Method for distinguishing stability of tunnel at different construction stages

Abstract

The invention discloses a method for distinguishing the stability of a tunnel at different construction stages. According to the method, a new concept, namely a surrounding rock yield volume ratio, capable of reflecting the tunnel surrounding rock engineering mechanical characteristics and influence of tunnel excavation and supporting effects is provided, the mechanical characteristic, which is anexcavated tunnel deformation gradually developing process, namely a surrounding rock stress gradually releasing process, is utilized, the variation curve of the surrounding rock yield volume ratio along with a surrounding rock stress release rate after the tunnel excavation at a certain construction stage is established, and the stability of the tunnel at that construction stage can be determinedby utilizing the mutation characteristics of the curve. The method has the advantages of clear and simple physical concept, convenience in use, reliable result and the like, and is suitable for popularization and application in construction safety management of engineering under highway tunnels, railway tunnels, hydraulic tunnels, municipal tunnels and the like.

Description

technical field [0001] The present invention relates to a method for judging the stability of tunnels in different construction stages, in particular to the stability of mountain tunnels (roads, railways), municipal tunnels and water diversion tunnels constructed in strata and constructed by underground excavation in different construction stages. method of discrimination. Background technique [0002] The underground excavation method is used to construct tunnels, and generally, divisional construction methods are used, such as the positive step method and the three-step method. The main feature of divisional construction is to divide the tunnel into several construction stages. For example, the positive step method divides the tunnel into upper step construction, lower step construction, inverted arch closure and pouring tunnel lining structure, etc., while the three step method divides the tunnel into upper step construction. , middle step construction, lower step constr...

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Problems solved by technology

Therefore, there are still problems when using this method to judge the stability of the tunnel.

and take advantage of figure 1 When the theoretical characteristic curve of the surrounding rock in the principle of the convergence-limit method shown above is used to judge the stability of the tunnel, the lowest point G of the characteristic curve is often difficult to determine, and the curve on the right side of the G point cannot be determined numerically, that is, The inflection point of the characteristic curve method cannot be determined

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