A mountain tunnel reconstruction expanding excavation construction method

Abstract

The invention provides a mountain tunnel reconstruction expanding excavation construction method. The method comprises the steps of performing expanding excavation support and construction according to tunnel construction standard requirements at sections without collapse cavities of a tunnel; performing detonation at sections with collapse cavities of the tunnel directly if the collapse cavities are smaller than a newly-constructed tunnel profile, and performing expanding excavation support and construction according to the tunnel construction standard requirements; if collapse cavities of the tunnel are larger than the newly-constructed tunnel profile, performing the following substeps on the sections with the collapse cavities of the tunnel: forming shed frames through pipe shed support and plate insertion for support in the sections of the tunnel, filling the collapse cavities outside the newly-constructed tunnel profile with light materials, and performing expanding excavation construction on the sections of the tunnel by using an improved expanding excavation support method. Compared with the prior art, the method directly analyzes tunnel collapse cavity construction risks by using the energy method, founds a macroscopic qualitative control method, formulates an implementation scheme, performs strict control, prevents adverse acting force and energy from transferring to or working intensively on weak parts of a structure, facilitates control of construction risks and guarantees engineering construction safety and quality.

Description

technical field [0001] The invention belongs to the field of construction methods, and in particular relates to a construction method for reconstruction and excavation of mountain tunnels. Background technique [0002] With the implementation of the national new-type urbanization plan (2014-2020), many small township road mountain tunnels built in the last century need to be rebuilt and expanded, and the construction quality of these tunnels is relatively poor, and there are even some collapse cavities of different sizes ( figure 1 ), bringing construction risks to reconstruction and expansion. Although there are many regulations in the existing tunnel codes, they do not explain from the concept of mechanics how to deal with the construction risk of tunnel cavity collapse of different sizes during tunnel reconstruction and expansion. However, it is very complicated and impractical to analyze the risk of tunnel collapse directly by engineering mechanics; it is relatively sim...

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Problems solved by technology

[0004] In view of the fact that the existing tunnel specifications do not explain from the concept of mechanics how to deal with the construction risks of tunnel collapses of different sizes during tunnel reconstruction and expansion, the invention directly uses the energy method to analyze the construction risks of tunnel collapses, and finds a solution to deal with the construction risks of tunnel collapses Control Method

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