Construction method of composite support system for inclined underneath passing of existing subway tunnel with extremely small clear distance

Abstract

The invention discloses a construction method of a composite support system for inclined underneath passing of an existing subway tunnel with an extremely small clear distance. The method comprises the following steps that an arch part of an underpass section adopts advanced pre-support through grouting by using an small guide pipe; an upper step is excavated in a non-explosion mode, and primary concrete spraying is performed on surrounding rock and a tunnel face; a grating steel frame is erected on the upper step, and a lower step gusset plate is reserved; hollow grouting anchor rods are arranged on the side walls, and foot-lock anchor pipes are arranged on arch feet at the left side and the right side of the upper step; expansion shell type anchor rods used for locking an upper step steel frame are arranged on arch feet at the left side and the right side of the upper step; and a lower step is excavated, and a lower step support structure is constructed. On the basis of the working condition of a long step method, a cantilever heading machine is used for non-explosion excavation, advanced support measures and locking measures between the upper step and the lower step are strengthened, settlement deformation of the existing operation subway is restrained, and the goals of simultaneity of operation and underpass excavation support is achieved.

Description

technical field [0001] The invention belongs to the field of urban rail transit engineering, and in particular relates to a construction method for obliquely passing through an existing subway tunnel composite support system with a very small net distance. Background technique [0002] With the rapid development of my country's subway construction, the subway operation network continues to form, and it is inevitable that the lines will cross each other. The tunnel excavation construction under the existing operating tunnel has obvious disturbance effects on the existing operating tunnel, which often leads to problems such as settlement, deformation and cracking of the lining structure, and emptying of the ballast bed in the existing operating tunnel, especially when the proposed tunnel is built with a minimum When the clear distance passes through the existing operating tunnel, it will cause obvious torsion effect of the existing operating tunnel, and uneven deformation will...

AI Technical Summary

Problems solved by technology

Based on relevant literature, at present, the domestic Beijing, Shanghai, and Guangzhou subway lines are well-developed, and most of the subways passing through the existing operating lines are constructed by the shield method. In the current situation, the tunnel support system needs to be different from the conventional subway underground excavation section tunnel, and more emphasis should be placed on the settlement and deformation control of the existing subway in operation. The existing research results and technologies cannot meet the actual needs of construction.

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