Existing tunnel crossing system based on underground excavation pilot tunnel and jump excavation vertical shaft and construction method

Abstract

The invention discloses an existing tunnel crossing system based on an underground excavation pilot tunnel and a jump excavation vertical shaft and a construction method. A newly-built tunnel is constructed by crossing an existing tunnel, an existing treatment method is a mode that the vertical clear distance between the newly-built tunnel and an existing underlying tunnel is properly increased, a soil clamping body stratum is subjected to grouting reinforcement treatment and the like, the effect of the method is difficult to guarantee, and the construction cost is high. A newly-built tunnel is arranged above an existing tunnel, the area, overlapped with the projection of the existing tunnel, of the newly-built tunnel is a vertical shaft arrangement range, and in the vertical shaft arrangement range, the upper half section of the newly-built tunnel is a pilot tunnel, and the lower half section of the newly-built tunnel is a vertical shaft; and outside the vertical shaft arrangement range, the upper and lower sections of the newly-built tunnel are pilot tunnel structures. In the excavation process of all the areas of the vertical shaft, it can be guaranteed that the existing tunnel below can obtain effective ballasting, then springback or upheaval deformation of the existing tunnel is controlled, the technology is simple, construction is easy and convenient, and the method has wide application prospects in tunnel crossing projects.

Description

technical field [0001] The invention belongs to the technical field of underground engineering, and in particular relates to an existing tunnel spanning system and construction method based on a buried pilot tunnel and a jump-dug vertical shaft. Background technique [0002] At present, with the start of a new round of urban rail transit construction and planning projects in various places, construction of various types of crossing existing operating tunnels has gradually become the norm, but the current level of technology is difficult to fully guarantee the safety of existing operating tunnels during crossing construction. Therefore, the close construction of existing lines including spanning has become a major technical problem that needs to be broken through urgently. [0003] Under normal conditions, when a new tunnel is built across an existing operating tunnel, the excavation of the new tunnel will inevitably lead to the unloading of the tunnel arch bottom and the upl...

AI Technical Summary

Problems solved by technology

[0002] At present, with the start of a new round of urban rail transit construction and planning projects in various places, construction of various types of crossing existing operating tunnels has gradually become the norm, but the current level of technology is difficult to fully guarantee the safety of existing operating tunnels during crossing construction. Therefore, the close construction of existing lines including spanning is a major technical problem that urgently needs to be broken through

[0003] Under normal conditions, when a new tunnel is built across an existing operating tunnel, the excavation of the new tunnel will inevitably lead to the unloading of the tunnel arch bottom and the uplift deformation of the underlying tunnel. The impact of surrounding traffic and adjacent structures (such as underground pipelines) is inevitable, sometimes even causing serious environmental damage

Excessive excavation and unloading will seriously affect the safe operation of the existing tunnels. At present, the commonly used treatment methods are to properly extend the vertical clearance between the new tunnel and the existing underlying tunnel, grouting reinforcement in the interbedded soil strata, and The above method is not only difficult to guarantee the implementation effect, but also the construction cost is high

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