The control technology of ultra-shallow buried large-diameter shield under-pass existing municipal tunnel at close distance

Abstract

Taking the left line of the section from Yunxi Park Station to Xiaojinzhong Station on Guangzhou Metro Line 12 as an example, the impact of large-diameter shield under-passing on the settlement and deformation of the existing municipal tunnel under complex geological conditions of upper soft and lower hard layers was investigated. By adopting protection measures and technical solutions at different stages, guidance was provided for the design and construction of the large-diameter shield under-passing. Based on the theoretical analysis, through the comparison and demonstration of the protection design scheme of Jinyuan Road Tunnel, the scheme of setting concrete box culvert at the deformation joint is finally determined. Based on the theoretical analysis, through the comparison and demonstration of the protection design scheme of Jinyuan Road Tunnel, the project adopted the scheme of setting concrete box culverts at the deformation joint. During the process of under-passing, measures such as excavation control, radial hole grouting, deep borehole grouting behind the segment, and increased monitoring frequency were taken, effectively solving the technical difficulties of settlement deformation control and providing reference for similar projects.

Keywords

large-diameter shield / close distance / underpass / upper soft and lower hard layers / settlement deformation