An expansion excavation structure and construction method for shield tunnel foundation

Abstract

The invention discloses an excavation expansion structure used on the foundation of a shield tunnel and a construction method thereof. The excavation expansion structure includes an arch frame at the contour line of the excavation expansion of the tunnel, a support structure connected to the segment inside the arch frame, and a support structure connected to the The support between the arch frame and the support structure; the support structure includes the cross section at the center of the tunnel excavation profile cross-section, the extension rods connected to the intersection of the cross section of the cross section, reinforcements and additional parts. The present invention carries out excavation expansion construction on the basis of shield tunnel construction, which is beneficial to saving man-hours and facilitating the installation of support structures in the early stage, and ensures the construction quality during excavation expansion; through the setting of support structures, it is beneficial to provide a support foundation during excavation expansion, and supports The cross frame on the structure can make the whole component uniformly stressed and adapt to different forms of design sections; through the setting of supports, it is beneficial to carry out synchronous support during the divisional expansion and excavation; through divisional excavation and top-down excavation, This ensures the orderliness of the expansion and excavation, which is conducive to ensuring the quality of the expansion and excavation.

Description

technical field [0001] The invention belongs to the technical field of rail transit construction, and in particular relates to an excavation expansion structure used on the foundation of a shield tunnel and a construction method thereof. Background technique [0002] In the process of urban rail construction, it is more and more common for shield subway tunnels to pass through urban areas. The "shield tunneling method" has the characteristics of high construction safety, fast construction speed, and less impact on the surrounding environment. Therefore, it has been increasingly used in subway construction. Wide range of applications. However, in the construction of tunnels with large cross-sections or different types of cross-sections, the shield method often cannot be completed in one step, and further excavation is required. [0003] Nowadays, the methods for expanding large-section or different types of tunnels in China mainly include CD method, CRD method and step metho...

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Problems solved by technology

[0004] The invention provides an excavation expansion structure and a construction method for shield tunnel foundation, which are used to solve the problem of excavation expansion construction on the basis of shield tunneling method, the support safety of excavation expansion construction, and the opening of excavation expansion construction. Technical issues such as excavation and connection sequence and reinforcement construction of special soil

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