高铁软基工后沉降特性与加固效果
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摘要
高速铁路深厚软土地基的工后沉降控制是世界性难题,为此,依托于沪宁城际高速铁路,统计分析100余公里路基段3a运营期的沉降监测数据,将工后沉降划分成可以评价沉降控制效果的4个等级,并结合沉降推测评估,将其区划为稳定、基本稳定、临界超限与超限4个状态;针对地基处理措施工后沉降控制效果分析中传统方法存在的问题,提出"当量软弱土厚度"概念,可量化分析地基处理措施的工后沉降控制效果。分析表明:高铁路基的工后沉降与当量软弱土厚度成正相关关系,不同处理措施加固地基存在一个"临界"当量软弱土厚度,桩-板结构处理的地基沉降处于临界超限时,对应的当量软弱土厚度是桩-筏复合地基的1.7倍,是桩-网复合地基的2.2倍;桩-板结构处理的地基单位当量软弱土厚度工后沉降值仅为桩-筏复合地基的59%,桩-筏复合地基是桩-网复合地基的76%。
How to control the post-construction settlement of deep soft soil foundation in high-speed railway is a worldwide problem.Therefore,analysis of settlement monitoring data of 100 km subgrade during the operation period of 3 years based on the Shanghai-Nanjing inter-city high-speed railway is performed in this paper,and the post-construction settlement is divided into four grades which can be used to evaluate the settlement control effect.Combined with the sedimentation estimation,it is further divided into four states:stability,basic stability,critical overrun and overrun.Aiming at addressing the problems existing in the routine analysis method of post-construction settlement control of foundation treatment measures,the concept of " equivalent soft soil thickness" is proposed,which can quantitatively analyze the effect of post-construction settlement control of foundation treatment measures. Results obtained from the comprehensive analysis show that the post-construction settlement of the high-speed railway subgrade is positively related to the thickness of the weak soil.There exists a "critical" equivalent soft soil thickness in the different treatment measures,and the thickness of the equivalent settlement of the foundation in the pile-soil is 1.7 times of that of pile-raft composite foundation,and it is 2.2 times of pile-net composite foundation.Pile-plate structure treatment foundation is equivalent to weak soil thickness,and its corresponding post-construction settlement is only 59% of pile-raft composite foundation.In addition,the raft composite foundation is 76% of the pile-net composite foundation.
How to control the post-construction settlement of deep soft soil foundation in high-speed railway is a worldwide problem.Therefore,analysis of settlement monitoring data of 100 km subgrade during the operation period of 3 years based on the Shanghai-Nanjing inter-city high-speed railway is performed in this paper,and the post-construction settlement is divided into four grades which can be used to evaluate the settlement control effect.Combined with the sedimentation estimation,it is further divided into four states:stability,basic stability,critical overrun and overrun.Aiming at addressing the problems existing in the routine analysis method of post-construction settlement control of foundation treatment measures,the concept of " equivalent soft soil thickness" is proposed,which can quantitatively analyze the effect of post-construction settlement control of foundation treatment measures. Results obtained from the comprehensive analysis show that the post-construction settlement of the high-speed railway subgrade is positively related to the thickness of the weak soil.There exists a "critical" equivalent soft soil thickness in the different treatment measures,and the thickness of the equivalent settlement of the foundation in the pile-soil is 1.7 times of that of pile-raft composite foundation,and it is 2.2 times of pile-net composite foundation.Pile-plate structure treatment foundation is equivalent to weak soil thickness,and its corresponding post-construction settlement is only 59% of pile-raft composite foundation.In addition,the raft composite foundation is 76% of the pile-net composite foundation.
引文
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[9]徐林荣,王宏贵,左珅.高速铁路沉降控制复合桩基的性状试验研究[J].岩土力学,2012,33(9):2605-2612.XU L R,WANG H G,ZUO S.Teststudy of performance of composite pile foundation of high-speed railway controlling settlement[J].Rock and Soil Mechanics,2012,33(9):2605-2612.(in Chinese)
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[11]LI J W,GUAN L J.Study on the settlement characteristics and reinforcement technology of unsaturated soil ground of high-speed railway[C]//International Conference on Transportation Geotechnics.2012.
[12]徐林荣,牛建东,吕大伟.软基路堤桩-网复合地基试验研究[J].岩土力学,2007,28(10):2149-2154.XU L R,NIU J D,LYU D W.Experimental study on pile-net composite foundation of high-speed railway on soft soils[J].Rock and Soil Mechanics,2007,28(10):2149-2154.(in Chinese)
[13]W S R.Geosynthetics in civil engineering(inassociation with the textile institut)[M].Woodhead Publishing Limited,2007.
[14]王良民,朱长歧,阎钶.软土路基沉降与软土层厚度及填土高度的关系分析[J].岩土力学,2003,24(10):432-434.WANG L M,ZHU C Q,YAN K.Analysis for settlement of embankment connected with soft soil thickness and fill depth on soft soil road bed[J].Rock&Soil Mechanics,2003,24(10):432-434.(in Chinese)
[15]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2002.
[2]KIM Y H,EUM K Y,HAN S J,et al.A study on settlement characteristics of earthwork subgrade with lowering the groundwater in high-speed railway[J].2015,31(5):67-74.
[3]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):50-54.ZUO S,WANG M,XU L R,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):50-54.(in Chinese)
[4]刘升传,曹渊.新建铁路软土路基沉降规律研究[J].铁道工程学报,2010,(5):1-3.LIU S C,CAO Y.Research on settlement law of soft soil subgrade of new railway[J].Journal of Railway Engineering Society,2010,5:1-3.(in Chinese)
[5]王炳龙,杨龙才,周顺华.CFG桩控制深厚层软土地基沉降的试验研究[J].铁道学报,2007,28(6):112-116.WANG B L,YANG L C,ZHOU S H.Experimental study on the settlement control of high-speed railway subgrade over deep soft clay reinforced by CFGpiles[J].Journal of the China Railway Society,2007,28(6):112-116.(in Chinese)
[6]刘俊飞,赵国堂,马建林.铁路CFG桩桩网、桩筏复合地基沉降变形特点对比[J].西南交通大学学报,2012,47(5):189-193.LIU J F,ZHAO G T,MA J L.Comparison of settlement characteristics of CFG Pile-Net and pile-raft composite foundation under railway embankments[J].Journal of Southwest Jiaotong University,2012,47(5):189-193.(in Chinese)
[7]李波,冷景岩.高速铁路CFG桩-筏结构沉降控制现场试验[J].铁道工程学报,2014,(2):48-52.LI B,LENG J Y.Research on settlement control effect of CFG pile-raft structure based on field test of highspeed railway[J].Journal of Railway Engineering Society,2014,(2):48-52.(in Chinese)
[8]李昌宁,王炳龙,周顺华.CFG桩-网复合结构软基加固技术及其实际应用[J].铁道工程学报,2006(1):27-31.LI C N,WANG B L,ZHOU S H.Reinforcement technique for subgrade in soft soil zone by composite structure of CFG Pile-net and its application[J].Journal of Railway Engineering Society,2006(1):27-31.(in Chinese)
[9]徐林荣,王宏贵,左珅.高速铁路沉降控制复合桩基的性状试验研究[J].岩土力学,2012,33(9):2605-2612.XU L R,WANG H G,ZUO S.Teststudy of performance of composite pile foundation of high-speed railway controlling settlement[J].Rock and Soil Mechanics,2012,33(9):2605-2612.(in Chinese)
[10]STEWART M E,NAVIN M P,FILZ G M.Analysis of a column-supported test embankment at the i-95/route1 interchange[C]//Proceedings of Geotechnical Engineering for Transportation Projects,Reston:ASCE Publications,2004:1337-1345.
[11]LI J W,GUAN L J.Study on the settlement characteristics and reinforcement technology of unsaturated soil ground of high-speed railway[C]//International Conference on Transportation Geotechnics.2012.
[12]徐林荣,牛建东,吕大伟.软基路堤桩-网复合地基试验研究[J].岩土力学,2007,28(10):2149-2154.XU L R,NIU J D,LYU D W.Experimental study on pile-net composite foundation of high-speed railway on soft soils[J].Rock and Soil Mechanics,2007,28(10):2149-2154.(in Chinese)
[13]W S R.Geosynthetics in civil engineering(inassociation with the textile institut)[M].Woodhead Publishing Limited,2007.
[14]王良民,朱长歧,阎钶.软土路基沉降与软土层厚度及填土高度的关系分析[J].岩土力学,2003,24(10):432-434.WANG L M,ZHU C Q,YAN K.Analysis for settlement of embankment connected with soft soil thickness and fill depth on soft soil road bed[J].Rock&Soil Mechanics,2003,24(10):432-434.(in Chinese)
[15]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2002.