Research On Optimization Design Of Standard Cross-section Selection Of Utility Tunnel

The utility tunnel is a box-culvert tunnels built underground the city to accommodate a variety of municipal pipelines.Utility tunnel is a new kind of important public infrastructure in urbanization which can significantly increase the capacity of urban infrastructure operation and the sustainable development capability of the city.The construction of utility tunnel can make overall plans for the design,construction and management of municipal pipelines,thereby avoiding problems such as the repeated excavation of roads caused by the laying of municipal pipelines,the messy of urban road overhead lines,and frequent accidents of municipal pipelines.It can also enhance the urban landscape,promote the intensive and efficient development of urban underground space,ensure the safe operation of urban infrastructure,and increase the core competitiveness of cities.At present,there are many technical problems in the construction process of utility tunnel in China.The cross-section design process of utility tunnel is immature.Designers often learn from existing utility tunnel cases at home and abroad or design just based on personal experience when determine the cross-section.Rationally intensive design of utility tunnel cross-sections facilitates the efficient use of utility tunnel space,saves construction costs,and satisfies urban sustainable development requirements for urban infrastructure.The selection and design of the cross-section of the utility tunnel mainly includes three aspects:the shape of the section,the number of cabins and the layout of sections.The design of the cross-section is closely related to the type,scale,and space requirements of the pipelines,it is one of the key technologies in the planning and design of utility tunnel.Reasonable standard section selection is conducive to the laying and adding pipelines and the maintaining and running the pipelines in the later period.It is one of the primary considerations in the planning and design of utility tunnel.The rational selection of cross-section can use urban underground space more efficiently,effectively save land resources,reduce the amount of work,improve project quality,shorten construction period,save costs,and have significant economic,environmental and social benefits.The main structure of the paper is as follows:(1)One of the key technologies in the design of utility tunnel is the selection and design of utility tunnel cross-section.This paper first summarizes the overview of the selection of utility tunnel at home and abroad and analyzes the main problems faced by the selection and design of the cross-section of domestic utility tunnel.(2)Using the analytic hierarchy process to determine the weights of social benefits,environmental benefits,and economic benefits for optimizing the selection of utility tunnel,The weight of the optimization of the selection is 0.350,0.394,and 0.256 respectively.determine the main direction of optimization based on economic efficiency and the cost components of utility tunnel.Cost analysis is performed for the utility tunnel with different sectional areas and cabin numbers.(3)The use of nonlinear planning analysis method based on economic benefits to optimize the size of the section.Firstly determined the constraint conditions for the standard section dimensions of the utility tunnel.Establish a non-linear plan to analyze the economic benefits of the steps and calculation methods.Combined with practical examples,an actual case analysis of urban underground utility tunnel was carried out,and improvement suggestions were put forward for the optimization of the integrated pipeline corridors in a northern city.Based on this,the size of the standard section was optimized through nonlinear programming,and the final section size was determined to be 12.38m~2,ensuring that the construction cost did not increase and that the initial section area increased by 12.54%.(4)The standard cross-sections of urban utility tunnel in the mountainous areas and the integrated pipeline corridors incorporating rainwater sewerage are optimized.