| Compared with Previous loess tunnel,the large-Span Loess tunnel is more Span andSmaller height-spanï¼ration，the Deformation Law of rock and distribution of plastic zone isdifferent with the previous loess tunnel.so study the deformation law of previous loess tunnelis necessary. with the support of dunliang tunnel, the graduate paper collecting relateddeformation data of three step sample method and two-side wall drift heading method. mainresearch contents and results.(1) Applying step sample method construct the large-Span Loess tunnel deformationdata,draw the curve with the normal curve of tunnel deformation space,from the time pointof view,the tunnel excavation,the first five days,the occurrence of settlement accounting forabout48.4%of the total settlement,30day settlement has been basically stable,convergencehas reached stability.In space,the tunnel face forward1D when the settlement of accounts forabout49.4%of the total settlement.From the tunnel face4D settlement has been basicallystable,convergence in order to achieve stability.top step sample emphasis would be laid oncontrol arch sink,middle step sample emphasis would be laid on control convergence.(2) Applying two-side wall drift heading method deformation data.Come to the tunneldeformation curve,the large deformation of the right guide hole on the left guide holedeformation and the deformation of the dominant hole clearance on both sides of the guidehole of each research section in the main tunnel excavation convergence values aredecreases,the research section of the arch settlement proportion in the closure of an averageof84.1%.constructs the large-Span Loess tunnel，two-side wall drift heading would be laidon control deformation.(3) Applying step sample method construct the large-Span Loess tunnel，the deformationlaw of rock consistent with Inverse trigonometric function. Inverse trigonometric functiveshould be predict for deformation law of rock, The percentage of deformation data in the allof deformation data after excavation face is82.6%.(4) Uses the MIDAS/GTS analysis software, has carried on the computation to the tunnelentrance section construction process, the computed result and the scene monitor data’ssoftware analysis result has carried on the contrast confirmation. large arch corner alternativefor system anchor in the large-Span Loess tunnel, tunnel structure is safety.According to the above research results. the dunLiang tunnel uses the supportingstructural style which may well control deformation, and guarantee supporting structure stability. The research resultswill have the guide and the reference value to the next similartunnel design and construction. |
