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.

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.

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.

Three-dimensional finite-difference program is used for simulation of large diameter shield tunnel.