桩靴形式对PHC桩穿透性能的影响

坦桑尼亚某水工项目桩基施工采用直径800和1 000 mm两种类型的PHC桩,针对不同桩靴形式的基桩穿透性能进行研究。从桩尖形式、桩靴长度、钢桩靴与PHC桩连接方式对PHC桩沉桩总锤击数、贯入度变化进行统计,结合不同桩靴形式在相同地质条件下的贯入度、桩身应力、能量等参数进行对比。结果表明,外突十字桩尖PHC桩穿透性能最强;桩靴长度增加其基桩穿透能力增加,但桩靴长度大于5 m时,其基桩穿透能力增加不明显;钢桩靴与PHC桩法兰盘采用斜角坡板焊接能减少沉桩过程土阻力,基桩贯入度较大,更易穿透至设计高程。

Influence of different pile shoes on penetration performance of PHC pile

Two types of PHC piles with diameters of 800 mm and 1000 mm are used in a hydraulic project in Tanzania.We study the penetration performance of foundation pile with the different pile shoes,gather the total blow number and set from PHC pile construction,PHC pile shoe length and the connection method of PHC pile flange with pile shoe,and compare the set,pile body stress and energy of different pile tip forms to enter the same soil layer under the same geological conditions.The results show that the penetration performance of the cross protruding of pile tip is the strongest of different pile tip forms.The longer of pile shoe length is,the higher the penetration performance is,but when the length of the pile shoe is longer than 5 m,the penetration performance of the piles increases unobviously.The steel pile shoe and the PHC pile flange welded by slope plate can reduce the soil resistance during the pile driving,the set of the pile is larger and easier to penetrate to the design elevation.