China Safety Science Journal ›› 2022, Vol. 32 ›› Issue (8): 84-90.doi: 10.16265/j.cnki.issn1003-3033.2022.08.1638

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Unified boundary determination method of pressure arch in tunnels and its spatial evolution characteristics

AN Yonglin1(), LI Jiahao1, LIU Wenjuan2, ZHOU Jin1, TAN Geyu1   

  1. 1 School of Civil Engineering, Hunan University of Science and Technology, Xiangtan Hunan 411201, China
    2 School of Material Science and Engineering, Hunan University of Science and Technology, Xiangtan Hunan 411201, China
  • Received:2022-02-21 Revised:2022-05-14 Online:2022-09-05 Published:2023-02-28

Abstract:

In order to analyse stability of surrounding rock after tunnel excavation, firstly, differences and similarities of inner and outer boundaries of pressure arch under different methods were investigated, and a unified method to determine arch boundaries was defined. Then, influence of different excavation methods on pressure arch was compared. Finally, a method to determine boundaries of three-dimensional pressure arch of the tunnel was proposed and evolution characteristics and shape of the arch were obtained under different excavation steps. The result shows as excavation step progresses, pressure arch gradually expands, which will be the smallest for Center Diaphragm(CD) method. The three-dimensional pressure arch range is smaller than that of two-dimensional one, and its shape gradually changes from a small trumpet due to spatial constraints of the tunnel face, while its height and width also gradually increase. During tunnel construction, segment process control can be achieved by adopting subsection excavation method, and space constraint of the tunnel face can be utilized to ensure safe construction.

Key words: tunnel, pressure arch, boundary determination method, spatial evolution characteristics, construction safety