Novel estimation method for upward floating amount of dual-mode shield tunnel duct piece in upper-soft and lower-hard stratum

Abstract

The invention discloses a novel method for estimating the floating amount of a dual-mode shield tunnel segment in an upper-soft and lower-hard stratum, which comprises the following steps of calculating the floating amount of the segment under the condition of the upper-soft and lower-hard stratum, and calculating the floating amount of a segment structure caused by slurry buoyancy, and superposing the floating quantities of the two parts to obtain the floating quantity of the duct piece structure under the special condition. In the calculation of the first part, finite element software is adopted to establish a stratum-structure model, and the ratio of the elasticity modulus of the upper and lower stratums is used as a variable for analysis, so that the relationship between the floating amount and the ratio of the elasticity modulus of the upper and lower stratums is obtained; in the second part of calculation, finite element software is adopted to establish a load-structure model, and the ratio of upper and lower slurry pressure of the duct piece structure is used as a variable for analysis, so that the relationship between the floating amount and the ratio of the upper and lower slurry pressure is obtained. The floating amount of the duct piece structure under the stratum condition can be estimated according to the relation in follow-up actual engineering, and measures for controlling the floating of the duct piece can be reasonably selected according to the floating amounts of the two parts.

Description

technical field [0001] The invention belongs to the technical field of double-mode shield tunnel segment uplift, and in particular relates to a new method for estimating the uplift of shield tunnel segment due to buoyancy of slurry under the condition of upper soft and lower hard formations. Background technique [0002] With the rapid development of underground transportation, the number of subway tunnels has also increased. Considering the complex and changeable geological conditions, it is inevitable that the subway tunnels will pass through the upper soft and lower hard strata when planning the route, and the segment structure will also be formed. New stress and deformation forms, so the research on the stress and deformation laws of the segment structure is put on the agenda. [0003] Under the condition of upper soft and lower hard strata, the floating mechanism of the segment structure mainly has three aspects: First, the ratio of the elastic modulus of the upper and ...

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Problems solved by technology

However, this method does not consider the influence of upward additional stress and the uplift of the overlying soft soil due to the large difference in elastic modulus of the upper and lower strata after tunnel excavation and unloading, and does not consider the additional stress of the strata after unloading from a microscopic point of view. , so the result deviates from the actual

Moreover, when calculating the floating amount of the segment structure, the influence of the grout pressure at the top of the segment structure is often not considered, and only the buoyancy of the grout at the bottom of the segment structure is considered, which is not in line with the actual situation

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