Abstract
With the continuous advancement of trenchless technology, the application scope of rectangular pipe jacking construction has been continuously expanding. This paper takes the super-large cross-section rectangular pipe jacking construction with a middle partition wall for Fuzhou Metro Line 4 as an example, and elaborates on the impacts on pipe jacking construction resulting from the division of the tunnel into compartments by the precast middle partition wall within the pipe segments, as well as the corresponding countermeasures. The external outline dimensions of this pipe jacking tunnel are 10.8m×7.5m, with a wall thickness of 700mm and a standard pipe segment length of 1.5m; a 400mm-thick vertical middle partition wall is installed within a 131.122m interval. To address issues such as obstructed surveying sight lines and restricted spoil transportation caused by the presence of the middle partition wall, the project implemented measures including separation of personnel and vehicles and alternating dual muck boxes for spoil removal. This project represents the first domestic application of super-large cross-section rectangular pipe jacking construction in a metro section, and the pipe jacking technical measures presented herein can provide relevant experience for future similar projects employing pipe jacking methods for metro depot access lines, single-tunnel double-track sections, crossover sections, multi-compartment utility tunnels, and other engineering applications.
Full Text
A Brief Discussion on the Construction Technology of Ultra-Large Cross-Section Rectangular Pipe Jacking with Intermediate Walls
Zhang Yanhao
(Shanghai Tunnel Engineering Co., Ltd., Shanghai 200000, China)
Abstract
With the continuous advancement of trenchless technology, the application scope of rectangular pipe jacking construction has been steadily expanding. This paper examines the construction of an ultra-large cross-section rectangular pipe jacking project with intermediate walls for Fuzhou Metro Line 4, providing a detailed analysis of the construction impacts and corresponding mitigation measures resulting from the compartmentalization of the tunnel by precast intermediate walls within the pipe segments. The pipe jacking tunnel features external dimensions of 10.8m×7.5m, a wall thickness of 700mm, and standard pipe segment lengths of 1.5m. A 400mm-thick vertical intermediate wall was installed within a 131.122m section. The presence of the intermediate wall created challenges such as obstructed measurement sight lines and restricted muck transportation. To address these issues, the project implemented measures including separation of personnel and vehicle traffic and alternating muck removal using dual soil boxes. As the first domestic application of ultra-large cross-section rectangular pipe jacking technology for a metro section, the technical measures presented in this paper can serve as valuable reference for future similar projects involving metro access/departure lines, single-tunnel double-track sections, crossover sections, and multi-compartment utility tunnels.
Keywords: trenchless technology; metro section; intermediate wall tunnel compartmentalization; rectangular pipe jacking; construction technology