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Hangzhou, China

Lin C.,Zhejiang University | Zhang Z.,Zhejiang University | Wu S.,Hangzhou Qing chun Road Cross river Tunnel Company Ltd | Wu S.,Hangzhou Yunhe Tunnel Co. | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

Additional thrust at the excavation face, friction force imposed on the around soils by shield skin and excess pressure of tail grouting can cause ground surface movements. Based on Mindlin solution, ground surface displacements induced by these three forces are calculated through numerical integration. The calculation results are verified by case studies of in-situ monitored ground surface movements in construction of Hangzhou Qingchun road river-crossing tunnel. The analysis results indicate that superposition of ground loss settlement and calculated movements due to above three forces based on Mindlin solution can be used to predict ground surface heave and subsidence induced by shield tunnelling. Ground surface heave of cross-section caused by shield tail synchronous grouting accords with Gaussian distribution. A modified Peck equation taking grouting impact into account is proposed. Compared with the conversional Peck method, modified Peck equation is able to predict ground surface heave induced by shield tunnelling; and the fitting parameters of ground surface subsidence through back analysis are more accurate.


Lin C.,Zhejiang University | Wu S.,Hangzhou Yunhe Tunnel Co. | Wu S.,Hangzhou Qing chun Road Cross river Tunnel Company Ltd | Zhang Z.,Zhejiang University | And 2 more authors.
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2012

Compared with conventional tunneling methods, ground movements behave some different patterns, such as surface heave induced by tail grouting. Through the analysis of ground surface heave due to tail grouting in three cases, the applicability of Gaussian equation and six analytic methods (including Mindlin's problem, Sagaseta method, Verruijt-Booker method, Loganathan-Poulos method, Chi method and Park method) to predict ground surface heave induced by tail grouting were verified. Based on case studies, one modified Peck equation was proposed to calculate ground surface movements, including grouting heave due to shield tunneling. The results show that the Gaussian equation and Chi method are applicable to calculate surface heave due to shield tail grouting, and the Modified Peck Equation can predict the total transversal ground surface movements rationally.


Lin C.,Zhejiang University | Wu S.,Hangzhou Qing chun Road Cross river Tunnel Company Ltd | Wu S.,Hangzhou Yunhe Tunnel Co. | Zhang Z.,Zhejiang University | And 5 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

During slurry shield tunnelling in silty sands during construction of Hangzhou Canal Tunnel, the cutter head of shield was trapped by sand adhesion. Due to the additional torque imposed by adherent sands, the cutter head stopped to rotate. The reasons for trap of shield's cutter head were analyzed, and the measures taken to relieve the cutter head were described. Based on experiences and lessons learned from this case study, measures to avoid trap of slurry shield's cutter head by adhesion of sands in silty sands were presented. In order to relieve the trapped cutter head, a pit was excavated at the front ground, and then high-pressure water jetting was used to clear sands adhered to the cutter head. Practice shows that the measures taken in this case were safe and effective for relieving the trapped shield's cutter head. Attention should be paid to ensure the safety of surrounding environments, especially the completed tunnel nearby when the pit is excavated. To avoid the cutter head of slurry shield being trapped by sands while tunnelling in silty sands, unobstructed and continuous slurry circulation should be maintained, high-quality slurry should be guaranteed to balance the excavating face, the ability to sweep away sands should be enhanced, and the cutter head should be rotated at set intervals when the shield stops to assemble the segmental linings.

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