红莲大桥双斜塔主桥全套筒全回转钻孔桩施工分析

Construction Analysis of Full Sleeve and Full Rotary Drilled Pile for Main Bridge ofDouble Inclined Tower of Honglian Bridge

为探讨全套筒全回转钻孔桩施工技术,以红莲大桥双斜塔主桥为例,立足施工的重难点,详细分析了全套筒全回转钻孔桩施工技术的应用要点及施工效果。实践得出,红莲大桥地质条件特殊,传统钻孔灌注桩施工难以在不良地质条件下完成桥梁桩基础施工任务。采用全套筒全回转钻孔桩施工技术,以双壁钢套管作为支撑,能够承受较大管壁沙层的阻力,并可以将扭矩传递给下部切削刀刃,用于切削坚硬的岩石,从而起到全过程护壁的作用。即便不使用护壁浆液,也可以防止塌孔、缩颈等问题的发生,从而保证桩基施工顺利完成。

In order to discuss the construction of full sleeved and full rotary bored pile,based on the actual case of the main bridge of double inclined tower of Honglian Bridge,the application points and construction effects of full sleeved and full rotary bored pile construction technology are analyzed in detail,focusing on the construction difficulties.The practice shows that due to the special geological condition of Honglian Bridge,the traditional bored pile construction is difficult to construct the bridge pile foundation under the bad geological condition.The construction technology of full sleeve and full rotary drilled pile is supported by double-wall steel casing,which can withstand the resistance of large sand layer of pipe wall,and transmit the torque to lower cutting edge to cut hard rocks,so as to conduct wall protection in whole process.Even if the wall slurry is not used,it can prevent the occurrence of hole collapse and neck shrinkage,so as to ensure the smooth completion of pile foundation construction.