扩底钻孔灌注桩扩底局部夹泥的成因分析与预防

Bored Piles of Local Causes Analysis and Prevention of Mud

扩底钻孔灌注桩施工工艺在国内从90年代发展至今已非常成熟,从考虑经济及工期节约的角度上经常会设计大直径扩底钻孔灌注桩。但扩底钻孔灌注桩往往因岩层、桩深、桩径、地下水和机械施工情况等的影响下出现扩底部分或严重夹泥而导致扩底失效,影响因素主要有扩底段岩层性质、扩底钻头形状、泥浆护壁及清孔情况、钢筋笼及导管吊装。

The technology of bored piles construction has been developed in China from 90s. The large diameter bored cast-in-situ concrete piles are often designed because of considering economic and saving time. But bored piles, the depth of pile and pile diameter, often because of strata under the influence of groundwater, construction machinery, such as the expansion of bottom part or serious mud and cause of the failure, the main causes are the following four： enlarge the bottom section of rock properties, expanded bore bit shape, slurry and hole cleaning and protecting, reinforcing cage and catheter hoisting.