This paper presents an operating method of on the spot turn-around of a super large diameter shield machine which after break-in,ought to be turn-around,translated and returned for a second boring in opposite direction,in sharp contrast to the convention- al handling of disassembly after break-in,then lift-off and re-assembly of the shield for a second boring.

Based on the shield boring of the exit section of Shiziyang tunnel on Guangzhou-Shenzhen-Hongkong passenger-dedicated railway,the authors present the selection and optimization of the boring parameters,the control measures,boring process,difficulties and the countermeasures of the large-diameter slurry shield in water-rich soft ground with shallow cover.

The paper in detail introduced the key points of production technology quality control of the large-diameter shield segment, Combining with production technology of large-diameter and large volume segment Shield in the Nanjing Yangtze River Tunnel project, and provided specific control measures and solutions for key process quality control.