Abstract
The topography of submarine bedrock areas is rugged and uneven, characterized by alternating peaks and valleys with substantial dispersion in water depth data. Typically composed of moderately to slightly weathered granite, these formations exhibit high rock strength and complex terrain, necessitating special technical measures for construction in submarine bedrock protrusion zones to ensure safety and operational smoothness. This project runs parallel to the existing Zhuhai Bridge (a Class II bridge), precluding marine blasting pretreatment for the bedrock protrusion section according to the original design while maintaining normal traffic flow. Following consultation among all participating construction units and expert review, direct shield tunneling was adopted to traverse the bedrock protrusion section. Taking the pilot north line shield as an example, this paper investigates the tunneling technology for ultra-large diameter shields directly penetrating bedrock protrusion strata, addressing issues such as abnormal cutter wear, significant fluctuations in tunneling parameters, and difficulties in excavation face stability control through studies on cutter management, tunneling parameter control, and slurry circulation management, thereby providing a reference for subsequent ultra-large diameter shield construction in similar geological conditions.
Full Text
Analysis and Summary of Shield Tunneling Through Rock Protrusion Sections in the Zhuhai Tunnel Project
Zou Weitao, Liao Wenjiang, Dai Songlin
(Guangzhou Metro Engineering Consulting Co., Ltd., Guangzhou 510000, China)
Abstract
Submarine bedrock zones exhibit rugged and uneven topography with alternating peaks and valleys, characterized by high dispersion in water depth data. These formations typically comprise moderately to slightly weathered granite with high compressive strength and complex geological conditions. Such features necessitate specialized technical measures for construction in submarine bedrock protrusion areas to ensure operational safety and project success.
The Zhuhai Tunnel Project runs parallel to the existing Zhuhai Bridge (Class II), which precluded marine blasting pretreatment of the rock protrusion section under normal traffic conditions as originally designed. Following approval from all project participants and review by industry experts, direct shield tunneling was adopted to traverse the bedrock protrusion section.
This paper presents a case study of the pilot north-line shield, investigating the technology for super-large diameter shield tunneling through bedrock protrusion strata. It analyzes critical challenges encountered, including abnormal cutter wear, significant parameter fluctuations, and difficulties in excavation face stability control. The study focuses on key management aspects including cutter management, tunneling parameter optimization, and slurry circulation control. The findings provide a valuable reference for subsequent super-large diameter shield projects in similar geological conditions.
Keywords: super-large diameter shield; bedrock protrusion strata; cutter management; parameter control