Abstract
Screw-pile composite foundations have been widely implemented on multiple high-speed railways in China. Their distinctive design with variable sections makes the bearing behaviour of screw piles far more complex than that of common smooth piles. The bearing behaviour of a screw-pile composite foundation was analysed in silt soil on a national key construction project. A comparative analysis of the bearing characteristics of composite foundations of smooth piles and screw piles was performed through model tests. The results showed that, in a single-pile composite foundation and with the same pile diameter and length, the ultimate bearing capacity of the screw pile was 67% higher than that of the smooth pile. The smooth pile showed an area of negative frictional resistance at the top of the composite foundation. The screw pile had a negative friction area below the junction of the smooth section and the screw section in the screw-pile composite foundation.
Highlights
A screw pile is a variable-section pile that possesses a cylindrical upper part and a threaded lower part
Relative to full-screw filling piles and ordinary mud-retaining piles, screw piles have the advantages of high bearing capacity, wide applicability, fast pile forming, flexible size, no noise and no vibration, and have been widely used in the foundations of high-rise buildings
Relative to the cement–fly-ash–gravel piles and pipe piles commonly used in railway engineering, screw piles offer advantages such as the high bearing capacity of a single pile, low unit cost and so on, and have been applied in multiple high-speed railway projects such as the Beijing–Shanghai, Shijiazhuang– Jinan, Harbin–Mudanjiang and Zhengzhou–Xuzhou passenger railways currently operating in China (Deng, 2016; Liu, 2015; Wan, 2016)
Summary
A screw pile is a variable-section pile that possesses a cylindrical upper part and a threaded lower part. Considering the national key construction project of a new railway from Hohhot to Zhungeer, comparative analyses of the bearing capacity of smooth piles, screw piles and pile composite foundations were conducted using indoor model tests and numerical simulation.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
