加固范围及边坡坡率对CFG桩–网复合地基受力变形特性影响分析
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摘要
通过开展相似比为1∶80的室内离心模型试验,并结合数值模拟方法,探究不同加固范围与不同边坡坡率对CFG桩–网复合地基受力变形特性的影响。分析表明:填筑期竖向位移明显增大,放置期与运营期增长缓慢并趋于稳定;当加固范围缩小时,边坡坡率为1∶1.5工况下的竖向位移增长趋势大于边坡坡率为1∶1.75工况下的,表现出边坡越陡对加固范围敏感性越高的规律;水平变形方面在坡脚及坡脚外5m位置处数值较大,当加固范围变化时坡脚处水平变形在土层交界面位置出现反弯点,且加固范围越小反弯程度越大;相同荷载作用下半加固复合地基桩顶应力大于全加固复合地基,桩间土应力则表现出相反的规律;边坡坡率相同时桩–土应力比随加固范围缩小表现出一定程度的增大。
In order to study the effect of the strengthening area and the slope rate on bearing and deforming behaviors of CFG pile composite foundations,centrifuge test with a similarity ratio of 1∶80 and numerical simulation were conducted. The results show that the vertical displacement has a significant increase during embankment fill period and a slow growth during the placement and operation periods. With decreasing the strengthening area,the increasing trend of the vertical displacement with a slope ratio of 1∶1.5 is greater than that of 1∶1.75,which indicates that a steeper slope results in more sensitivity of the strengthening area. The horizontal displacements at the toe of the slope and 5 meters away from the toe of the slope are greater than those at other places. When the strengthening area decrease,a anti-bend point of the horizontal displacement at the toe of the slope occurs at the soil interface,and the anti-bend rate increases with decreasing the strengthening area. Under the same load,the stress on the pile top in a half strengthening composite foundation is greater than that in a whole strengthening composite foundation,but the earth stress between piles shows a opposite pattern. The pile-soil stress ratio shows a increase trend with the decrease of the strengthening area with a same slope rate.
In order to study the effect of the strengthening area and the slope rate on bearing and deforming behaviors of CFG pile composite foundations,centrifuge test with a similarity ratio of 1∶80 and numerical simulation were conducted. The results show that the vertical displacement has a significant increase during embankment fill period and a slow growth during the placement and operation periods. With decreasing the strengthening area,the increasing trend of the vertical displacement with a slope ratio of 1∶1.5 is greater than that of 1∶1.75,which indicates that a steeper slope results in more sensitivity of the strengthening area. The horizontal displacements at the toe of the slope and 5 meters away from the toe of the slope are greater than those at other places. When the strengthening area decrease,a anti-bend point of the horizontal displacement at the toe of the slope occurs at the soil interface,and the anti-bend rate increases with decreasing the strengthening area. Under the same load,the stress on the pile top in a half strengthening composite foundation is greater than that in a whole strengthening composite foundation,but the earth stress between piles shows a opposite pattern. The pile-soil stress ratio shows a increase trend with the decrease of the strengthening area with a same slope rate.
引文
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[11]李懿,王连俊,栾光日,等.高速铁路站场咽喉区复合地基的工程特性研究[J].铁道学报,2014,36(12):90-96.(LI Yi,WANGLianjun,LUAN Guangri,et al.Research on consolidation characteristics of composite foundation in the throat area of highspeed railway station[J].Journal of the China Railway Society,2014,36(12):90-96.(in Chinese))
[12]沈宇鹏,毛远凤,荆鹏,等.PHC与CFG桩复合地基在高速铁路基底中处理效果试验对比[J].岩石力学与工程学报,2014,33(增2):4 174-4 180.(SHEN Yupeng,MAO Yuanfeng,JING Peng,et al.Experimental effect contrast between PHC and CFG pile-raft composite foundation in high speed railway base treatment[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Supp.2):4 174-4 180.(in Chinese))
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[14]张峰,刘莹,许兆义,等.武广高铁CFG桩复合地基工后沉降影响因素[J].西南交通大学学报,2015,50(5):783-788.(ZHANG Feng,LIU Ying,XU Zhaoyi,et al.Factors Influencing subgrade post-construction settlement of CFG pile composite foundation in Wuhan-Guangzhou high-speed railway[J].Journal of Southwest Jiaotong University,2015,50(5):783-788.(in Chinese))
[15]高广运,李绍毅.列车运行引起的CFG桩复合路基动力响应分析[J].振动与冲击,2015,34(24):135-143.(GAO Guangyun,LI Shaoyi.Dynamic response of CFG pile composite subgrade induced by moving train loadings[J].Journal of Vibration and Shock,2015,34(24):135-143.(in Chinese))
[16]刘杰,张可能.复合地基荷载传递规律及变形计算[J].中国公路学报,2004,17(1):20-23.(LIU Jie,ZHANG Keneng.Load transfer law and deformation calculating of the composite foundation[J].China Journal of Highway and Transport,2004,17(1):20-23.(in Chinese))
[17]马明正,海振雄,叶阳升,等.高速铁路CFG桩复合地基沉降计算适用方法研究[J].中国铁道科学,2014,35(2):7-13.(MAMingzheng,HAI Zhenxiong,YE Yangsheng,et al.Applicable method for settlement calculation of CFG Pile composite foundation for high speed railway[J].China Railway Science,2014,35(2):7-13.(in Chinese))
[18]赵明志,罗强,崔维孝,等.高速铁路深厚地层CFG桩复合地基变形计算经验系数分析[J].铁道学报,2015,37(1):69-76.(ZHAO Mingzhi,LUO Qiang,CUI Weixiao,et al.Analysis on deformation calculation empirical coefficient of CFG pile composite foundation of deep layer in high-speed railway[J].Journal of the China Railway Society,2015,37(1):69-76.(in Chinese))
[19]罗强,陆清元.考虑桩土滑移的路堤下刚性桩复合地基沉降计算[J].中国公路学报,2018,31(1):20-30.(LUO Qiang,LU Qingyuan.Settlement calculation of rigid pile composite foundation considering pile-soil relative slip under embankment load[J].China Journal of Highway and Transport,2018,31(1):20-30.(in Chinese))
[20]王占江,白建波,卢萍珍.CFG桩布桩范围对路基水平位移影响数值分析[J].路基工程,2011,(1):94-96.(WANG Zhanjiang,BAIJianbo,LU Pingzhen.Numerical analysis on the influence of CFG Pile layout on subgrade horizontal displacement[J].Subgrade Engineering,2011,(1):94-96.(in Chinese))
[21]CRAIG W H.Edouard phillips and the idea of centrifuge modeling[J].Geotechnique,1989,(39):679-700.
[22]冯振,殷跃平.我国土工离心模型试验技术发展综述[J].工程地质学报,2011,19(3):323-331.(FENG Zhen,YIN Yueping.Statw of the art review of geotechnical centrifuge modeling test in china[J].Journal of Engineering Geology,2011,19(3):323-331.(in Chinese))
[23]邢建营,邢义川,梁建辉.土工离心模型试验研究的进展与思考[J].水利与建筑工程学报,2005,3(1):27-31.(XING Jianying,XINGYichuan,LIANG Jianhui.Development and thoughts of geotechnical centrifuge modeling[J].Journal of Water Resources and Architectural Engineering,2005,3(1):27-31.(in Chinese))
[2]肖宏,蒋关鲁,魏永幸.遂渝线无碴轨道桩网结构地基处理技术[J].铁道工程学报,2006,94(4):22-25.(XIAO Hong,JIANG Guanlu,WEI Yongxing.Discussion of Sui-Yu railway line ballastless track column-net structure[J].Journal of Railway Engineering Society,2006,94(4):22-25.(in Chinese))
[3]詹永祥,蒋关鲁,魏永幸.无碴轨道桩板结构路基在地震荷载下的动力响应分析[J].中国铁道科学,2006,27(6):22-26.(ZHANYongxiang,JIANG Guanlu,WEI Yongxing.Dynamic response analysis on the pile-plank structure roadbed of ballastless track under earthquake load[J].China Railway Science,2006,27(6):22-26.(in Chinese))
[4]丁小军,王旭,张延杰,等.大型油罐CFG桩复合地基变形与承载性能试验研究[J].岩石力学与工程学报,2013,32(9):1 851-1 857.(DING Xiaojun,WANAG Xu,ZHANG Yanjie,et al.Experimental study of bearing and deformation features of CFG-pile composite ground for large oil storage tanks[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(9):1 851-1 857.(in Chinese))
[5]蒋泽中,肖宏,蒋关鲁,等.桩网结构加固土质路基的离心机模型试验研究[J].铁道工程学报,2013,(11):18-22.(JIANGZezhong,XIAO Hong,JIANG Guanlu,et al.Centrifugal model test study on soil subgrade reinforced by column-net structure[J].Journal of Railway Engineering Society,2013,(11):18-22.(in Chinese))
[6]肖东,蒋关鲁,林展展,等.过渡段地基加固作用对桥台桩工作性状的影响分析[J].中南大学学报:自然科学版,2017,48(3):820-829.(XIAO Dong,JIANG Guanlu,LIN Zhanzhan,et al.Analysis on working properties of abutment piles considering foundation reinforcement of approach embankment[j].Journal of Central South University:Science and Technology,2017,48(3):820-829.(in Chinese))
[7]刘飞成,张建经.斜坡基底软土桩-网复合地基变形特性离心试验研究[J].岩石力学与工程学报,2018,37(1):209-219.(LIU Feicheng,ZHANG Jianjing.Centrifuge test deformation characteristics of pile-geogrid composite foundation in soft soil under slope[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(1):209-219.(in Chinese))
[8]李连祥,符庆宏.临近基坑开挖复合地基侧向力学性状离心试验研究[J].土木工程学报,2017,50(6):85-94.(LI Lianxiang,FUQinghong.Lateral mechanical behavior of composite ground due to adjacent excavation:centrifuge model test[J].China Civil Engineering Journal,2017,50(6):85-94.(in Chinese))
[9]黄生根.柔性荷载下带帽CFG桩复合地基承载性状的试验研究[J].岩土工程学报,2013,35(增2):564-568.(HUANG Shenggen.Experimental Study on bearing behaviors of composite foundation with CFG piles with caps under flexible loads[J].Chinese Journal of Geotechnical Engineering,2013,35(Supp.2):564-568.(in Chinese))
[10]左珅,王敏,徐林荣,等.高速铁路中低压缩性土桩-筏(网)地基加固效果研究[J].中南大学学报:自然科学版,2014,45(5):1 590-1 597.(ZUO Shen,WANG Min,XU Linrong,et al.Research on reinforce effect of high-speed railway low and medium compressible soil pile-raft(net)foundation[J].Journal of Central South University:Science and Technology,2014,45(5):1 590-1 597.(in Chinese))
[11]李懿,王连俊,栾光日,等.高速铁路站场咽喉区复合地基的工程特性研究[J].铁道学报,2014,36(12):90-96.(LI Yi,WANGLianjun,LUAN Guangri,et al.Research on consolidation characteristics of composite foundation in the throat area of highspeed railway station[J].Journal of the China Railway Society,2014,36(12):90-96.(in Chinese))
[12]沈宇鹏,毛远凤,荆鹏,等.PHC与CFG桩复合地基在高速铁路基底中处理效果试验对比[J].岩石力学与工程学报,2014,33(增2):4 174-4 180.(SHEN Yupeng,MAO Yuanfeng,JING Peng,et al.Experimental effect contrast between PHC and CFG pile-raft composite foundation in high speed railway base treatment[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(Supp.2):4 174-4 180.(in Chinese))
[13]张爽,唐春安,张向东.季节性冻土地区高铁路基沉降研究[J].东北大学学报:自然科学版,2013,34(8):1 202-1 205.(ZHANGShuang,TANG Chun′an,ZHANG Xiangdong.Subgrade settlement of high-speed railway in seasonal frozen soil area[J].Journal of Northeastern University:Natural Science,2013,34(8):1 202-1 205.(in Chinese))
[14]张峰,刘莹,许兆义,等.武广高铁CFG桩复合地基工后沉降影响因素[J].西南交通大学学报,2015,50(5):783-788.(ZHANG Feng,LIU Ying,XU Zhaoyi,et al.Factors Influencing subgrade post-construction settlement of CFG pile composite foundation in Wuhan-Guangzhou high-speed railway[J].Journal of Southwest Jiaotong University,2015,50(5):783-788.(in Chinese))
[15]高广运,李绍毅.列车运行引起的CFG桩复合路基动力响应分析[J].振动与冲击,2015,34(24):135-143.(GAO Guangyun,LI Shaoyi.Dynamic response of CFG pile composite subgrade induced by moving train loadings[J].Journal of Vibration and Shock,2015,34(24):135-143.(in Chinese))
[16]刘杰,张可能.复合地基荷载传递规律及变形计算[J].中国公路学报,2004,17(1):20-23.(LIU Jie,ZHANG Keneng.Load transfer law and deformation calculating of the composite foundation[J].China Journal of Highway and Transport,2004,17(1):20-23.(in Chinese))
[17]马明正,海振雄,叶阳升,等.高速铁路CFG桩复合地基沉降计算适用方法研究[J].中国铁道科学,2014,35(2):7-13.(MAMingzheng,HAI Zhenxiong,YE Yangsheng,et al.Applicable method for settlement calculation of CFG Pile composite foundation for high speed railway[J].China Railway Science,2014,35(2):7-13.(in Chinese))
[18]赵明志,罗强,崔维孝,等.高速铁路深厚地层CFG桩复合地基变形计算经验系数分析[J].铁道学报,2015,37(1):69-76.(ZHAO Mingzhi,LUO Qiang,CUI Weixiao,et al.Analysis on deformation calculation empirical coefficient of CFG pile composite foundation of deep layer in high-speed railway[J].Journal of the China Railway Society,2015,37(1):69-76.(in Chinese))
[19]罗强,陆清元.考虑桩土滑移的路堤下刚性桩复合地基沉降计算[J].中国公路学报,2018,31(1):20-30.(LUO Qiang,LU Qingyuan.Settlement calculation of rigid pile composite foundation considering pile-soil relative slip under embankment load[J].China Journal of Highway and Transport,2018,31(1):20-30.(in Chinese))
[20]王占江,白建波,卢萍珍.CFG桩布桩范围对路基水平位移影响数值分析[J].路基工程,2011,(1):94-96.(WANG Zhanjiang,BAIJianbo,LU Pingzhen.Numerical analysis on the influence of CFG Pile layout on subgrade horizontal displacement[J].Subgrade Engineering,2011,(1):94-96.(in Chinese))
[21]CRAIG W H.Edouard phillips and the idea of centrifuge modeling[J].Geotechnique,1989,(39):679-700.
[22]冯振,殷跃平.我国土工离心模型试验技术发展综述[J].工程地质学报,2011,19(3):323-331.(FENG Zhen,YIN Yueping.Statw of the art review of geotechnical centrifuge modeling test in china[J].Journal of Engineering Geology,2011,19(3):323-331.(in Chinese))
[23]邢建营,邢义川,梁建辉.土工离心模型试验研究的进展与思考[J].水利与建筑工程学报,2005,3(1):27-31.(XING Jianying,XINGYichuan,LIANG Jianhui.Development and thoughts of geotechnical centrifuge modeling[J].Journal of Water Resources and Architectural Engineering,2005,3(1):27-31.(in Chinese))