Study On Stability And Initial Support Mechanical Characteristics Of Surrounding Rock In Geological Structure Biased Tunnel

In recent years,in order to further meet the requirements of our national economic d evelopment,the construction of tunnel engineering has also stepped on a new step,which has challenged the more complex geological conditions.The number of geological structur e biased tunnels encountered during excavation is also increasing.On the basis of the su mmary of the existing research results,this paper uses the MIDAS/GTS NX finite elemen t software to carry out three-dimensional dynamic numerical simulation study on the whol e process of the tunnel construction under a variety of working conditions.In order to ha ve a more in-depth and clear understanding of the stability of surrounding rock and them echanical characteristics of the initial supporting structure of geological structure biased tu nnels.The main contents are as follows:(1)According to different tunnel construction methods,the difference of stress redistri bution of surrounding rock is caused by the difference between excavation sequence and support steps.With the help of MIDAS/GTS NX finite element software,three dimension al dynamic numerical simulation of the full section construction process of geological stru cture biased tunnels in the full section method construction and the upper and lower step method construction is carried out respectively.The influence of different construction meth ods on the stability of surrounding rock and the mechanical characteristics of initial supp ort of tunnel under geological structure biased tunnels is analyzed and the corresponding construction suggestions are given.(2)According to the structural properties of tunnel surrounding rock,several three-dim ensional numerical models are established based on different tunnel surrounding rock inter face angles.The numerical simulation of the construction process of multiple three-dimens ional numerical models with different angles of the surrounding rock interface is carried out and the results are compared and analyzed.The influence of surrounding rock and the mechanical characteristics of initial supporting structure of geological structure biased tu nnels under the different interface angles of the surrounding rock is systematically studie d.(3)According to the deformation characteristics caused by soft and hard surrounding rock,Several three-dimensional numerical simulation models are established on both sides of the tunnel surrounding rock interface respectively I and ? grade rock,I and III grade rock,I and IV grade rock under geological structures,The influence of surrounding rock and the mechanical characteristics of initial supporting structure of geological structure bi ased tunnels by the increase of the grade difference between the two sides of the tunnel surrounding rock interface and the regularity of the change are analyzed.