INFLUENCE OF DIFFERENT PILE LENGTHS ON RIGID GRID-PILE REINFORCED SUBGRADE WITHOUT BEARING STRATUM PENETRATION
MO Haihong1，HUANG Wenfeng1，2，FANG Yingguang1
(1. School of Civil Engineering and Transportation，South China University of Technology，Guangzhou，Guangdong 510640，
China；2. South Branch of Northeast Electric Power Design Institute of China Power Engineering Consulting Group，
Guangzhou，Guangdong 510655，China)
Abstract：According to weak regions of rigid pile composite foundation and piled embankments with bearing stratum penetration，the reinforcement of weak regions by using stretching net，rigid grid and additional pile of rigid gird-pile composite foundation was analyzed. The changing characteristics of force and deformation of rigid grid-pile composite foundation with and without bearing stratum penetration were investigated under different pile lengths；and the feasibility whether the rigid grid-pile composite foundation is applicable to the case without bearing stratum penetration was evaluated. The results show that，without bearing stratum penetration，the bending moment and shear force of most side piles are large，and their distribution regions would increase along the direction of embankment center when the pile length decreases. When the pile length increases，the load ratio of most piles increases，and the bending moment and shear force of side pile，embankment settlement and vertical deformation outside the embankment decrease. By increasing the pile length，applying PTC pile to enlarging the cross-section of central pile，and decreasing the additional pile?s diameter，the rigid grid-pile composite foundation can be optimized and be applicable to the case of bearing stratum penetration.
[1] 何 宁，娄 炎. 路堤下刚性桩复合地基的设计计算方法研究[J]. 岩土工程学报，2011，33(5)：797–802.(HE Ning，LOU Yan. Design and calculation method for rigid pile composite foundation under embankments[J]. Chinese Journal of Geotechnical Engineering，2011，33(5)：797–802.(in Chinese))
[2] 宋二祥，武思宇，刘华北. 刚性桩复合地基地震反应的拟静力计算方法[J]. 岩土工程学报，2009，31(11)：1 723–1 728.(SONG Erxiang，WU Siyu，LIU Huabei. Quasi-static calculation method for seismic response of rigid pile composite foundation[J]. Chinese Journal of Geotechnical Engineering，2009，31(11)：1 723–1 728.(in Chinese))
[3] 曹卫平，陈云敏，陈仁朋. 考虑路堤填筑过程与地基土固结相耦合的桩承式路堤土拱效应分析[J]. 岩石力学与工程学报，2008，27(8)：1 610–1 617.(CAO Weiping，CHEN Yunmin，CHEN Renpeng. Analysis of soil arching in piled embankments considering coupled effect of embankment filling and soil consolidation[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(8)：1 610–1 617.(in Chinese))
[4] ZHUANG Y，ELLIS E A，YU H S. Plane strain FE analysis of arching in a piled embankment[J]. Proceedings of the ICE—Ground Improvement，2010，163(4)：207–215.
[5] VAN EEKELEN S J M，BEZUIJEN A，VAN TOL A F. Analysis and modification of the British Standard BS8006 for the design of piled embankments[J]. Geotextiles and Geomembranes，2011，29(3)：345–359.
[6] KOUSIK D. A mathematical model to study the soil arching effect in stone column-supported embankment resting on soft foundation soil[J]. Applied Mathematical Modelling，2010，34(12)：3 871–3 883.
[7] 娄 炎，何 宁，娄 斌. 长短桩复合地基中的土拱效应及分析[J]. 岩土工程学报，2011，33(1)：77–80.(LOU Yan，HE Ning，LOU Bin. Analysis of soil arching of composite foundations with long and short piles[J]. Chinese Journal of Geotechnical Engineering，2011，33(1)：77–80.(in Chinese))
[8] ZHENG G，JIANG Y，HAN J，et al. Performance of cement-fly ash- gravel pile-supported high-speed railway embankments over soft marine clay[J]. Marine Georesources and Geotechnology，2011，29(2)：145–161.
[9] 龚晓南. 广义复合地基理论及工程应用[J]. 岩土工程学报，2007，29(1)：1–13.(GONG Xiaonan. Generalized composite foundation theory and engineering application[J]. Chinese Journal of Geotechnical Engineering，2007，29(1)：1–13.(in Chinese))
[10] 张忠苗，喻 君，张广兴. 根据不同桩长对比试验优化设计桩持力层的研究[J]. 岩石力学与工程学报，2007，26(增2)：4 251–4 257. (ZHANG Zhongmiao，YU Jun，ZHANG Guangxing. Study on optimization design of pile bearing layer according to contrastive tests with different pile lengths[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(Supp.2)：4 251–4 257.(in Chinese))
[11] 徐正中，陈仁朋，陈云敏. 软土层未打穿的桩承式路堤现场实测研究[J]. 岩石力学与工程学报，2009，28(11)：2 336–2 341.(XU Zhengzhong，CHEN Renpeng，CHEN Yunmin. Study of in-situ data of pile-supported embankment with pile partially penetrated in soft soils[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(11)：2 336–2 341.(in Chinese))
[12] 杨光华，李德吉，官大庶. 刚性桩复合地基优化设计[J]. 岩石力学与工程学报，2011，30(4)：818–825.(YANG Guanghua，LI Deji，GUAN Dashu. Optimization design of rigid pile composite foundation[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(4)：818–825.(in Chinese))
[13] 中华人民共和国行业标准编写组. JGJ 94—2008建筑桩基技术规范[S]. 北京：中国建筑工业出版社，2008.(The Professional Standards Compilation Group of People?s Republic of China. JGJ 94—2008 Technical code for building pile foundation[S]. Beijing：China Architecture and Building Press，2008.(in Chinese))
[14] 曾 革，周志刚. 桩承式加筋垫层路堤地基承载力计算方法[J]. 中南大学学报：自然科学版，2010，41(3)：1 158–1 164.(ZENG Ge，ZHOU Zhigang. Calculation method for ground bearing capacity of pile-supported reinforced cushion embankment[J]. Journal of Central South University：Science and Technology，2010，41(3)：1 158– 1 164.(in Chinese))
[15] JONES B M，PLAUT R H，FILZ G M. Analysis of geosynthetic reinforcement in pile-supported embankments，part I：3D plate model[J]. Geosynthetics International，2010，17(2)：59–67.
2013, Vol. 32 
