Deep buried pipe roof supporting effect evaluation method based on inter-pipe soil arch characteristics

Abstract

The invention provides an inter-pipe soil arch characteristic-based deeply-buried pipe curtain supporting effect evaluation method, which comprises the following steps of: firstly, analyzing transverse soil arch characteristics of a pipe curtain, and determining a load borne by the pipe curtain; then a pipe roof two-parameter elastic-plastic Pasternak foundation beam mechanical model is established, and an analytical expression of pipe roof deformation and internal force is obtained; a calculation formula of the bearing ratio of the surrounding rock to the primary support under the effect of the pipe roofing is provided, and the maximum deformation of the pipe roofing and the bearing ratio of the surrounding rock to the primary support under the specific working condition are obtained; and determining the allowable maximum deformation and the allowable minimum surrounding rock to initial support bearing ratio of the pipe roofing, comparing and evaluating the supporting effect of the pipe roofing under a specific working condition, and carrying out design optimization. According to the method, the stress of the pipe roofing advance support is obtained through scientific quantification, universality is achieved, the method is easily understood and accepted by designers, the pipe roofing stress of the soil arch characteristic between the adjacent pipe roofs is considered, the tunnel excavation safety is remarkably improved, and the construction cost is reduced. The bearing span reduction and load transmission effects of the pipe roofing are reasonably evaluated through the two index parameters of the maximum deformation of the pipe roofing and the bearing ratio of the surrounding rock to the initial support, the design construction parameters of the tunnel pipe roofing can be optimized, the overall performance of the pipe roofing support is fully played, and the scientificity and economical efficiency of the tunnel pipe roofing design are improved.

Description

technical field [0001] The invention relates to the technical field of tunnels and underground engineering, in particular to a method for evaluating the support effect of deep-buried pipe curtains based on the characteristics of soil arches between pipes. Background technique [0002] When long-span tunnels pass through unfavorable ground or pass through existing buildings, if effective engineering protection measures are not taken, it is very easy to cause serious accidents such as extrusion instability of the tunnel face, tunnel collapse and damage. Therefore, in the specific construction, in order to ensure the safety of the project, the pipe curtain is generally used to pre-reinforce the rock and soil in front, that is, the pipe curtain is advanced support, and the pipe curtain is used to bear the load of the loose rock and soil to prevent excessive deformation of the surrounding rock, thereby Reduce hidden risks. [0003] Under the existing technology, the action mode ...

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Problems solved by technology

[0004] However, most of the existing studies only qualitatively describe the effect of pipe curtain support, and seldom involve the quantitative analysis of the force mechanism and deflection distribution of pipe curtains.

In addition, the previous pipe curtain deformation calculation theory believed that the bearing range of the pipe curtain was only the area above the projection of the pipe diameter, and did not consider the characteristics of the soil arch between adjacent pipe curtains, resulting in obvious limitations, which are quite different from the actual situation

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