大吨位挖孔灌注桩在黔中水利枢纽连续刚构渡槽中的应用

Application of large tonnage digging filling pile in continuous rigid frame aqueduct of Qianzhong Hydro-junction

为确保黔中水利枢纽一期工程4座高墩大跨连续刚构渡槽在施工及运行期的安全,采用大吨位挖孔混凝土灌注桩作为结构的基础。基于相似性原则,借鉴公路以及建筑行业桩基的建设经验,并结合结构自身受力特点,对渡槽工程大吨位挖孔灌注桩的结构进行设计;同时采用声波投射法和钻芯法对工程桩进行完整性检验,采用自平衡法对工程桩进行竖向抗压承载力检验。这4座连续刚构渡槽的桩基已于2012年12月全部完成施工,质量检验结果表明,桩基结构安全可靠,完全满足设计要求。

Large tonnage digging filling piles were used as structural foundation to ensure the integrity of four high-pier and long-span continuous rigid-frame aqueducts during the construction and the operating periods at the first stage of Qianzhong Hydro-junction project. Based on the similarity principle,the structure of large tonnage digging filling pile,referred to the pile construction experience of highway and building industry,and combined with its own loading features,was designed.At the same time,the integrity check and the vertical compressive bearing capacity test of engineering pile were accessed using crosshole sonic logging and core drilling method,and self-balanced method,respectively. The four pile foundations of continuous rigid frame aqueduct were completed in December 2012,and the pile quality tests showed that pile foundation structure was safe and reliable,which fully met the design requirements.