尖子山船闸上闸首软岩复合桩基受力特性

Mechanical characteristics of composite pile foundation in soft rock area at upper lock head of Jianzishan ship lock

为研究船闸分离式闸首复合桩基的受力特性,以尖子山船闸为依托,建立软岩上边墩复合桩基有限元模型,分析边墩位移、变形特征,提出桩顶力简化算法,研究软岩竖向力分担比ξV的影响因素。结果表明:边墩以刚体位移为主,检修期横向转动、竖轴扭转最大,桩基布置宜外密内疏;由于存在破碎带,ξV仅有11.5%;ξV近似与置换率呈双曲线关系、与软岩模量呈幂函数关系,桩间距越小,置换率越大,软岩模量越大,桩岩系数比越小,ξV越大。破碎带固结灌浆处理后,提高了桩基承载力,还使ξV有效提高到26.8%。

To study the mechanical characteristics of composite pile foundation at separated lock head,we establish a finite element model of composite pile foundation at separated lock head constructed on soft rock based on Jianzishan lock,analyze the deflections and deformations of the side piers,propose the simplification algorithm of pile top force,and research the influence factors of vertical load sharing ratio of soft rock ξV. The results show that the side pier is dominated by rigid body displacement,the lateral rotation and vertical axis torsion are the largest during the maintenance period,and the pile foundation layout should be dense outside and sparse inside.Because of the crushing zones, ξV is only 11. 5%. The relation between ξV and replacement ratio may be approximated by a hyperbola,and the relation between ξV and the soft modulus by a power function. The smaller the pile spacing is,the higher the displacement rate,the higher the soft modulus,the smaller the pile-rock coefficient ratio,the higher ξV is. The consolidation grout treatment of the crushing zone can help increase the bearing capacity of the pile and improve ξV to 26. 8% effectively.