Variable cross section tunnel excavation construction method based on climbing pilot tunnel

Abstract

The invention discloses a variable cross section tunnel excavation construction method based on a climbing pilot tunnel. The variable cross section tunnel excavation construction method comprises thefollowing steps that 1, a small pilot tunnel climbing a slope and topping; topping from a small section to the center line direction of a large section tunnel by adopting a pilot tunnel mode, and digging the pilot tunnel obliquely upwards in an equal section manner until the pilot tunnel and an arch crown of the large section tunnel are positioned at the same elevation; 2, expanding and excavatinga transition section; continuing excavating the top of the pilot tunnel forwards to form the transition section; 3, excavating a standard section; excavating forwards from the transition section witha uniform section to form a working section of mechanical equipment; 4, excavating a transition section back; digging a middle step surface downwards on the horizontal plane of the transition section; 5, excavating the climbing section of the small pilot tunnel; expanding and excavating from the small pilot tunnel to the small section; and 6, excavating forwards from the variable cross section, forming a lower step surface, forming three steps, and constructing according to a three-step method. The construction time and cost are greatly reduced in variable cross section construction, and themethod can be widely applied to the field of building construction.

Description

technical field [0001] The invention relates to the field of building construction. More specifically, the present invention relates to a construction method for excavating variable-section tunnels based on climbing pilot tunnels. Background technique [0002] With the continuous development of my country's urban rail transit, the construction of the subway has entered a peak period. In order to meet the needs of track merging and diverging and other special conditions, the tunnel construction will encounter a sudden change in section from small to large. Due to the large gap between the height and width of the section, the construction will face upward lifting, which is risky. There are certain differences in lining types, support parameters and excavation methods, resulting in limited construction space and length, more irregular supports and temporary supports, and complex and difficult construction procedures. Contents of the invention [0003] The object of the pres...

AI Technical Summary

Problems solved by technology

In order to meet the needs of track merging and diverging and other special conditions, the tunnel construction will encounter a sudden change in section from small to large. Due to the large gap between the height and width of the section, the construction will face upward lifting, which is risky. There are certain differences in lining types, support parameters and excavation methods, resulting in limited construction space and length, more irregular supports and temporary supports, and complex and difficult construction procedures

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