鄂东长江公路大桥北主塔墩超长嵌岩桩施工  

Construction of Very Long Rock Socketed Piles for North Pylon Pier of Edong Changjiang River Highway Bridge

作　　者：霰建平[1] 高安荣[1] 张建军[1] 张峰[1] 周敏[1] 

机构地区：[1]中交第二公路工程局有限公司,陕西西安710065

出　　处：《桥梁建设》2009年第4期69-71,共3页Bridge Construction

摘　　要：鄂东长江公路大桥北主塔墩采用群桩基础，共设33根在覆盖层内直径2．8m、基岩内直径2．5m的钻孔灌注桩，桩长71m，入岩深度38～44m，地质条件复杂。采用KP3500及金泰GW-35钻机进行钻孔灌注桩施工，钻孔泥浆采用优质PHP膨润土泥浆。钻进成孔主要分护筒内钻进、护筒以下覆盖层钻进和基岩内钻进3个阶段。采用2次清孔工艺，确保沉渣厚度达到设计要求。钢筋笼按照12m标准节段分6节利用长线法同槽加工成型，采用动臂吊机起吊和就位。钻孔桩水下混凝土由拌和站集中拌制，混凝土搅拌运输车运送到墩位混凝土卧泵旁采用刚性导管法泵送浇注。The foundation for the north pylon pier of Edong Changjiang River Highway Bridge is composed of group piles. Totally 33 numbers of the bored piles, each 2.8 m in diameter in the overburden stratum and 2.5 m in diameter in the rock, are used. The length of a pile is 71 m and the depth of the piles socketed in the rock is 38-44 m. The ground conditions at the location of the foundation are complicated. In the construction of the piles, the KP3500 and Jintai GW-35 boring machines were used and the slurry for protecting the bored holes was the high quality PHP bentonite slurry. The boring of the holes was carried out in three stages in the steel casings, in the overburden stratum under the casings and in the rock further under the stratum. A bored hole was cleared off two times to ensure that the thickness of the deposited slag can meet the design requirements. A reinforcement cage was made in six sections in the same die by the long line method acciording to a standard section length of 12 m and was set in place by the jib crane. The tremie concrete for the bored piles was produced at a central batching plant and was delivered by agitating truck to the pier site where the concrete was then pumped into the bored holes through the rigid ducts.

关 键 词：桥梁基础 深水基础 钻孔灌注桩 超长桩 嵌岩桩 施工 

分 类 号：U445.551[建筑科学—桥梁与隧道工程]