during transportation between facilities are considered as factors affecting environmental protection.Finally,through actual cases to verify the applicability and effectiveness of the optimization model,and by comparing with the original site layout plan,the optimized plan can reduce resource flow costs by 7.8% to 21.3%,and improve safety levels by 2.8% to 7.2%,improve environmental protection level by 4.4% to 18.5%.According to the study,fully considering the characteristics of the subway station project,an optimization model for the layout scheme of the narrow construction site of the subway station was constructed,which enriched the research on the layout of the subway construction site.At the same time,based on the optimization of the location of the construction site facilities,the construction site management research The transformation from macro to micro has refined the research on construction engineering management;and put forward the research direction of improving the safety and environmental protection level of narrow construction sites from the perspective of optimizing the location of facilities in narrow construction sites to arrange management for narrow sites provided new ideas and enriched construction site management theory.