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Abstract A formula is derived to calculate the vertical earth pressure of circular tunnels in dense sand and hard clay grounds. The formula considers the coefficient of lateral pressure and the effect of oblique slip surface beside the circular tunnel on the basis of the hypothesis of Terzaghi theory. A method to calculate the lateral pressure coefficient is established in order to solve the proposed formula. A quantitative relationship between the vertical pressure and the factors such as the lining stiffness and the ground stiffness is also derived. The relationship shows that the decreasing of the lining thickness or the increasing of the elastic coefficient of resistance of ground lead to the increasing of the lateral pressure coefficient and the reducing of the vertical pressure. The results from the proposed method，the upper bound of limit analysis and previous experiment results are compared and found to be close to each other. The proposed method is simpler than the upper bound method and is suitable for both shallow circular and deep tunnels.
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Received: 27 May 2013
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2014, Vol. 33 
