Research On Risk Management Of Shield Tunnel Construction In Qingdao Metro Line 4

With the increasingly prominent role of traffic congestion pressure in the process of urbanization construction,subway has been quickly become favored by cities due to its advantages of high efficiency,environmental protection and quickness.Subways in various cities have been planned and constructed successively,and are generally in the golden stage of rapid development.However,most of the actual construction sites of subway construction are located underground in the prosperous urban areas,which are significantly affected by the surrounding buildings,underground pipelines,geology and hydrology.At the same time,the entire construction process has distinctive high-risk characteristics such as strong professionalism and complex technology.As an indispensable leader among the many underground construction technologies of subways,the shield method is widely used in urban subway construction in China.Its technical uniqueness also increases the difficulty of risk control and the severity of loss.Therefore,it is stand need of attaching importance to and strengthening the study on risk management of shield construction in metro section.On the foundation of risk management theory,linked with the practical condition of Qingdao Metro Line 4,this paper uses the relevant data,methods and mathematical decision-making model to conduct study on the shield construction in metro sections.The main research contents are as follows:(1)On the foundation of systematically carding the research finding of experts and scholars in this field at home and abroad,this paper set forth the meaning,composition and general characteristics of metro construction risk.At the same time,it mainly introduces the relevant process of metro construction risk management.In addition,according to the technological development of the research object,this paper further summarizes the concept,classification,uniqueness and construction process of interval shield construction,which lays the foundation for the subsequent research.(2)From the four potential risk paths of subway construction risk occurrence mechanism,construction accident statistics,subway shield construction process and Qingdao similar shield construction experience,a detailed analysis and expression of shield construction risk factors are carried out.On the basis of introducing the SHEL model and expounding its applicability,based on the four link interfaces of the model:human and software(L-S),human and hardware(L-H),human and environment(L-E),and human and human(L-L).A risk evaluation index system suitable for shield tunnel construction of Qingdao Metro Line 4 is constructed.(3)Based on the analysis of the applicability of the research method,a combination weighting model based on the multiplicative synthesis method integrating AHP-rough set theory is determined.According to the subjective characteristics of the risk decision-making information sources and the spatial order of the defined risk levels,the unascertained measurement theory is introduced.Through the constructed unascertained measure function and single index measurement value,combined with matrix synthesis and confidence recognition criteria different from traditional judgment methods,a risk evaluation model for subway section shield construction is established.(4)Taking the actual project of shield construction between Jiushui East Road Station and Jinggang Road Station of Qingdao Metro Line 4 as an example,the risk assessment model of interval shield construction based on combination weighting and unascertained measurement theory is used to evaluate the overall and each link.The results show that the overall risk level belongs to level Ⅲ,interpreted as "general",and there is a tendency toward level "Ⅱ".At the same time,the corresponding risk control strategies are proposed for the key risk indicators at the bottom of each link system.This paper introduces SHEL model,combination weighting and unascertained measurement theory to study the risk management of shield construction in Qingdao Metro Line 4,aiming to provide new ideas and methods for effective evaluation of shield construction risk in subway section,and also provides a certain reference basis for future shield risk management research in Qingdao area or similar projects.