Abstract
Shield tunneling is increasingly applied in underground engineering construction due to its high safety and excellent construction efficiency. During long-distance tunneling in mixed ground conditions, extra-large diameter slurry shields are prone to muck accumulation and poor discharge at the front of the cutterhead, leading to deterioration of tunneling parameters, severe tool wear, and limited tunneling efficiency. If not controlled in a timely manner, this may even result in risks such as cutterhead clogging and loss of cutting capacity, over-excavation of strata, ground surface heave and settlement, and damage to main drive seals, seriously threatening construction safety. This paper introduces the cutterhead clogging conditions of extra-large diameter slurry shields employing two different types of cutterheads—atmospheric pressure and pressurized—during mixed ground tunneling for the Guangzhou Haizhuwan Tunnel project, analyzes the causes of mud cake formation, and proposes and applies a series of key technologies for mud cake prevention and control. Simultaneously, a comparative study is conducted on the service life of cutters, tunneling parameters, and tunneling efficiency between the two different cutterhead structural configurations. Practice demonstrates that the pressurized cutterhead shield machine exhibits significant advantages when tunneling in mixed ground conditions. The research findings can provide technical references for shield machine selection and construction in similar projects.
Full Text
Research and Practice on Mud Cake Analysis and Key Prevention and Control Technologies for Super-Large Diameter Slurry Shields with Different Cutter Head Types
Zhang Bo, Zhang Haibin, Lu Yangyi, Chen Zhao
Guangzhou Metro Engineering Consulting Co., Ltd., Guangzhou 510000, China
Abstract
Shield tunneling methods are increasingly employed in underground engineering due to their high safety and excellent construction efficiency. During long-distance tunneling in composite strata, super-large diameter slurry shields are prone to slag accumulation and poor discharge at the cutter head front, leading to deteriorated tunneling parameters, severe tool wear, and limited excavation efficiency. If not promptly controlled, this can result in mud cake formation on the cutter head, loss of cutting capacity, ground over-excavation, surface heave or settlement, and damage to main drive seals, posing serious threats to construction safety. This paper presents the mud cake conditions encountered during the construction of the Guangzhou Haizhuwan Tunnel using super-large diameter slurry shields equipped with two different cutter head types—atmospheric pressure and pressurized—when crossing composite strata. It analyzes the causes of mud cake formation and proposes and applies a series of key prevention and control technologies. Additionally, a comparative study on tool service life, tunneling parameters, and excavation efficiency between the two cutter head configurations demonstrates that the pressurized cutter head shield machine exhibits significant advantages in composite strata tunneling. The research findings can provide technical references for shield selection and construction in similar projects.
Keywords: super-large diameter; slurry shield; atmospheric pressure cutter head; pressurized cutter head; mud cake prevention and control