（安徽建筑大学土木工程学院， 合肥 230601）

［摘要］针对国内传统水泥土搅拌桩存在的缺陷，介绍了变径双向水泥土搅拌桩技术，并对其施工机械和施工工艺进行说明。为了验证变径双向水泥土搅拌桩的软土地基加固效果，通过现场试验和理论分析，分别就上部桩体扩径（钉形搅拌桩）和中部桩体扩径（中字形搅拌桩）这两种典型搅拌桩桩型的搅拌均匀性、桩身强度与承载力、路堤荷载下复合地基工作性状以及工程经济性等与试验段内的常规搅拌桩进行对比。试验结果表明，由于采用了变径和双向搅拌工艺，消除了溢浆现象，保证了桩身水泥掺入量，提高了桩身均匀性、强度及承载力；在路堤荷载作用下，采用变径搅拌桩可比常规搅拌桩节约近15%的水泥用量。

［关键词］钉形搅拌桩; 中字形搅拌桩; 常规搅拌桩; 施工工艺; 桩身强度; 桩承载力; 复合地基; 经济效益

中图分类号：TU472.3+6      文献标识码：A      文章编号：1002-848X(2014)08-0031-06

Technique and application research of diameter-varied bidirectional soil-cement deep mixing piles

Xi Peisheng, Liu Bo

 (School of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China)

Abstract: According to the existing shortcomings of traditional deep mixing pile techniques in China, diameter-varied bidirectional soil-cement deep mixing pile technique was introduced as well as the deep mixing machine and construction procedure. In order to investigate the improving effect for soft ground improvement, comparison tests were conducted between T-shaped pile, “zhong”-shaped pile and traditional pile through site tests and theoretical analysis. The comparisons included the homogeneity of the pile, pile strength, the bearing capacity of the pile, the performance of composite foundation under the embankment loads and the economic benefits analysis. The test results indicate that due to crafts of diameter variation and bidirectional mixing, grout spill phenomenon is eliminated effectively. The sufficient amount of cement in pile is ensured. And the homogeneity, strength and the bearing capacity of the pile are improved. Under the embankment loads, diameter-varied bidirectional soil-cement deep mixing pile can save about 15% cement compared to that of conventional one.

Keywords: T-shaped mixed pile; “zhong”-shaped mixed pile; traditional mixed pile; construction procedure; pile strength; bearing capacity; composite foundation; economic benefit

作者简介：席培胜，博士，副教授，高级工程师，Email：xipeisheng@163.com。

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