振动锤下钢护筒气举反循环清孔旋挖钻孔施工技术

以江西省九江地区的德安集贸市场桩基工程为例，介绍了振动锤下钢护筒配套气举反循环清孔旋挖钻孔灌注桩施工技术应用情况及成桩关键技术措施。旋挖钻机在桩基工程施工中的成孔效率高，但在松散地层及容易坍塌地层中施工存在沉渣控制较为困难的问题，因此解决好该工程沉渣满足设计要求，是项目成功的关键所在。实践证明，采用振动锤下钢护筒隔离松散地层和容易坍塌地层以及气举反循环清孔相结合的措施，可彻底解决孔底沉渣过大的问题。

Rotary drilling with air-lifting reverse circulation for hole cleaning and vibration hammer for setting of steel casing

Taking the pile foundation project of the Dean market in Jiujiang area of Jiangxi Province as an example, this paper introduces the application and key technical measures of rotary drilled cast-in-place piles with air-lift reverse circulation hole cleaning and the vibration hammer for setting steel casing. The rotary drilling rig has a high efficiency in the construction of pile foundation, but control of settlements is difficult in the loose and collapsible stratums; therefore, it is the key to the success of the project to solve the problem with the settlements. Practice has proved that the combination of the vibrating hammer for setting casing to protect collapsible formation with the air lifting reverse circulation for cleaning can completely solve the problem of excessive settlements at the bottom of the hole.