Model tests on stress and deformation properties of composite foundation with controllable rigid piles and drainage bodies
ZHOU Zhi-jun1, CHEN Chang-fu2, XIAO Shui-qiang3
1. School of Civil Engineering and Architecture, Wuyi University, Jiangmen 529020, China; 2. Institute of Geotechnical Engineering, Hunan University, Changsha 410082, China; 3. Maoming Municipal Bureau of Transport, Maoming 525000, China
Abstract：In a composite foundation, the deformations of piles and soils are affected by many factors. The cushion is difficult to coordinate and match the differential settlement between all piles and soils. Therefore the piles often carry the excessive loads and are destroyed, or the piles bear too small loads and are wasted. A new composite foundation composed of controllable rigid piles and drainage bodies is proposed. The differential settlement between piles and soils is coordinated by the grouting device at the top of piles in the composite foundation, rigid piles hardly carry the upper loads before grouting, and the foundation soils are fully consolidated and their bearing capacity is improved. After grouting, the rigid piles begin to support the loads, and the piles and soils work together to share the loads and to control settlement. The stress and deformation properties of the composite foundation are studied through indoor model tests. The results show that the settlement of the new composite foundation mainly increases before grouting and is effectively controlled after grouting. Moreover, the new composite foundation can effectively reduce the differential settlement. The load pressure shared by the cover plate on piles is less than that shared by the soils between piles before grouting, and the pressure shared by the cover plate increases rapidly after grouting, while that by the soils between piles decreases correspondingly. The bearing capacity of rigid piles can be controlled by grouting.
周志军, 陈昌富, 肖水强. 可控刚性桩与排水体组合型复合地基受力与变形特性的模型试验研究[J]. 岩土工程学报, 2020, 42(12): 2308-2315.
ZHOU Zhi-jun, CHEN Chang-fu, XIAO Shui-qiang. Model tests on stress and deformation properties of composite foundation with controllable rigid piles and drainage bodies. Chinese J. Geot. Eng., 2020, 42(12): 2308-2315.
[1] 赵维炳, 刘国楠, 李荣强. 控制工后变形新一代软基处理技术的发展[J]. 土木工程学报, 2004, 37(6): 78-81. (ZHAO Wei-bing, LIU Guo-nan, LI Rong-qiang.Development of new improving techniques for controlling post-construction deformation of soft soil ground[J]. China Civil Engineering Journal, 2004, 37(6): 78-81.(in Chinese)) [2] ZHOU Hai-zou, ZHENG Gang, YU Xiao-xuan, et al.Bearing capacity and failure mechanism of ground improved by deep mixed columns[J]. Journal of Zhejiang University-Science A (Applied Physics & Engineering), 2018, 19(4): 266-276. [3] ZOU Xin-jun, ZHAO Zeng-ming, XU Dong-bin.Consolidation analysis of composite foundation with partially penetrated cement fly-ash gravel(CFG) piles under changing permeable boundary conditions[J]. Journal of Central South University, 2015, 22: 4019-4026. [4] 陈昌富, 周志军. 双向增强体复合地基桩土应力比分析[J]. 岩土力学, 2009, 30(9): 2660-2666. (CHEN Chang-fu, ZHOU Zhi-jun.Analysis of pile-soil stress ratio for double reinforced composite ground[J]. Rock and Soil Mechanics, 2009, 30(9): 2660-2666. (in Chinese)) [5] 赵明华, 刘猛, 马缤辉, 等. 路堤下“土工格室+碎石桩”双向增强复合地基桩土应力比及沉降计算[J]. 中国公路学报, 2016, 29(5): 1-10. (ZHAO Ming-hua, LIU Meng, MA Bin-hui, et al.Calculation for stress concentration ratio and settlement of bidirectional reinforced composite foundation consisting of geocell mattress and stone column under embankment[J]. China Journal of Highway and Transport, 2016, 29(5): 1-10. (in Chinese)) [6] 李波, 黄茂松, 程岳, 等. 路堤荷载下长短桩组合型复合地基现场试验与数值模拟[J]. 中国公路学报, 2013, 26(1): 9-14. (LI Bo, HUANG Mao-song, CHENG Yue, et al.Field test and numerical analysis of composite foundation with long and short piles under embankment[J]. China Journal of Highway and Transport, 2013, 26(1): 9-14. (in Chinese)) [7] 沈宇鹏, 田亚护, 冯瑞玲. GC-CFG组合桩复合地基处理高速铁路基底的应用研究[J]. 土木工程学报, 2013, 46(2): 136-142. (SHEN Yu-peng, TIAN Ya-hu, FENG Rui-ling.Study on treatment of GC-CFG composite piles to base of high-speed railway[J]. China Civil Engineering Journal, 2013, 46(2): 136-142. (in Chinese)) [8] 杨涛, 李超. 刚性基础下组合渗流碎石桩-不排水桩复合地基固结分析[J]. 岩石力学与工程学报, 2018, 37(11): 2631-2640. (YANG Tao, LI Chao.Consolidation analysis of stone column-impervious pile composite ground underneath rigid foundation considering radial and vertical flows within stone columns[J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37(11): 2631-2640.(in Chinese)) [9] 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)) [10] 齐昌广, 刘汉龙, 陈永辉, 等. 塑料套管混凝土桩承载试验及沉降计算方法研究[J]. 岩土工程学报, 2016, 38(12): 2302-2308. (QI Chang-guang, LIU Han-long, CHEN Yong-hui, et al.Bearing capacity tests and settlement calculation method of plastic tube cast-in-place concrete pile[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(12): 2302-2308. (in Chinese)) [11] 刘吉福, 郑刚, 龚晓南. 附加应力法计算刚性桩复合地基路基沉降[J]. 岩土工程学报, 2018, 40(11): 1995-2002. (LIU Ji-fu, ZHENG Gang, GONG Xiao-nan.Superimposed stress method to calculate settlement of embankment with rigid-pile composite foundation[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(11): 1995-2002. (in Chinese)) [12] 郑刚, 刘双菊, 伍止超. 不同厚度褥垫层刚性桩复合地基工作特性研究[J]. 岩土力学, 2006, 27(8): 1357-1360. (ZHENG Gang, LIU Shuang-ju, WU Zhi-chao.Study on behavior of rigid pile composite ground with different cushion thicknesses[J]. Rock and Soil Mechanics, 2006, 27(8): 1357-1360. (in Chinese)) [13] 周志军, 郑昊. 桩体刺入全过程褥垫层的工作特性[J]. 土木与环境工程学报, 2019, 41(3): 41-48. (ZHOU Zhi-jun, ZHENG Hao.Working characteristics of cushion subjected to pile penetration[J]. Journal of Civil and Environmental Engineering, 2019, 41(3): 41-48. (in Chinese)) [14] 亓乐, 施建勇, 曹权. 刚性桩复合地基垫层合理厚度确定方法[J]. 岩土力学, 2009, 30(11): 3423-3428. (QI Le, SHI Jian-yong, CAO Quan.Method for calculating rational thickness of cushion in rigid pile composite ground[J]. Rock and Soil Mechanics, 2009, 30(11): 3423-3428. (in Chinese)) [15] 周志军, 王连坤, 王敏容, 等. 复合地基中褥垫层的极限下限分析[J]. 中国科技论文, 2013, 8(11): 1153-1158. (ZHOU Zhi-jun, WANG Lian-kun, WANG Min-rong, et al.Lower bound limit analysis of cushion in composite foundation[J]. China Science Paper, 2013, 8(11): 1153-1158. (in Chinese)) [16] 五邑大学. 后注浆带帽刚性桩与排水体组合型地基处理方法: 中国专利, ZL201310067750.6 [P].2016-08-17. (WUYI University. Ground treatment method of post-grouting rigid pile with cap and drainage body: China Patent, ZL201310067750.6 [P].2016-08-17. (in Chinese)) [17] 五邑大学. 可控刚性桩+排水体+加筋垫层组合型地基: 中国专利, ZL201510798115.4 [P].2018-12-28. (WUYI University. Controllable rigid pile + drainage body + reinforced cushion composite foundation: China Patent, ZL201510798115.4 [P].2018-12-28. (in Chinese)) [18] 建筑桩基技术规范:JGJ94–2008[S]. 2008. (Technical Code for Building Pile Foundations: JGJ94–2008[S]. 2008. (in Chinese)) [19] 建筑地基处理技术规范:JGJ79–2012[S]. 2012. (Technical Code for Ground Treatment of Buildings: JGJ79–2012[S]. 2012. (in Chinese))
