挤压破碎倾斜板岩大直径深水钻孔桩施工技术  

Construction Techniques for Large Diameter Deep-Water Bored Piles in Compresso-Crushed Oblique Slate Zone

作　　者：邓敬雄[1] 

机构地区：[1]中铁大桥局集团有限公司,湖北武汉430050

出　　处：《世界桥梁》2015年第2期21-24,共4页World Bridges

摘　　要：蒙西华中铁路洞庭湖特大桥主桥采用（98＋140＋406＋406＋140＋98）m三塔双索面钢箱钢桁结合梁斜拉桥,桥塔墩采用22根3.0m钻孔桩基础。桥址处覆盖层较浅,其下为挤压破碎倾斜岩面,施工过程中极易出现塌孔、埋钻、斜孔。钻孔灌注桩施工过程中,首先采用履带式跟管钻机钻进,压缩空气吹渣成孔,在直径3.2~3.5m的圆周上均匀布置10个注浆孔,采取袖阀花管分层注浆预加固;然后采用优质泥浆护壁,利用3000型和4000型钻机钻进,钻进过程中针对不同的地层调整钻压、钻速、泥浆比重以及增加稳定器等措施,确保顺利成孔。实践表明,该桥通过采取桩周注浆预加固、优质泥浆护壁、增加稳定器等技术措施顺利完成了3号、4号、5号桥塔墩共66根钻孔灌注桩施工,桩检均为Ⅰ类桩。The main bridge of Dongting Lake Bridge on Western Inner Mongolia to Central China Railway is a three-pylon steel box and steel truss composite girder cable-stayed bridge with span arrangement of（98＋140＋406＋406＋140＋98）m and with double cable planes.The pylon piers are supported on the foundations formed of 22 no.3.0 m bored piles.The overlay at the bridge site is shallow,beneath which are the compresso-crushed oblique slates that make the bored pile construction susceptible to incidents of hole collapse,drill burying and hole inclination.During the construction of the bored piles,the crawler drills were first used to drill downwards,and then compressed air were ingected to blow the slurry for hole formation.10 tremie concrete injection holes were opened uniformly around the 3.2~3.5 m diameter circumference and the holes were pre-strengthened by layered concrete injected via the sleeve-valve tubes.And then the high-quality slurry walls were used for support.The 3000 type and 4000 type drills were used for drilling.During the drilling process,a series of measures were taken,including adjusting the drilling pressure,drilling speed and slurry gravity and adding stabilizers according to different stratum,so as to ensure the smooth formation of holes.The engineering practice proves that by pre-strengthening the piles via injecting tremie concrete around the pile circumference,adopting high-quality slurry supporting wall and adding stabilizers,the construction of a total of 66 bored piles for the No.3,No.4and No.5pylon piers were smoothly completed,and all the piles were identified as gradeⅠ piles.

关 键 词：桥梁基础 挤压破碎带 倾斜岩面 深水 大直径钻孔灌注桩 注浆预加固 优质泥浆 桥梁施工 

分 类 号：U445.551[建筑科学—桥梁与隧道工程]