大直径后压浆灌注桩承载力和沉降的实用计算方法研究  

A practical method of calculation of bearing capacity and settlement of large-diameter post-grouting piles

作　　者：万志辉[1,2] 戴国亮[1,2] 高鲁超 龚维明[1,2] WAN Zhi-hui;DAI Guo-liang;GAO Lu-chao;GONG Wei-ming(Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education,Southeast University,Nanjing,Jiangsu 211189,China;School of Civil Engineering,Southeast University,Nanjing,Jiangsu 211189,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京211189 [2]东南大学土木工程学院,江苏南京211189

出　　处：《岩土力学》2020年第8期2746-2755,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51678145,No.51878160);国家重点研发计划专项(No.2017YFC0703408);江苏省六大人才高峰项目(No.XNY-047)。

摘　　要：基于收集的139个工程中的716根试桩静载试验数据,对大直径后压浆桩承载力和沉降的实用计算方法进行研究,在统计分析的基础上给出了以土层为分类的侧摩阻力及端阻力增强系数,建立了适用于不同压浆类型的大直径后压浆桩承载力实用计算方法,并且通过大量的实测数据验证了该方法的可靠性。为了考虑后压浆对大直径桩基础沉降控制的影响,在未经压浆的大直径桩基础沉降计算方法的基础上引入了后压浆沉降影响系数,基于统计分析给出了后压浆沉降影响系数的建议取值范围,提出了一种适用于不同土层的大直径后压浆桩沉降计算经验预估方法,最后通过工程实例验证了该方法的适用性。该研究成果纳入了中华人民共和国行业标准《公路桥涵地基与基础设计规范》(JTJ3363-2019)及工程建设行业标准《公路桥梁灌注桩后压浆技术规程》(T/CECS G:D67-01-2018),可为后压浆技术的广泛应用起到推动作用。Based on the static load test data of 716 test piles collected from 139 projects,the practical calculation method of bearing capacity and settlement of large-diameter post-grouted piles was studied.The improvement coefficients of the side friction and base resistance of soil layer were given primarily based on statistics analysis,and the practical calculation approach for the bearing capacity of large-diameter post-grouted piles applicable to different grouting types was presented.The reliability of the proposed approach was verified by a large number of measured data.Moreover,the influence coefficient of post-grouting settlement was introduced based on the settlement calculation method of large-diameter pile foundation without grouting.Based on the statistical analysis,the recommended range of influence coefficient of post-grouting settlement was given,and an empirical estimation method for calculating settlement of large-diameter post-grouted piles suitable for different soil layers was proposed.Finally,the applicability of the proposed method was verified using engineering examples.The research results have been incorporated into the industry standard of the People’s Republic of China Code for design of ground base and foundation of highway bridges and culverts(JTJ 3363-2019)and the industry standard of national project construction Technical specification for post-grouting of cast-in-place pile of highway bridges(T/CECS G:D67-01-2018),which can promote the wide application of post-grouting technique.

关 键 词：大直径后压浆桩 竖向承载力 增强系数 统计分析 沉降计算 后压浆沉降影响系数 

分 类 号：TU473[建筑科学—结构工程]