(1. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China；2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；3. Shanghai Tunnel Engineering Co.，Ltd.，Shanghai 200232，China；4. Ningbo Rail Transit Group Co.，Ltd.，Ningbo，Zhejiang 315101，China)
Abstract：The tunneling in Ningbo，China, used the newly-developed quasi rectangle EPB shield and the superimposed stress was analyzed based on the Mindlin?s solution with the consideration of the excess pressure in front of the excavation face and the unevenly-distributed friction across the shield surface. Results show that the superimposed stresses are different from place to place in the soil layer. The soil in front of the cutter face is compressed，while the soil behind is under tension. The superimposed stresses in quasi rectangle shield tunneling are close to the ones in tunneling with the large diameter circular shield machines and are much smaller than the ones in DOT shield tunneling. The soil disturbance caused is thus easier to control.
2017, Vol. 36 
