Research On The Timing Of Secondary Lining Support In Zhonghecun Tunne

Comparing to the soft-rock tunnel,the deformation law of soft rock tunnel is relatively complex,its deformation is not after the excavation of a little time to complete,have stronger time effect;Due to the time effect of deformation of soft rock tunnel surrounding rock,tunnel secondary lining time becomes especially important,this paper takes the ZhongHeCun shallow buried large section of soft rock tunnel as the engineering background,using theoretical analysis and field testing,regression analysis and finite element numerical analysis methods for shallow buried large section of the second line of the soft rock tunnel supporting time study,and concluded the following conclusions:1.The tunnel through tunnel engineering information collection,investigation,site topography and geology,in-depth analysis of the geological background and the engineering geological conditions of tunnel site area,concluded the main factors of supporting time of second lining in soft rock shallow buried large section tunnel.2.Study on the stability of tunnel surrounding rock failure criteria,evaluation method and creep characteristic of soft rock mechanics characteristics and the tunnel lining support time,concluded the space-time change law of the surrounding rock displacement,stress and strain,laid a foundation to the research of second lining support time.3.According to the analysis of field test data,it is concluded the change law of tunnel vault subsidence and peripheral convergence;using Origin8.0 software obtains the best fitting function;based on the fitting function,combined with the relevant tunnel code,concluded the best supporting time of tunnel second lining of different sections.4.Taking the large general finite element software ABAQUS as analysis software.Respectively the length of the tunnel excavation height and the steps of the steps is optimized,the best size of step height and step length is obtained.Study on monitoring data inversion analysis of creep parameters,obtained for mudstone creep law of creep constitutive model of ZhongHeCun tunnel,and conducted the creep calculation,obtained the supporting time of the second lining.5.Through the engineering practice of institute of project of the second lining the optimal time of supporting verification,validation results show that,in this paper,the research results about second lining support time can be better applied to the engineering practice,the paper may have great help to solve the problem of similar engineering.