DX桩承力盘破坏机理研究  

Research on the Mechanism of Failure of Bell Bearing of DX Pile

作　　者：朱春柏 彭文 ZHU Chun-bai;PENG Wen(Suzhou CRRC Construction Engrg.Co.,Ltd.,Suzhou 215126,China)

机构地区：[1]苏州中车建设工程有限公司,苏州215126

出　　处：《价值工程》2021年第26期74-77,共4页Value Engineering

摘　　要：由于施工工艺的限制,DX桩承力盘范围内没有配置钢筋,承力盘为素混凝土结构,因此,在进行DX桩设计时,必须对承力盘进行抗剪强度验算。根据现有混凝土结构设计规范中规定的公式计算出的结果偏于保守,当盘端阻力达到一定值时,承力盘先发生剪切破坏,因而,承载盘的存在对桩基竖向抗压承载力并没有大幅提升作用,但经过多次现场静载荷试验证明,DX桩相比于同直径、同桩长的普通直孔桩,其竖向抗压承载力会有明显提升,因此,承力盘发挥的作用是非常明显的。鉴于上述理论计算与工程实践的差异,本文通过理论分析方法对DX桩承力盘的受力机理进行了深入的分析,并采用FLAC3D有限差分软件对承力盘底面的土体反力分布形式进行了研究,可以发现DX桩承力盘范围内的应力分布与承力盘尖角密切相关,且承力盘底面的土体反力呈抛物线形式分布。Owing to the limitation of construction technology,bell bearing of DX pile has no steel reinforcements.Usually we need to check the shear strength of bell bearing of DX pile.The calculation results based on calculation formula on shearing strength of bell bearing defined in(Code for design of concrete structures)(GB 50010-2010)is conservative,bell bearing of DX pile is destructed by shearing stress,when the bell bearing resistance reaches a certain value,so the ultimate bearing capacity of DX pile can not be leaved a lot to be desired.According to in-situ loading test,the bearing capacity of DX pile has improved significantly than the general pile with the same diameter and length.In view of the difference between the theoretical calculation and engineering practice,this article conduct a deep analysis on the failure mechanism of bearing of DX pile,analyze the variation law of reaction force in soil under bell bearing via FLAC3D.We can see that the variation law of stress in bell bearing go hand in hand with the bell bearing angle,As well as,the reaction force in soil under the bell bearing distribute in the from of parabola.

关 键 词：DX桩 承力盘应力分布 理论计算 土体反力 

分 类 号：TU473.1[建筑科学—结构工程]