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Abstract Calculation of the rock pressure is still primarily based on the loose media theory，but the existing criteria cannot clearly define which class of surrounding rocks is the loose rock mass，producing the negative values in the calculating results. Meanwhile，the division of deep- and shallow-buried tunnels as an important issue is not still a final conclusion. Taking the rectangular tunnel with arch crown as the analysis object，the comparative analysis is carries out，and the difference of several methods of shallow-buried tunnel lies in stress analysis method，application of shearing strength theory and method for transforming lateral pressure of wedge body into earth pillar pressure. The basic condition of tunnel shape which can make sure to not produce negative value is obtained by using the formulae of Terzaghi，Xie Jiaxiao and Bierbaumer. Considering the advantages and disadvantages of existing division methods of deep- and shallow-buried tunnels comprehensively，the dividing line standard of deep- and shallow-buried tunnels is proposed which is between M. M. Promojiyfakonov law and Bierbaumer law. Taking the hole span as criterion，the fitting formula of correction factor which can consider comprehensive impact of cavity is built，and the rock mass mechanical parameters are considered in process of formula establishment.
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Received: 15 January 2010
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2011, Vol. 30 
