Safety Risk Management Analysis And Control Of Large-section Tunnels With Small Clear Spacing Crossing Complex Constructions (Structures)

Tunnel itself has a strong complexity and uncertainty,especially in the process of tunnel crossing the existing people’s air defend void,because of the influence of the people’s air defend void,the complex problem is made more risky.In addition,more reasons such as the large density of city construction,various forms of foundations and superstructures,all these reasons make a magnificent effect on the whole process of the tunnel construction.With the development of the tunnel construction in China,the situation will become more widespread,the problem which brings will become increasingly prominent.Research on tunnel passing through existing people’s air void and its influence on the surface construction and how to control this influence has a important theoretical and practical significance.This article is based on the Nanshan tunnel programme of Dalian Shengli Road.The surface buildings are concentrated near the tunnel,additionally complex people’s air void exist around it.Based on consulting a large number of domestic and foreign data,the article use the method which combines theoretical analysis,numerical simulation and field measurement,make a deep research on the basic theory which is involved by the urban tunnel crossing through people’s air void,moreover the research focus on the key technologies and kern problems which are involved,acquiring these achievements followed:1. A dynamic interaction system of small-distance tunnel-civil air defense-surface buildings is established, the interaction system is proposed including four aspects, it reveals the formation structure as the link between the three, it’s evolution law is the core of the whole interaction system.The root of the interaction of a dynamic interaction system of small-distance tunnel-civil air defense-surface buildings is the result of continuous transmission of stratum deformation caused by tunnel excavation, in order to analyze the correlation mechanism of the whole system, the influence of tunneling on the various elements in the system is studied by numerical calculation, according to the displacement distribution of the surrounding contour points of each element, some suggestions are given for the corresponding key control region.2. According to the assumption of reserved support,the research obtain the stress distribution rule and influencing factors on the section of reserved support under the circumstance of different hole diameters and different thickness of strata,and make a detailed analysis on the stress state of the middle rock pillar under different circumstances,including the average normal stress and bending stress,and make a detailed research on the disciplinarian of the central pillar stress distribution.On this basis,by using the complex variable function theory the research obtain the calculative method of the distribution rules of inner stress field in surrounding rock.3. Through the study of the existing partition criterion and numerical calculation,the research get the interactive relationship of people’s air defend void and new-built tunnels which have different space distribution rules geometric relations.Moreover,the influencing distribution of new-built tunnels passing through people’s air defend void is obtained,and the research make a further progress on the analysis of the interactive mechanism of tunnel-people’s air defend void-structure.4. Through the influencing factor analysis of security risk of tunnel passing through complex building group,the security risk evaluation index system is raised.Fuzzy mathematics is applied to the security risk evaluation of complex building group,and fuzzy comprehensive evaluation system which fits complex buildings is established,on the basis of that the research evaluates environmental safety risks of Nanshan Tunnel,meanwhile determines the security risk grade of the buildings influenced by the construction of the tunnel.5. The research establishes the finite difference model of buildings through the analysis of destructive model and relative constructive environment of different constructions,and compares various possible working conditions to get the environmental safety control standards related to existing buildings and people’s air defend void.The blasting environmental security control standard is strictly abide by the existing rules.6. By the means of theoretical analysis, numerical calculation and related engineering experience,the research decompose the total controlling value of complex building group deformation into every construction step under the optimal construction scheme,and distribute it into every construction step according to the deformation ratio of total control standards,establishing each stepwise deformation control standard.According to the deformation distribution standard of each construction step,it controls periodic environmental risks.