Abstract
With the widespread application of shield tunneling technology in complex hard rock strata, the impact of cutter housing assembly configurations in atmospheric pressure cutterhead shield machines on construction efficiency and safety has become increasingly prominent. This paper investigates the Guangzhou Haizhuwan Tunnel Project, systematically comparing and analyzing the application differences between front-loading cutter housings (C-block mechanical self-locking structure) and rear-loading cutter housings (multi-stage bolted connection structure) regarding abnormal damage modes, tool change efficiency, and service life, under geological conditions featuring argillaceous siltstone with uniaxial compressive strength reaching 101 MPa. The study reveals that front-loading cutter housings effectively disperse dynamic rock-breaking loads through integrated structural design, significantly reducing abnormal damage rates during hard rock excavation, with no systematic failures such as lock detachment or bolt fracture occurring. The assembly process demonstrates high visualization, enhancing tool change efficiency by approximately 38%-54% compared to rear-loading configurations. Field engineering data indicates that front-loading cutters achieve an average service life extension of approximately 50%, and in conjunction with mechanical self-locking characteristics, can establish a "high-efficiency-low-risk" positive cyclic effect, increasing daily excavation progress by 65% in hard rock sections and achieving a 44% monthly progress increase in upper-soft lower-hard strata. By contrast, rear-loading cutter housings constitute a weak link in hard rock construction due to reliability deficiencies in the bolted connection system under high-frequency vibration. The research findings demonstrate that front-loading cutter housings should be prioritized in hard rock strata to improve construction stability and economic viability, whereas rear-loading cutter housings require anti-vibration improvement measures to meet the demands of composite strata. This study provides a practical foundation and technical paradigm for cutter system selection in atmospheric pressure cutterhead shield machines operating in complex rock formations.
Full Text
Preamble
Analysis of Application Performance of Front-Mounted and Rear-Mounted Disc Cutter Assemblies on Shield Machines in Hard Rock Formations
Lu Yangyi, Zhang Haibin, Zhang Bo, Li Peitao, Zhan Chun
(Guangzhou Metro Engineering Consulting Co., Ltd., Guangzhou 510000, China)
Abstract
As shield tunneling technology becomes increasingly deployed in complex hard rock formations, the disc cutter assembly configuration on atmospheric pressure cutterhead shield machines has emerged as a critical determinant of construction efficiency and safety. This study systematically compares the application performance of front-mounted disc cutter assemblies (featuring a C-block mechanical self-locking structure) and rear-mounted disc cutter assemblies (utilizing a multi-level bolt connection system) through the case study of the Guangzhou Haizhuwan Tunnel Project. The project involves excavation through argillaceous siltstone formations with uniaxial compressive strengths reaching 101 MPa, providing an ideal context for analyzing differences in abnormal damage modes, cutter replacement efficiency, and service life.
The research reveals that the front-mounted cutter assembly effectively distributes dynamic rock-breaking loads through its integrated structural design, significantly reducing abnormal damage rates without experiencing systematic failures such as lock detachment or bolt fracture. Its highly visible assembly process yields a 38–54% improvement in cutter replacement efficiency compared to rear-mounted systems. Field data demonstrate that front-mounted cutters achieve approximately 50% longer average service life, and when combined with the mechanical self-locking feature, create a positive feedback loop of "high efficiency, low risk." This translates to a 65% increase in daily advance rates in hard rock sections and a 44% monthly progress improvement in upper-soft lower-hard formations. In contrast, the rear-mounted cutter assembly represents a weak link in hard rock construction due to reliability deficiencies in its bolt connection system under high-frequency vibration. The findings indicate that front-mounted disc cutters should be prioritized for hard rock formations to enhance construction stability and economy, while rear-mounted configurations require anti-vibration improvements to meet the demands of composite ground conditions. This research provides practical guidance and a technical paradigm for cutter system selection in atmospheric pressure shield machines operating in complex rock strata.
Keywords: front-mounted disc cutter assembly; rear-mounted disc cutter assembly; hard rock formation; abnormal damage; service life; comparative analysis