直径850 mm振动沉管灌注桩沉桩过程数值模拟研究  

Research on Numerical Simulation of Driving Process of 850 mm Diameter Vibro Driven Cast-in-Place Pile

作　　者：马岷成 王跃军 郑亚林 巩立斌 MA Mincheng;WANG Yuejun;ZHENG Yalin;GONG Libin(Gansu Construction and Design Consulting Group Co.,Ltd.,Lanzhou 730050,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]甘肃省建设设计咨询集团有限公司,甘肃兰州730050 [2]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《甘肃科学学报》2022年第3期112-118,共7页Journal of Gansu Sciences

摘　　要：振动沉管灌注桩由于其承载能力高\,沉降量低等诸多优点被广泛应用于各类建筑工程,目前已经投入使用的振动沉管灌注桩最大直径是600 mm,基于天水客机改装货机项目中所采用的最大桩径为850 mm的振动沉管灌注桩现场施工进行实例分析。采用数值模拟的方法,通过建立三维有限元模型,模拟振动沉管灌注桩沉桩过程,得到了沉桩时桩侧土体的应力场、位移场和沉桩阻力的变化规律,通过加载和渗流条件下模拟黄土的湿陷过程,预测湿陷量。结果表明,桩体下沉是因为土体的剪切破坏而使得桩体贯入,在沉桩的过程中,桩侧土体的应力值不断增大,且桩端附近土体应力值明显大于其余处土体的应力值;通过桩顶设置位移值可以近似模拟沉桩过程并容易收敛,模拟值与实际值近似;沉桩阻力曲线近似为双折线。黄土湿陷性模拟结果表明,沉降过程中土体区域的水平位移较小,以竖向位移为主,离桩近的位置土体沉降较小,说明采用灌注桩对湿陷性黄土的沉降具有抑制作用。数值模拟结果可为大直径桩的施工提供一定的指导。At present,the vibro driven cast-in-place pile is widely used in all kinds of construction projects because of its good bearing capacity,high settlement and many other advantages.The largest diameter of vibro driven cast-in-place pile has been put into use is 600 mm.Based on the field construction example analysis of the vibro driven cast-in-place pile with the largest diameter of 850mm used in the cargo aircraft project refitted from Tianshui airliner,by using the method of numerical simulation,a three-dimensional finite element model is established to simulate the process of vibro driven cast-in-place pile.The variation laws of stress field,displacement field and pile driving resistance are obtained.The collapsibility process of loess is simulated under loading and seepage conditions,and the collapsibility is predicted.The results show that the pile sinking is triggered by the shear failure of the soil,which makes the pile penetration.In the process of pile sinking,the stress value of the soil on the side of the pile increases continuously,and the stress value of the soil near the pile end is significantly greater than that of the rest of the soil.The displacement value at the pile top can approximately simulate the pile sinking process and is easy to converge,and the simulated value is similar to the actual value;the pile sinking resistance curve is approximately the same.The results of loess collapsibility simulation show that the horizontal displacement is small,the vertical displacement is dominant,and the soil settlement near the pile is small,which indicates that the cast-in-place pile can inhibit the settlement of collapsible loess.The numerical simulation results could provide some guidance for the construction of large diameter piles in the future.

关 键 词：大直径振动沉管灌注桩 挤土效应 数值模拟 施工流程 

分 类 号：TU443[建筑科学—岩土工程]