(河南理工大学土木工程学院， 焦作 454000)

［摘要］对高喷插芯组合桩（JPP桩）的四种常用组合形式进行了模型试验研究，通过在芯桩上粘贴应变片和在桩底埋设土压力盒等仪器对JPP桩轴力、桩侧摩阻力及桩端阻力进行了测量，得到如下结论：水泥土与芯桩的不同组合形式对JPP桩承载力有较大影响；水泥土分段后，形成类似葫芦状的表面，增大了桩与桩周土的粗糙度，并且每段水泥土端部均能提供一定的端阻力，桩承载力提高明显；组合段位置对桩承载力也有较大影响，水泥土与芯桩下部组合时桩侧摩阻力增大明显，下组合的JPP桩承载力表现出比分段组合1的JPP桩承载力大的特点，组合段宜设计在JPP桩下部；工程设计中，JPP桩宜采用3段以上的分段组合形式，并将分段组合放在芯桩的中下部，根据土层性质分段高压旋喷水泥土，从而达到节约造价、提高桩承载力的目的。

［关键词］高喷插芯组合桩; 组合优化; 承载性能; 荷载传递; 模型试验

中图分类号：TU470      文献标识码：A        文章编号：1002-848X(2014)08-0015-06

Experimental research on combination optimization and bearing mechanism of jet grouting soil-cement-pile strengthened piles

Ren Lianwei, Li Guo, Dun Zhilin, Yang Quanwei

 (School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454000, China)

Abstract: Model test was carried out for four kinds of combinations of jet grouting soil-cement-pile strengthened piles (JPP pile). Axial force, shaft resistance and pile-top resistance were measured by strain gages pasted on core pile and earth pressure cells buried in pile bottom, and the following conclusions were obtained that different combinations forms of cement-soil and core pile have great impact on bearing capacity of JPP pile. The gourd-shaped similar surface caused by the cement-soil segment increases interface roughness between the JPP pile and soil, and each cement-soil top can provide some top resistance, which improves bearing capacity significantly. Segment locations have great impact on the bearing capacity of JPP pile. Shaft resistance increases significantly under cement-soil combination with the lower core pile. Bearing capacity of lower combined JPP pile is larger than segment-1 JPP pile, so combined segment should be set in the lower part of JPP pile in engineer design. In the engineering design, JPP pile should adopt three sub-combinations above. Combined segment should be placed in the lower of core pile, and jet grouting cement-soil should be segmented according to soil characteristics, so as to save cost and improve bearing capacity.

Keywords: jet grouting soil-cement-pile strengthened pile; combination optimization; bearing mechanism; load transfer; model test

*河南省重点攻关项目（122102210119），国家自然科学基金项目（41102169）。

作者简介：任连伟，博士，副教授,Email:renhpu@163.com。

参考文献

［1］王健, 夏明耀, 傅德鸣. H型钢与水泥土搅拌桩维护结构的设计与计算［J］. 同济大学学报：自然科学版, 1998, 26(6): 636-639.

［2］刘金砺, 刘金波. 水下干作业复合灌注桩试验研究［J］. 岩土工程学报, 2001, 23(5): 536-539.

［3］凌光容, 安海玉, 谢岱宗, 等. 劲性搅拌桩的试验研究［J］. 建筑结构学报, 2001, 22(2): 92-96.

［4］任连伟, 刘汉龙, 雷玉华. 高喷插芯组合桩技术及其应用［J］. 岩土工程学报, 2008, 30(S1): 518-522.

［5］刘汉龙, 谭慧明, 彭劼, 等. 大型桩基模型试验系统的开发［J］. 岩土工程学报, 2009, 31(3): 452-457.

［6］MAKOTO KIYOSUMI, OSAMU KUSAKABE, MASATOSHI OHUCHI. Model tests and analyses of bearing capacity of strip footing on stiff ground with voids［J］. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2011, 137(4): 363-375.

［7］徐文希, 张敏, 朱怡, 等. 钻孔灌注桩抗压承载力试验方法的对比分析［J］. 建筑结构, 2013, 43(20): 96-99.

［8］梁发云, 廖晨聪, 毛磊, 等. 竖向-水平荷载联合作用下单桩性状模型试验研究［J］. 建筑结构, 2013, 43(6): 92-94,98.