双向搅拌粉喷桩技术开发与应用研究  

Technical development on bidirectional dry jet mixing columns and its engineering application

作　　者：谢胜华[1,2] 刘松玉[1] 杜广印[1] 刘志彬[1] 

机构地区：[1]东南大学岩土工程研究所,南京210096 [2]安徽工业大学建筑工程学院,安徽马鞍山243002

出　　处：《工程勘察》2011年第8期7-11,37,共6页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金项目(50879011);江苏省交通科技项目(08Y33)

摘　　要：常规粉喷桩(单向搅拌)加固海相软土地基普遍存在着水泥土搅拌不均匀、桩身不连续、桩身强度低等问题,且施工过程中容易出现"沉桩"现象。针对上述问题,对常规粉喷桩机钻头进行改进,将螺旋式变成三层六片叶片;同时增加内钻杆和上置滑动式动力设备,实现"双杆双向"搅拌。依托现场试验段工程,详细介绍了双向搅拌粉喷桩的成桩机械和施工工艺。成桩结束后进行取芯检测并进行标准贯入试验和无侧限抗压强度试验,并在填筑期进行沉降监测,结果表明:双向搅拌粉喷桩较常规粉喷桩具有桩身搅拌均匀、成桩质量好、桩身强度高等优点,其单桩承载力较常规粉喷桩有很大提高,且工后沉降小,经济效益显著,具有较好的应用推广前景。The problems such as the unevenly mixing of soil cement,the discontinuous column body,the low strength body mass and the crater phenomenon during the construction of the commonly-used dry jet mixing（DJM） columns are usually met with in the marine soil improvement.The conventional DJM equipment is modified.The drill bit is changed from the spiral type into three-layer six blades.In addition,an inner drill rod and the upper-mounted sliding power equipment are also added.The construction technique with the double pipes and the bidirectional mixing is successfully developed.Based on the full scale field tests,the double mixing DJM column mechanical and the construction technique are introduced,combined with the field inspection of the column filling quality and the construction monitoring of the settlement.It is showed that the bidirectional mixing DJM columns yield the high improvement in the mixing effect which results in more homogenous columns with good quality and high strength than by the conventional DJM columns,and the bearing capacity of the single column is greatly improved compared with that from the conventional DJM column.The bidirectional mixing DJM columns are of the low settlement after construction and the significant economic benefits,which would be provided with a good application prospect compared to the conventional DJM columns.

关 键 词：双向搅拌粉喷桩 施工工艺 质量评价 加固效果 

分 类 号：TU472.3[建筑科学—结构工程]