Stability Analysis And Engineering Application Of Surrounding Rock With Small Net Distance Of Super Large Section

The rapid development of urban economic construction puts forward higher requirements for traffic infrastructure.In terms of tunnel construction,the number of existing lanes cannot meet the high-speed growth of traffic demand,and the two-way eight-lane tunnel has the advantage of large traffic volume,which perfectly solves this problem of urban traffic development.In this paper,based on the engineering background of the tunnel with small net distance in the super-large section of the high-speed daling around jinan city under construction,the mechanical effect of the construction process of the super-large section with small net distance in the tunnel was studied,and the following main results were obtained:(1)A numerical simulation study was carried out on the reinforced section and the general section of the lining of grade ? surrounding rock.At the same time,the plastic area distribution of surrounding rock shows that the plastic area of double sidewall tunnel is much smaller than that of CD and CRD.It is concluded that the method has obvious advantages in controlling the deformation of surrounding rock.According to the general section of iv-class surrounding rock lining,the construction method CD and CRD were adopted,and the displacement variation law and plastic zone distribution of surrounding rock were similar.The project cost,construction schedule and the difficulty degree of process were comprehensively considered,and finally the method CD was selected.(2)With small clear distance DaLing level ? surrounding rock of shallow buried tunnel segment as the engineering background,large 3 d visualization sectional model test system was developed and the surrounding rock is similar to "early"material,conducted a large model test of small clear distance tunnel construction process,to study the evolution law of surrounding rock displacement field,stress field,compared to verify the model test and numerical simulation results,the two results are consistent,which reveals the large section shallow-buried small clear distance tunnel construction in the process of the stability of surrounding rock.(3)Conducted DaLing shallow buried small clear distance tunnel level IV surrounding rock section of the site test,to study the deformation of surrounding rock and support system in the process of tunnel construction interaction law,mechanics analysis of the general lining strengthening segment level ? surrounding rock and lining segment of the deformation of the surrounding rock and supporting structure deformation law,combined with the site tunnel monitoring measurement data,common to confirm the reliability of the method under the conditions of different lining support optimization,to improve the construction quality,accelerate the progress of the realistic guiding significance.