| Based on the simple analysis of the mechanism of surface subsidence caused by the construction of shallow buried excavation,the factors that affect the surface settlement are summarized.Taking Urumqi Metro Line 1 Three-New district as an example,the data collection monitoring section,focusing on the excavation method,the overlying soil lithology,buried depth of the tunnel axis and other factors were discussed,analysis of different factors on the effect of surface subsidence,summarizes the regularity of surface tunnel construction under different settlement influence factors.Then,to further explore the variation of prediction parameters Peck method and stochastic medium method,through the screening of range of typical monitoring section data,verify the applicability of the method in Urumqi area,and is used to predict the parameters of Peck equation and stochastic medium method in inversion,and fitted out fitting empirical formula of measured data the region based on engineering.The conclusions are as follows:(1)Each section of the tunnel excavation and the resulting lateral surface settlement trough,the shape of a single peak,basically consistent with the Gauss normal distribution curve;Peck formula in the prediction of large cross-section tunnel has good applicability.(2)In the use of medium method for surface subsidence prediction immediately,in order to make it suitable for shallow and large section tunnel,the convergence model is modified,considering that the tunnel bottom uplift of the non-uniform convergence mode,the engineering examples show that the convergence mode compared to the original traditional model has a better prediction precision high.(3)The empirical values of the location of the reverse bend point,the formation loss rate,the convergence radius of the section,the central displacement of the section and the influence angle are fitted.The reference is provided for the subsequent construction of Urumqi metro. |
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