珊瑚礁灰岩地层灌注桩侧摩阻力特征及发挥系数取值研究与应用  

Research and application of lateral friction resistance characteristics and coefficient value of cast-in-place piles in coral reef limestone strata

作　　者：张永涛 刘玉擎[1] 陈培帅[2] 罗会武[2] 邓志强[2] 喻成成 ZHANG Yongtao;LIU Yuqing;CHEN Peishuai;LUO Huiwu;DENG Zhiqiang;YU Chengcheng(School of Civil Engineering,Tongji University,Shanghai 200092,China;CCCC Second Harbour Engineering Company Ltd.,Wuhan,Hubei 430040,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]中交第二航务工程局有限公司,湖北武汉430040

出　　处：《岩石力学与工程学报》2023年第3期748-757,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：湖北省科技厅高端外国专家项目(2021EJD012);中国交通建设股份有限公司科技研发项目(2018ZJKJPTJS02)。

摘　　要：为了探究界面形态及界面胶结状态对珊瑚礁灰岩–灌注桩侧阻发挥系数的影响,以援马尔代夫中马友谊大桥区域的礁灰岩为研究对象,利用大型直剪仪开展礁灰岩–混凝土界面剪切试验,研究完整岩体状态的珊瑚礁灰岩–混凝土界面强度发挥机制,结合现场自平衡试桩试验,研究破碎及较破碎岩体状态的珊瑚礁灰岩层–灌注桩侧阻发挥系数。结果表明:(1)当礁灰岩与混凝土界面无填充或泥皮填充时界面破坏为滑动摩擦,当混凝土直接浇筑在礁灰岩上面时,界面破坏受控于礁灰岩内部缺陷;(2)礁灰岩与灌注桩无胶结时,锯齿界面的抗剪强度均高于直桩界面,约77%;(3)礁灰岩与灌注桩胶结时,由于水泥浆的扩散、填充作用,礁灰岩–混凝土界面形成了界面增强体,界面强度发挥受控于礁灰岩内部缺陷,界面形态对界面剪切强度无明显提升作用;(4)结合现场自平衡试桩试验,确定了清水成孔工艺破碎岩体的礁灰岩层灌注桩嵌岩段桩侧摩阻力发挥系数为0.053~0.108,高于陆源岩石2倍以上。以上成果揭示了珊瑚礁灰岩层灌注桩侧阻发挥机制,论证了清水成孔工艺灌注桩能充分发挥礁灰岩地层承载性能,可为岛礁大型工程基建的设计及施工提供参考。In order to explore the influence of interface form and filling state on the lateral friction resistance play coefficient of reef limestone-cast-in-place piles,the reef limestone in the area of China-Malaysia Friendship Bridge was used as the research object,and the reef limestone-concrete interface shear test was carried out with a large direct shear instrument to study the strength play mechanism of coral reef limestone-concrete interface in the intact rock state,and the lateral resistance play factor of coral reef limestone layer-cast-in-place pile in the fractured and more fractured rock state was studied in combination with the field self-balancing pile test.The results show that:(1)when the interface between reef limestone and concrete is not filled or filled with mud skin,the interface damage is sliding friction,and when concrete is poured directly with reef limestone,the interface damage is controlled by the internal defects of reef limestone;(2)When the reef limestone and the cast-in-place pile are not cemented,the shear strength of the saw tooth interface is higher than that of the straight pile interface,about 77%;(3)When the reef limestone is cemented with the cast-in-place pile,due to the diffusion and filling of the cement slurry,the reef limestone-concrete interface forms an interface reinforcement.The failure surface of reef limestone-concrete specimens is controlled by the internal defects of the reef limestone.The interface form does not significantly improve the shear strength of the interface;(4)Combined with the field self-balancing test pile test,it is determined that the coefficient of lateral friction resistance of the rock-socketed section of the rock-socketed pile in the reef limestone stratum with the broken rock of clear water pore-forming process is 0.053–0.108,which is more than 2times higher than that of the land source rock.The above results demonstrate that the clear-water pore-forming castin-place pile can give full play to the bearing performance of reef limestone strata,and c

关 键 词：桩基础 礁灰岩 灌注桩 界面剪切 桩侧摩阻力发挥系数 自平衡试桩法 

分 类 号：TU47[建筑科学—结构工程]