基于数值模拟和模型试验的公路桥梁摩擦桩有效桩长研究  

Study on Effective Length of Friction Pile of Highway Bridge Based on Numerical Simulation and Model Test

作　　者：黎景光 黄琛 陈通杰 LI Jing-guang;HUANG Chen;CHEN Tong-jie(Guangdong Nanyue Communications and Investment Co.,Ltd.,Guangzhou Guangdong 510100,China;Guangdong Nanyue Communications Heyuan-Huizhou-Dongguan Expressway Management Center,Guangzhou Guangdong 510100,China)

机构地区：[1]广东省南粤交通投资建设有限公司,广东广州510100 [2]广东省南粤交通河惠莞高速公路管理中心,广东广州510100

出　　处：《公路交通科技》2023年第3期150-157,共8页Journal of Highway and Transportation Research and Development

摘　　要：在桩基设计过程中,当桩数、桩径不能增加时,往往通过增加桩长来提高桩基承载力,但当桩长超过某定值时,其桩基承载力增长很小,此时桩长已达到有效桩长。为探讨桩基础有效桩长的计算方法,明确不同桩径的有效桩长合理范围,使桩基设计更为合理经济,以广东省某高速公路建造工程为依托,进行详细工程调研,确定了代表性土样。通过PLAXIS软件建立了不同桩径、不同桩长及不同土样下的桩基有限元模型,基于极限承载力控制法模拟计算了桩基有效桩长。根据几何相似与力学相似的原理设计室内模型试验,以不同桩径、不同桩长为变量,共制作了18根缩尺模型桩,讨论了桩基极限承载力与桩径桩长的发展规律及分析桩基有效桩长。结合荷载-沉降理论曲线确定法对不同桩径模型桩进行了计算分析,进一步验证了试验及数值模拟的正确性及有效性。结果表明:当桩径和地质条件不变时,桩基承载力与桩长呈正相关;随着桩长的增加,极限承载力的增速变缓,后期承载力的增长大大小于前期承载力的增长;当桩长超过一定值后,桩基的承载力几乎不变化,且3种土质类别对有效桩长的影响不明显;针对试验所用3类土体,基桩的有效桩长可取46d~50d(d为基桩直径)。In the process of pile foundation design,the bearing capacity of the pile foundation is often increased by increasing the pile length when the number and diameter of piles cannot be increased.However,when the pile length is beyond a certain value,the bearing capacity of the pile foundation increases very little,and the pile length has reached the effective pile length.In order to explore the calculation method of effective pile length of pile foundation and clarify the reasonable range of effective pile lengths of different pile diameters,and making the pile foundation design more reasonable and economic,relying on an expressway construction project in Guangdong Province,the detailed engineering investigation is carried out to determine representative soil samples.The finite element models of pile foundation with different pile diameters,pile lengths and soil samples are established by PLAXIS software,and the effective pile lengths of pile foundation are simulated by using the ultimate bearing capacity control method.According to the principle of geometric similarity and mechanical similarity,the indoor model test is designed.A total of 18 scaled model piles are made with different pile diameters and pile lengths as variables.The development rule of the ultimate bearing capacity of the pile foundation with the pile diameter and pile length is discussed,and the effective pile length of the pile foundation is analyzed.The model piles with different pile diameters are calculated and analyzed by using the load-settlement theoretical curve determination method,and the correctness and effectiveness of the test and numerical simulation are further verified.The result shows that(1)when the pile diameter and geological condition remain unchanged,the bearing capacity of the pile foundation is positively correlated with the pile length;(2)with the increase of pile length,the growth rate of ultimate bearing capacity slows down,and the growth of bearing capacity in the later stage is much less than that in the earlier stage;(

关 键 词：桥梁工程 有效桩长 模型试验 摩擦桩 桩基承载力 

分 类 号：U448.23[建筑科学—桥梁与隧道工程] X913.4[交通运输工程—道路与铁道工程]