劲性复合桩外界面侧阻强化效应试验研究  

Experiment on the outer interface enhanced shaft-resistance effect of the stiffened deep-cement-mixing pile

作　　者：包华 洪俊青 夏胞刚 姚振宇 Bao Hua;Hong Junqing;Xia Baogang;Yao Zhenyu(School of Transportation and Civil Engineering,Nantong University,Nantong 226019,China;Jiangsu Jinzhuang Geotechnical Technology Co.Ltd,Nantong 226009,China)

机构地区：[1]南通大学交通与土木工程学院,江苏南通226019 [2]江苏劲桩岩土科技有限公司,江苏南通226009

出　　处：《建筑科学》2022年第1期107-113,共7页Building Science

基　　金：2020年江苏省产学研合作项目(BY2020176)。

摘　　要：劲性复合桩通常是由钢筋混凝土芯桩和外包水泥土组成的组合构件,其具有双重界面,即由"芯桩"与"水泥土"构成的内界面以及由"水泥土"与"桩周土"构成的外界面。试验研究表明:劲性复合桩具有摩擦型桩和大直径桩的特性;同比条件下,其竖向承载力比钻孔灌注桩提高62%~76%,其外界面总侧阻力比钻孔灌注桩提高73%~91%;外界面总侧阻力占总承载力比例81.9%~83.3%,静载试验Q-s曲线大多呈现为缓降曲线。研究表明:水泥土的重组固化效应和扩散层效应是劲性复合桩外界面具有优异力学性能的主要原因。建议劲性复合桩外界面土层侧阻力综合调整系数取值宜为1.8±0.1。Stiffened deep-cement-mixing pile(SDCMP)is a type of composite member,which consists of the reinforced core pile and the outer cement soil usually.SDCMP contains dual interfaces:the inner interface that is the core pile-cement soil interface,and the outer interface that is the cement soil-peripheral soil interface.The experiments show that SDCMP possesses the properties of the friction pile and the large diameter pile.On the same conditions,the vertical bearing capacity of the SDCMP is 62%~76%higher than the bored cast-in-place pile(BCPP),the shaft resistance(SR)of the SDCMP is increased by 73%~91%than the BCPP.The SR of the outer interface accounts for 81.9%~83.3%of the total bearing capacity.Most of the static-loading Q-s curves descend slowly generally.The research presents that the excellent mechanic performance of the outer interface essentially is derived by restructuring the curing effect and the diffusion layer effect of the cement soil.The generalized adjusting factor on the SDCMP outer-interface SR is suggested to be 1.8±0.1.

关 键 词：劲性复合桩 外界面 侧阻力 综合调整系数 

分 类 号：TU443[建筑科学—岩土工程]