| The softening of water-rich mudstone is very fast after excavation,which produces a lot of problems,and has been perplexing the tunnel builders for a long time.This paper relies on Mudanjiang Shuangfeng tunnel project,getting the deformation law of water-rich mudstone tunnel by the analysis of monitoring measurement data on construction site first of all.Secondly,combined with the understanding of cusp catastrophe theory and deformation control theory,by using the finite element software to find the ultimate displacement of deformation of Shuangfeng tunnel,and putting forward the deformation control datum of Shuangfeng tunnel.Finally,using numerical simulation analysis to analyze the different deformation control measures and selecting the optimal deformation control measures accord to the results,at the same time studying the drainage and decrease water pressure technology of Shuangfeng tunnel and select the best scheme.The main work and results are as follows:(1)Through the analyze the deformation and the stress of the supporting structure of Shuangfeng tunnel which is based on monitoring measurement data on construction site,the results show that the deformation rate of Shuangfeng tunnel is fast and the duration is long,the surrounding rock pressure is asymmetric which makes the stress of the supporting structure show asymmetry.(2)By analyzing the law of plastic strain of the hole under the different stress release coefficient and found the limit state of stability of surrounding rock,through the research of cusp catastrophe theory and combined with numerical simulation.Afterwards taking the classification of the surrounding rock deformation control standards on the basis of Three-level Management System and proposed the deformation control criterion of tunnel.(3)The result which is based on the analysis of water-rich mudstone tunnel deformation characteristics show that the perturbation range caused by the excavation of water-rich mudstone tunnel is wider,the loose zone,strength reduction zone or compaction zone caused by the excavation appeared alternately and the lateral deformation of mudstone is more sensitivity to the confining pressure compare with the axial deformation.(4)Through proposing the targeted deformation control measures and analyzing different deformation control measures comparely by using the numerical simulation,based on analysis of the deformation characteristics and actual monitoring of the water-rich mudstone tunnel.Different deformation control measures include different step heights,different step lengths,different lock pin anchor pipe combinations,different longitudinal connections and so on.The conclusion suggest that the step height of 3.5 m,the step length of 5 m,the two 6 m long with 89 anchor pipes combination and 14#U-bar for longitudinal connection through the optimization analysis.(5)By using the Madis-GTS software to analyze the drainage and decrease water pressure scheme which include the double wells scheme and the double drain hole scheme.The results show that the double wells scheme’s total drainage quantity is larger,which consumes shorter time to reach steady stream,and it is more conducive to the construction of the tunnel in later stage. |
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