Study On Application Of PHC Pile In Deep Foundation Pit

Prestressed high strength concrete pipe piles (shortened form PHC piles) are used and generalized rapidly all over the country because of their lots of virtues such as the high bearing capacity of single pile; low manufacturing cost; high speed construction and so on. Nowadays, in most of construction engineering, PHC piles are used as foundation piles and mainly bear vertical loads. Along with the development of city construction, increasing difficult problems are appearing in deep pit supporting, so a new deep pit supporting method which is on the safe side, high economy benefit, short construction period and environmental protection is needed.Recently years, PHC piles are tentatively used in deep pit supporting and mainly bear horizontal loads in many construction engineering. Some people don't support the new pit supporting method. But the practical applications indicate that PHC piles being used as pit supporting piles have good effects, especially in economy, construction period and environmental protection. In the paper, the feasibility that PHC piles are used in deep pit supporting is studied.PHC piles belong to partial soil-compacting piles and they often generate soil compacting effects around piles, which is different from the traditional pit supporting piles, because the traditional pit supporting piles such as artificial excavated pile, viro pile and so on are no-soil-compacting piles which don't generate soil compacting effects around piles. The soil-compacting of PHC piles can compress the soil around piles. Along with foundation ditch's excavation step by step, stress of soil in the side of excavation will be release which will cause the deformation and internal force's increment. So the soil compacting effects of PHC piles which are used in deep pit supporting are studied in the paper.PHC piles have lots of differences from other deep pit supporting piles. Structural particularity and construction speciality of PHC piles should be considered when the new pit supporting is designed. Some common theoretics and calculation methods are discussed, and according to these theoretics and calculation methods, the design methods which are suitable for PHC piles pit supporting are studied.At last, the feasibility and design methods of PHC piles pit supporting are further studied by two successful application examples in Wuhan.