Optimization Of Shield Tunnel Deep Foundation Pit Support Based On Matter Element Model

With the growing development of urban modernization,high-rise(especially super-high-rise)buildings appear constantly,but the limited ground is hard to meet people’s requirements for efficient and convenient life.Therefore,people have turned their attention to the development and utilization of underground space.Underground projects(such as subways,underground pipe corridors,underground shopping malls,etc.)have been increasing in recent years,and the depth of foundation pits has also been increasing,thus the requirements for deep foundation pit engineering are becoming higher and higher.As an important project in deep foundation pit engineering,the supporting structure may be temporary,but it affects the progress,safety,cost and other factors of the whole project.Therefore,demonstrating and optimizing the construction plan of the deep foundation pit supporting project scientifically and reasonably have been an important topic.Based on the expert survey and reading a large number of literatures about related engineering evaluation index system,this paper analyzes the quality,safety,economy,environmental protection,construction period and other indicators from the relevant characteristics of the deep foundation pit support project,and establishes a set of multi-level evaluation index system of deep foundation pit support that is more scientific,reasonable,and accord with actual engineering characteristics.On this basis,based on the theory of extenics,the thesis fully considers the characteristics of actual engineering,and uses the matter-element analysis method to construct the optimal calculation model for the construction scheme of deep foundation pit support.Through expert review and analytic hierarchy process,the various indicators are quantified,and the weights and comprehensive relevance of each evaluation index are calculated by computer aided tools such as MATLAB.The system analysis and comprehensive evaluation of the primary selection scheme are carried out,and the preferred scheme is finally obtained.At the same time,the thesis combines theory with actual engineering.Taking the deep foundation pit engineering of the underground pipe gallery shield well in Shenyang as an example,combined with the local hydrogeological conditions and the surrounding environment characteristics,the parameters of the three primary selection schemes are input into the matter element.The calculation is carried out in the model,and finally the optimal support scheme of “steel structure inner support + support row pile + water stop curtain” is obtained,which is consistent with the actual project adopted,thus demonstrating that the matter element model has certain practical type..Finally,the dynamic monitoring and analysis of the steel support axial force,surface settlement,pile displacement and other data during the construction of the preferred scheme show that the indicators of the preferred scheme do not exceed the warning value,and the construction condition is safe and stable.From a new perspective,through the construction of the matter-element model,this paper optimizes the construction scheme of deep foundation pit support engineering of shield tunneling well,guides engineering practice with theory and provides a new solution for the selection of construction scheme of deep foundation pit support engineering.It certainly has application value.