Control of the Shield's Vertical Attitude During Shield Tunnelling in Soft Soils
(1 College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058; 2 Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058; 3 College of Civil, Construction and Environmental Engineering, Ningbo University, Ningbo 315211; 4 Hangzhou Metro Group Co. Ltd., Hangzhou 31000)
Abstract：
It is inevitable for a shield to deviate from the designed route during tunnelling in soft soils, which may result in the concentration of stress in segments, segment cracking and excessive ground settlement. Based on measured data from a shield tunnel of the Hangzhou metro project, this paper analyzes the shield's vertical attitude variation in a typical Hangzhou soft-soil layer and gives corresponding control measures. The results show that: 1) it is inevitable for the shield to be tilted with a negative pitch angle during segment erection; 2) during shield driving, an effective way of adjusting the pitch angle is to control the deviation correction moment since the pitch angle is sensitive to deviation correction moment variation; and 3) adjustment of the shield attitude is a dynamic process, so it needs to be planned in detail and implemented patiently.
2015, Vol. 52 