Compound stratum shield tunnel vault load calculation method

Abstract

The invention relates to a compound stratum shield tunnel vault load calculation method. The method comprises the following steps of obtaining an actual thickness value of a first soil layer located at the upper part and arranged on an excavation face of a shield tunnel according to an exploration material; by utilizing a critical thickness calculation formula, calculating a critical thickness value of the first soil layer when the slip surface width of the first soil layer located at the upper part and arranged on the excavation face of the shield tunnel is equal to the slip surface width of a second soil layer located at the lower part; and performing comparative judgment: if the actual thickness value of the first soil layer is smaller than or equal to the critical thickness value, calculating a vertical soil pressure of a tunnel vault by utilizing the slip surface width of the second soil layer, and if the actual thickness value of the first soil layer is greater than the critical thickness value, calculating the vertical soil pressure of the tunnel vault by utilizing the slip surface width of the first soil layer. According to the method, the actual condition of a compound stratum is considered, so that deformation and stress conditions of segments can be reflected more accurately and a foundation is provided for accurately calculating internal forces of shield tunnel segments.

Description

technical field [0001] The invention relates to the field of internal force calculation of tunnel segment structures, in particular to a method for calculating the vault load of a shield tunnel in a compound stratum. Background technique [0002] At present, most domestic calculations of the internal force of tunnel segment structures using the shield tunneling method use the modified customary method. The modified idiom assumes that the structure is an elastic homogeneous body, and considering the existence of circular joints, the overall bending stiffness of the ring is reduced, such as figure 1 As shown, take the bending stiffness of the ring as ηEI. Correct the loads on the tunnel structure in the usual usage such as figure 1 shown, including the vertical earth pressure q of the vault 1 , back arch earth pressure q G , top and bottom horizontal earth pressure e 1 and e 2 , lining weight g, hydrostatic pressure q w , bottom vertical reaction force q 2 , Horizontal...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects of the prior art, to provide a method for calculating the vault load of a shield tunnel in a composite stratum, and to solve the problem of using the Terzaghi loosened earth pressure formula to calculate the vertical earth pressure of the vault in the prior art due to the fact that it is based on a uniform stratum. The large error caused by the calculation does not meet the accuracy requirements

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