A construction method for cover and excavation of ultra-shallow buried tunnel

Abstract

The invention discloses an ultra-shallow buried tunnel cover-excavation construction method. According to the technical scheme, first, ground transportation for construction is evacuated; fender pile operation is performed on the two sides of an underground project to be implemented; a load-bearing beam and a structural top plate are manufactured on the top of a pile foundation, and then road surface traffic is restored; the position below the structural top plate is excavated to reach the elevation of a structural bottom in a three-step excavation mode, and soil supports between fender piles are constructed at the same time; a cushion layer and a bottom waterproof layer are reinforced; the major structure and the remaining waterproof layer of the underground project are implemented; sand is blown back so that a gap between a cover plate and the major structure can be backfilled with the sand. Compared with the prior art, the time for occupying a road because of construction is shortened, and influences on the external environment of construction are small; the horizontal displacement of the structure is small; the structural plate is used for excavation of a foundation pit so that a temporary support can be omitted; influences caused by external weather are small; the collapse risk of the ultra-shallow section underground project and the loss risk of a third party are avoided.

Description

technical field

[0001] The invention relates to a tunnel excavation construction method, in particular to an ultra-shallow tunnel cover-excavation construction method for passing through urban main roads or busy traffic areas, and belongs to the field of road and bridge engineering construction. Background technique

[0002] With the rapid development of urban subways, the difficulty of underground excavation projects is increasing. The thicker the covering layer on the top of the excavation, the more conducive to the construction of underground excavation, and the smaller the safety risk. The thinner the covering layer, the greater the safety risk. If the ratio of the actual measured earth pressure P to the vertical soil column rh is greater than or equal to 0.6 in the ultra-shallow backfill soil layer, and the ground traffic is heavy, no matter how advanced the pre-reinforcement is in the underground engineering construction, it is not allowed during the excavation process....

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