A limit analysis method of shallow-buried shield tunnel ground uplift considering local failure of excavation face

A shield tunneling and excavation face technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of local passive damage development and less research on instability mechanisms

Pending Publication Date: 2018-12-28
BEIJING UNIV OF TECH
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Problems solved by technology

[0005] At present, the assumption of global passive instability has limitations in analyzing the local passive failure mode, and there are few studies on the development and instability mechanism of local passive failure

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  • A limit analysis method of shallow-buried shield tunnel ground uplift considering local failure of excavation face
  • A limit analysis method of shallow-buried shield tunnel ground uplift considering local failure of excavation face
  • A limit analysis method of shallow-buried shield tunnel ground uplift considering local failure of excavation face

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Embodiment Construction

[0136] Aiming at the problem of passive instability of the excavation face of shallow-buried shield tunnels in sandy soil, this patent proposes an analysis model that considers local damage, and conducts a series of numerical simulations. According to the calculation conditions in Table 1, the tunnel is analyzed. The influence of factors such as burial depth, diameter and formation friction angle on the local failure rate and ultimate support force are analyzed in detail as follows:

[0137] 1. To local instability ratio η

[0138] (1) Influence of tunnel depth (C)

[0139] When the tunnel diameter D and the friction angle remain constant, the influence law of the covering soil thickness C on the local instability height ratio η is calculated, as shown in Figure 8 shown. According to the theoretical results, with the increase of the covering soil thickness C, the local instability height ratio η has experienced a process of linear increase and then tends to be stable, and t...

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Abstract

The invention discloses a shallow-buried shield tunnel ground uplift limit analysis method considering local failure of excavation face, belonging to the shield construction technical field. Theoretical model research is mainly based on the assumption of overall instability of excavation face, but the passive failure of excavation face caused by excessive supporting force has a gradual evolution process from local failure to overall instability. The phenomenon of local passive instability and failure of excavated face has been found in the existing numerical simulations. At present, the globalpassive instability hypothesis is limited to analyze the local passive failure mode, and the research on the development and instability mechanism of local passive failure is less. The method assumesthe failure mode of soil mass and presents a theoretical model. According to the theoretical model, the theoretical formula is deduced. A numerical 3D model is established to calculate the local instability ratio Eta and the ultimate supporting force sigma T, and the results are compared with the theoretical model. The limit support pressure obtained by the local instability model provided by theinvention is smaller, and is closer to the result obtained by numerical simulation.

Description

technical field [0001] The invention relates to a method for analyzing the stratum uplift limit of a shallow-buried shield tunnel, in particular to a method for analyzing the stratum uplift limit of a shallow-buried shield tunnel considering local damage of an excavation surface, and belongs to the technical field of shield construction. Background technique [0002] The shield tunneling method has the advantages of little impact on urban buildings and high safety, and is one of the most commonly used construction methods in the construction of urban subway tunnels. In the construction of shield tunneling, maintaining the stability of the excavation surface is the basic premise of engineering construction safety. Among them, the setting of the support force of the excavation face is an important parameter related to the stability of the excavation face. If the support force is too small, it will cause active damage to the soil in front of the excavation face. The soil is pa...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/23
Inventor 李鹏飞陈柯屹王帆
Owner BEIJING UNIV OF TECH
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