重复机车荷载作用下青藏铁路冻土路基累积塑性变形分析
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摘要
在青藏铁路北麓河试验段选取素填土路基断面,于暖季7月份开展列车通过实时振动测试,获得铁路货运机车振动荷载作用下路肩处的加速度时程曲线。将现场测得的加速度时程曲线作为有限元计算的荷载边界条件,通过非线性动力计算获得路基坡脚和天然地表处的加速度时程曲线,分析机车振动沿路基的传递衰减特性。阐明路基土体内部动应力分布特征和沿深度的衰减规律。应用累积塑性应变模型,对多年冻土路基在重复机车荷载作用下的永久变形进行初步分析和预测。研究结果表明:机车荷载作用所导致的路基变形随着荷载作用次数的增加逐渐趋于稳定。在机车作用1年之后,路基累计变形为27.74 mm,机车作用10年之后,该变形值发展为40.12 mm。
In order to estimate the vibration effect of the train loading, a traditional sand-gravel embankment at the Beiluhe segment along the Qinghai-Tibet Railway was selected, and the strong motion tests were carried out in warm season. The waveforms of acceleration history deduced by the train vibration near railway tracks were collected when train passes, and the typical acceleration history waveform was used as the acceleration boundary condition to simulate the dynamic load effect. By applying the Finite Element Method, the dynamic response of embankment in permafrost region under the train loading was studied, and the transmission and attenuation characteristics of the train loading were obtained. Then the stress ratio of the subgrade soils at different depths was obtained as well. On this basis, the strain accumulation model was applied to study the permanent deformation of the subgrade soils under the influence of repeated train loading. The results show that the permanent deformation deduced by the dynamic load gradually increases with the increase of the times of train load, and the deformation tends to be stable with the increase of time as well. The deformation of subgrade soils deduced by vibration effect under repeated train load in 1 year reaches upto 27.74 mm, while the value could reach upto 40.12 mm in 10 years.
In order to estimate the vibration effect of the train loading, a traditional sand-gravel embankment at the Beiluhe segment along the Qinghai-Tibet Railway was selected, and the strong motion tests were carried out in warm season. The waveforms of acceleration history deduced by the train vibration near railway tracks were collected when train passes, and the typical acceleration history waveform was used as the acceleration boundary condition to simulate the dynamic load effect. By applying the Finite Element Method, the dynamic response of embankment in permafrost region under the train loading was studied, and the transmission and attenuation characteristics of the train loading were obtained. Then the stress ratio of the subgrade soils at different depths was obtained as well. On this basis, the strain accumulation model was applied to study the permanent deformation of the subgrade soils under the influence of repeated train loading. The results show that the permanent deformation deduced by the dynamic load gradually increases with the increase of the times of train load, and the deformation tends to be stable with the increase of time as well. The deformation of subgrade soils deduced by vibration effect under repeated train load in 1 year reaches upto 27.74 mm, while the value could reach upto 40.12 mm in 10 years.
引文
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[19]LI Dingqing,Selig E T.Method for railroad track foundation design(Ⅰ):development[J].Journal of Geotechnical and Geoenviromental Engineering,1998,124(4):316-322.
[20]LI Dingqing,Selig E T.Method for railroad track foundation design(Ⅱ):application[J].Journal of Geotechnical and Geoenviromental Engineering,1998,124(4):323-329.
[21]边学成,曾二贤,陈云敏.列车交通荷载作用下软土路基的长期沉降[J].岩土力学,2008,29(11):2990-2996.BIAN Xuecheng,ZENG Erxian,CHEN Yunmin.Long-term settlements of soft soil ground induced by train traffic loadings[J].Rock and Soil Mechanics,2008,29(11):2990-2996.
[22]董亮.高速铁路路基动力特性及列车循环荷载作用下变形性质研究[D].北京:北京交通大学,2008.DONG Liang.Dynamic response and cumulative deformation for high-speed railway subgrade due to moving loads[D].Beijing:Beijing Jiaotong University,2008.
[23]焦贵德,赵淑萍,马巍.冻融循环后高温冻结粉土在循环荷载下的动力特性试验研究[J].土木工程学报,2010,43(12):107-113.JIAO Guide,ZHAO Shuping,MA Wei.Experimental study of the dynamic characteristics of warm-frozen silt after freeze-thaw cycles under cyclic loading[J].China Civil Engineering Journal,2010,43(12):107-113.
[2]王兰民,孙军杰.特殊土动力学的发展战略与展望[J].西北地震学报,2007,29(1):88-93.WANG Lanmin,SUN Junjie.Development strategy and prospects for study of special soil dynamics[J].Northwestern Seismological Journal,2007,29(1):88-93.
[3]马巍,牛富俊,穆彦虎.青藏高原重大冻土工程的基础研究[J].地球科学进展,2012,27(11):1185-1191.MA Wei,NIU Fujun,MU Yanhu.Basic research on the major permafrost projects in the Qinghai-Tibet plateau[J].Advances in Earth Science,2012,27(11):1185-1191.
[4]孙志忠,马巍,党海明,等.青藏铁路多年冻土区路基变形特征及其来源[J].岩土力学,2013,34(9):2667-2671.SUN Zhizhong,MA Wei,DANG Haiming,et al.Characteristics and causes of embankment deformation for Qinghai-Tibet Railway in permafrost regions[J].Rock and Soil Mechanics,2013,34(9):2667-2671.
[5]吴志坚,陈拓,马巍.机车荷载作用下青藏铁路多年冻土区普通路基的蠕变分析[J].岩土力学,2011,32(增2):83-87.WU Zhijian,CHEN Tuo,MA Wei.The creep analysis of plain fill embankment at the permafrost regions along Qinghai-Tibet Railway under train dynamic load[J].Rock and Soil Mechanics,2011,32(Suppl 2):83-87.
[6]王立娜.青藏铁路多年冻土区列车行驶路基振动反应与累积永久变形[D].哈尔滨:哈尔滨工业大学,2013.WANG Lina.Train-induced dynamic response and permanent deformation of embankment in permafrost regions along Qinghai-Tibet Railway[D].Harbin:Harbin Institute of Technology,2013.
[7]李进军,黄茂松,王育德.交通荷载作用下软土地基累积塑性变形分析[J].中国公路学报,2006,19(1):1-5.LI Jinjun,HUANG Maosong,WANG Yude.Analysis of cumulative plastic deformation of soft clay foundation under traffic loading[J].China Journal of Highway and Transport,2006,19(1):1-5.
[8]董亮,赵成刚,蔡德钩.高速铁路路基的动力响应分析方法[J].工程力学,2008,25(11):231-236.DONG Liang,ZHAO Chenggang,CAI Degou.Method for dynamic response of subgrade subjected to high-speed moving load[J].Engineering Mechanics,2008,25(11):231-236.
[9]Monismith C L,Ogawa N,Freeme C R.Permanent deformation characteristics of subgrade soils due to repeated loading[J].Transport Research Record,1975,537:1-17.
[10]LI Dingqing,Selig Ernest T.Cumulative plastic deformation for fine-grained subgrade soils[J].Journal of Geotechnical Engineering,1996,122(12):1006-1013.
[11]Chai Jinchun,Miura N.Traffic-load-induced permanent deformation of road on soft subsoil[J].Journal of Geotechnical and Geoenvironmental Engineering,2002,128(11):507-916.
[12]翟婉明.车辆-轨道耦合动力学[M].北京:科学出版社,2007.ZHAI Wanming.Vehicle-track coupling dynamics[M].Beijing:Science Press,2007.
[13]Chai J C,Miura N.Traffic-load-induced permanent deformation of road on soft subsoil[J].Journal of Geotechnical Engineering Division,American Society of Civil Engineering,2002,128(11):907-916.
[14]张建明,刘端,齐吉琳.青藏铁路冻土路基沉降变形预测[J].中国铁道科学,2007,28(3):12-17.ZHANG Jianming,LIU Duan,QI Jilin.Estimation on the settlement and deformation of embankment along Qinghai-Tibet Railway in permafrost regions[J].China Railway Science,2007,28(3):12–17.
[15]蔡袁强,于玉贞,袁晓铭,等.土动力学与岩土地震工程[J].土木工程学报,2016,49(5):9-30.CAI Yuanqiang,YU Yuzhen,YUAN Xiaoming,et al.Soil dynamics and geotechnical earthquake engineering[J].China Civil Engineering Journal,2016,49(5):9-30.
[16]车爱兰,岩檐敞广,葛修润.关于地铁地震响应的模型振动试验及数值分析[J].岩土力学,2006,27(8):1293-1298.CHE Ailan,IWATATE Takahiro,GE Xiurun.Dynamic behaviors of subway structure subjected to strong earthquake motions using shaking table tests and dynamic analyses[J].Rock and Soil Mechanics,2006,27(8):1293-1298.
[17]朱占元.青藏铁路列车行驶多年冻土场地路基振动反应与振陷预测[D].哈尔滨:哈尔滨工业大学,2009.ZHU Zhanyuan.Train-induced vibration response and subsidence prediction of permafrost subgrade along Qinghai-Tibet Railway[D].Harbin:Harbin Institute of Technology,2009.
[18]陈拓,吴志坚,车爱兰.机车动荷载作用下多年冻土区铁路路基动力响应的试验研究[J].地震工程与工程振动,2011,31(1):168-173.CHEN Tuo,WU Zhijian,CHE Ailan.Test study on dynamic responses of railroad embankments in permafrost regions under train dynamic loading[J].Journal of Earthquake Engineering and Engineering Vibration,2011,31(1):168-173.
[19]LI Dingqing,Selig E T.Method for railroad track foundation design(Ⅰ):development[J].Journal of Geotechnical and Geoenviromental Engineering,1998,124(4):316-322.
[20]LI Dingqing,Selig E T.Method for railroad track foundation design(Ⅱ):application[J].Journal of Geotechnical and Geoenviromental Engineering,1998,124(4):323-329.
[21]边学成,曾二贤,陈云敏.列车交通荷载作用下软土路基的长期沉降[J].岩土力学,2008,29(11):2990-2996.BIAN Xuecheng,ZENG Erxian,CHEN Yunmin.Long-term settlements of soft soil ground induced by train traffic loadings[J].Rock and Soil Mechanics,2008,29(11):2990-2996.
[22]董亮.高速铁路路基动力特性及列车循环荷载作用下变形性质研究[D].北京:北京交通大学,2008.DONG Liang.Dynamic response and cumulative deformation for high-speed railway subgrade due to moving loads[D].Beijing:Beijing Jiaotong University,2008.
[23]焦贵德,赵淑萍,马巍.冻融循环后高温冻结粉土在循环荷载下的动力特性试验研究[J].土木工程学报,2010,43(12):107-113.JIAO Guide,ZHAO Shuping,MA Wei.Experimental study of the dynamic characteristics of warm-frozen silt after freeze-thaw cycles under cyclic loading[J].China Civil Engineering Journal,2010,43(12):107-113.