| With the development of economic and the continuous urban expansion, the urban traffic is deteriorated gradually, and the urban transport construction lands became more and more scarce. Urban underground highway is rising worldwide which can effectively alleviate the current traffic congestion and not occupy urban constraction lands, and also has the important role for national defense. However, the cross and interoperability is the first problem to be come across during a number of underground highways construction period. This thesis depends on "Analysis on Underground Interchange Tunnel Construction Technique" program, which belongs to the National High Technology Research and Development Program (863) issue.This thesis analysised the main tunnel construction programs, appropriate distance between the main tunnels in the interchange area, size of overall layout of the form and scale in underground interchange tunnel, the structure parameters optimization of main tunnels and branch tunnels, import and export reasonable position of the branch tunnels, the construction sequence and methods of the bifurcation, and so on. A new tunnel construction method, upper and lower interchange tunnel with zero distance, was put forward. The main works completed in this thesis are as followed:1. A variety of the main tunnel construction programs were proposed, after a comprehensive comparative analysis of multiple indicators by using the numerical simulation, obtained that the upper tunnels excavated separately first and then the lower tunnels excavated separately last was the optimal program.2. Tunnel models, adapting to underground interchange regions with different spacings (Horizontal & vertical), were built. The hole week and supporting internal force of those different main tunnels were studied, analyzed and summarized, and their respective regulations were obtained. By comprehensive comparative analysis, the optimal spacing adapting to Beijing geological conditions was given in this thesis.3.Taking the cross interchange for example, based on the stability of underground interchange structure and surrounding soil and the construction of the feasibility, the size of overall layout of the form and scale of underground interchange tunnels were put forward.4. Studyed on the profile and linear ramp of branch tunnel, the reasonable import and export position was determined based on the satisfaction of the stability of whole rock and structure of underground interchange tunnel; Three layout ways were proposed such as abrupt, tapered and stepped to the tunnel structure of speed change section, and their respective advantages and disadvantages were analyzed; Two programs were put forward to the construction sequence of the bifurcation tunnel, and the second program that construction from small space segment, arch segment to construction technology method of the step tapered section was the better. Construction methods of bifurcation sites spaced paragraph, the arch section and step tapered section were proposed.5. The Underground Interchange Structure Analysis System, used in the optimization calculation of the design of underground structures, was written by C# language. The Construction Monitoring Data Analysis Feedback System, used in grasping the dynamic deformation of rock and structure during the construction, was written by Java language. In this thesis, "dynamic design, dynamic construction" concept was realized by combing the two systems. 6. A new tunnel construction method, upper and lower interchange tunnels with zero distance, was put forward with the detailed construction method. One national invention patent was successfully applied based on this research, and the Application Number is 2010101050866.Compared with the general method, this new method has obvious advantage in the control of surface subsidence and support structure deformation, with little damage to the surrounding soil. The new method is suitable for Beijing and other cities which have the similar geological conditions.
|
PDF Full Text Request