Comparative Study On The Shallow Tunnel Of A Subway Tunnel Design Method

First in this paper, based on the understanding of metro tunnel construction method,mainly summarized the shallow tunnel construction method of tunnel and supportingtheory. I as an intern for the enterprise, by participating in the Beijing subway project inthe design and calculation, found that the shallow depth excavation design used in thecalculation of a subway tunnel method has disadvantages. So the purpose of this articleis set in Beijing metro as an example, respectively by using load structure method andthe analysis of stratigraphic structure method to calculate the stress of the liningdeformation, by comparing the analysis result of both cases, and the difference betweenthe two methods, the applicable scope and the advantages and disadvantages of each.Theoretically, load structure method that structure surrounding rock mass andstructures are independent of each other, equivalent to exert active load on structures ingeotechnical engineering; And stratigraphic method that rock mass structure andstructure are integrated as a whole, considering the interaction of both.After theoretical analysis, this article also according to actual circumstances,establish underground structure and the soil parameters of soft soil and hard soil, withthe load structure method and stratum structure method, respectively, calculated in thehard soil and soft soil structure of the internal force values, shows that stratum structuremethod to calculate the internal force values smaller than load structure method tocalculate, this is transverse contrast; After longitudinal comparison at the same time,also found that stratum structure model calculated internal forces in the soft soil in valuerather than on hard soil internal force values of the difference in the calculated soil thanthe load-structure model in two draw internal force difference is big, the change of soil parameters in formation-structure model of the impact is greater than the effect of load-structure model.At the end of the paper is set in Beijing engineering examples, respectively usingthe method of load structure method and stratum structure calculation analysis of asubway station. Because of Beijing hard soil, the calculation results compared with theresults in previous chapter hard soil, can be found in front of the actual situationconforms to the conclusion. Namely in hard soil, the stratum structure method tocalculate the internal force values smaller than load structure method to calculate.To sum up, load structure method, simple and convenient calculation due toaffected by floating formation parameters change is not very big, is now a designer ismostly used method, but relatively conservative load structure method, calculationresults is larger; Strict stratum structure method for the accuracy of the parameters,some parameter is difficult to determine, even application up has the certain difficulty,but the formation structure method is more realistic, the calculation results moreaccurate load structure method, so it can save construction cost. And with thedevelopment of modern information technology, formation structure method increasesgradually, the application scope of the method should be designed to be used in method.