海中球状风化地层大直径超长钻孔桩施工技术  

Construction Techniques for Large Diameter and Very Long Bored Piles in Spheroidal Weathering Granite Layer in Sea

作　　者：李述宝[1] 赵鹍鹏[1] 

机构地区：[1]中铁大桥局集团第五工程有限公司,江西九江332001

出　　处：《桥梁建设》2011年第3期85-88,共4页Bridge Construction

摘　　要：厦漳跨海大桥北汊主桥为主跨780 m的半飘浮体系双塔双索面斜拉桥,其北桥塔基础位于球状风化花岗岩地层,采用36根2.5～3.0 m变直径钻孔桩,桩长74.5～111 m,钻孔深度达120.3 m。针对海洋地质环境下大直径超长钻孔桩易出现断钻、弯孔、沉碴超标、堵管、断桩等问题,采取逐桩地质超前钻、钻机选型、改进刀头形式与布置、增加配重及导向、选用较大规格钻杆、使用淡水泥浆、调整钻孔参数、控制导管埋深等技术,确保了钻孔桩的成桩质量。该桥主墩36根桩基经超声波检测均为Ⅰ类桩。The main bridge of the north bridge of Xiazhang Sea-Crossing Bridge is a semi-floating system cable-stayed bridge with double pylons,double cable planes and with a main span 780 m.The foundation of the north pylon of the bridge is located in the spheroidal weathering granite layer in sea and is made up of 36 nos.of 2.5～3.0 m bored piles of variable diameters.The length of the piles varies from 74.5 m to 111 m and the maximum boring depth accordingly reaches 120.3 m.In the light of a series of the problems,such as breaking of the boring stems,bending of the bored holes,excessive sediment of the boring slag,blockage of the concrete casting ducts and breaking of the piles,which were liable to occur in the construction of the large diameter and very long bored piles in the marine geology environment,the corresponding techniques,including those of boring each pile ahead of time,selecting the proper boring machines,improving the types and arrangement of cutting heads,adding the weight and pilot device,utilizing the large size boring stems and fresh water slurry,adjusting the boring parameters and controlling the embedding depth of the ducts,were applied.With these measures,the quality of the completed piles of the 36 bored piles has been guaranteed and through the ultrasonic inspection,all the piles are defined as Class I piles.

关 键 词：钻孔灌注桩 桩基础 施工技术 桥梁施工 

分 类 号：U443.15[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]