隐伏逆冲断层上填方路基加固措施与变形破坏模式探究
|
摘要
试验路基以云贵铁路某填方路基为原型,试验路堤底部宽L=60 cm,路堤顶部宽l=10 cm,路堤高h=15 cm,采用室内模型试验研究了4组减震措施在逆冲断层作用下填方路基的变形响应。第1组是把路堤直接坐落在地基上,这组试验也是一组基本试验,其他试验组的试验结果可与该组试验结果进行对比;第2组是在路堤底部铺设一层土工格栅;第3组是在路堤中部和底部各铺设一层土工格栅;第4组是在路堤底部黏土层中打入预制的CFG桩,同时在路堤底部和中部各铺设一层土工格栅。试验中利用分离式位移计和百分表记录路堤的变形数据,通过对数据的处理分析研究路堤在不同加固措施下的变形破坏模式,研究结果表明:(1)在4组模型中,路基破坏主要是路堤本身产生了斜45°的裂缝;(2)在底部基岩错动量小于路堤高度13.6%时,路堤中加入两层土工格栅达到的减震效果最佳;当基岩错动量在路堤高度13.6%~20.5%之间时,CFG桩与路堤中加入两层土工格栅的减震措施最有效;(3)随着减震措施的加强,断层位移在地层中传播的角度变缓,影响范围加长,产生的震害程度降低了。研究结果对工程实践具有重要的指导意义。
The experimental subgrade is used to model a high embankment in the Yunnan-Guizhou Railway,which has a bottom width of L=60 cm,top width of l=10 cm,and height of h=15 cm.The experiment models are used to study the effect of four ground stabilizing measures(called four groups) on responses of the high embankment under the action of a thrust fault ruptures.Group 1 is the case that no ground stabilizing measure is taken and is a basic test.The results from the other three groups are all compared with that from group 1.Group 2 is the case that a layer of geogrid is laid at the bottom of the embankment,Group 3 is that two layers of geogrids are laid at the middle and bottom of the embankment respectively,and Group 4 is that CFG pile is used to stabilize the ground and two layers of geogrids are laid at the bottom and middle of the embankment respectively.Several displacement gauges and dials are used to record embankment deformation.Deformation and failure modes by caused by different stabilization measures are analyzed.Results show that:(1) In the 4 models,embankment damage is mainly caused by the crack of 45° in embankment.(2) When fault displacement is equal to or less than 13.6% of the embankment height,the engineering measure with two layers of geogrids has the best efficiency for reducing damage;when the fault displacement is greater than 13.6% of the embankment height and less than or equal to 20.5% of the embankment height,the measure with both CFG piles and two layers of geogrids can achieve the best efficiency.(3) Due to part of energy absorbed by soil foundation,failure angle in the ground gradually reduces as engineering measure gradually strengthens,as a result embankment damage extent is reduced because the length affected increases.The conclusions in the paper have significance for engineering practice.
The experimental subgrade is used to model a high embankment in the Yunnan-Guizhou Railway,which has a bottom width of L=60 cm,top width of l=10 cm,and height of h=15 cm.The experiment models are used to study the effect of four ground stabilizing measures(called four groups) on responses of the high embankment under the action of a thrust fault ruptures.Group 1 is the case that no ground stabilizing measure is taken and is a basic test.The results from the other three groups are all compared with that from group 1.Group 2 is the case that a layer of geogrid is laid at the bottom of the embankment,Group 3 is that two layers of geogrids are laid at the middle and bottom of the embankment respectively,and Group 4 is that CFG pile is used to stabilize the ground and two layers of geogrids are laid at the bottom and middle of the embankment respectively.Several displacement gauges and dials are used to record embankment deformation.Deformation and failure modes by caused by different stabilization measures are analyzed.Results show that:(1) In the 4 models,embankment damage is mainly caused by the crack of 45° in embankment.(2) When fault displacement is equal to or less than 13.6% of the embankment height,the engineering measure with two layers of geogrids has the best efficiency for reducing damage;when the fault displacement is greater than 13.6% of the embankment height and less than or equal to 20.5% of the embankment height,the measure with both CFG piles and two layers of geogrids can achieve the best efficiency.(3) Due to part of energy absorbed by soil foundation,failure angle in the ground gradually reduces as engineering measure gradually strengthens,as a result embankment damage extent is reduced because the length affected increases.The conclusions in the paper have significance for engineering practice.
引文
[1]ROTH W H,SCOTT R F,AUSTIN I.Numerical modeling of fault propagation in soils[J].Geophysical Research Letters,1981,8(6):561-564.
[2]郭恩栋,冯启民,薄景山,等.覆盖土层场地地震断裂试验[J].地震工程与工程振动,2001,21(3):145-149.GUO En-dong,FENG Qi-min,BAO Jing-shan,et al.Experiment of cover soil venue earthquake rupture[J].Earthquake Engineering and Engineering Vibration,2001,21(3):145-149.
[3]李小军.对近年大震震害现象与工程地震问题研究的思考[J].国际地震动态,2001,(8):26-31.LI Xiao-jun.Reflecting on the earthquake damage phenomena and engineering seismology of recent years[J].World Seismology,2001,(8):26-31.
[4]刘学增,朱合华.断层在土体中的传播模式及对地下管线的影响[[J].力学与实践,2004,26(5):7-13.LIU Xue-zeng,ZHU He-hua.The mode of propagation of the fault in the soil and the impact of underground pipeline[J].Mechanics and Practice,2004,26(5):7-13.
[5]徐锡伟,闻学泽,叶建青,等.2008汶川Ms8.0地震地表破裂及其发震构造[J].地震地质,30(3):597-629.XU Xi-wei,WEN Xue-ze,YE Jian-qing,et al.2008 Wenchuan Ms8.0 earthquake surface ruptures and its seismogenic structure[J].Seismology and Geology,30(3):597-629.
[6]BRAY J D,SEED R B.Earthquake fault rupture propagation through soil[J].Journal of Geotechnical Engineering,1994,120(3):543-561.
[7]刘学增,滨田政则.活断层破坏在土体中传播的实验研究[J].岩土工程学报,2004,26(3):425-427.LIU Xue-zeng,MASANORI Hamada.Experimental study of active fault damage spreading in the soil[J].Chinese Journal of Geotechnical Engineering,2004,26(3):425-427.
[8]徐锡伟,于贵华,马文涛,等.活断层地震地表破裂“避让带”宽度确定的依据与方法[J].地震地质,2002,24(4):470-483.XU Xi-wei,YU Gui-hua,MA Wen-tao,et al.The basis and method of determining the width of active fault earthquake surface rupture‘avoidance zone’[J].Seismology and Geology,2002,24(4):470-483.
[9]刘守华.地下断裂对不同土质上覆土层的工程影响[J].岩石力学与工程学报,2005,24(11):1868-1874.LIU Shou-hua.Influence of different overburden soils due to bedrock fracture[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(11):1868-1874.
[10]左熹,陈国兴.近远场地震动作用下地铁车站结构地基液化效应的振动台实验[J].岩土力学,2010,31(12):3733-3740.ZUO Xi,CHEN Guo-xing.Shaking table test on ground liquefaction effect of soil—metro station structure under near-and-far field ground motions[J].Rock and Soil Mechanics,2010,31(12):3733-3740.
[11]董云,何卫忠,孙蔚.隔堤填筑路堤的稳定性及变形破坏模式分析[J].岩土力学,2010,31(8):2471-2478.DONG Yun,HE Wei-zhong,SUN Wei.Analisis of stability&deformation mode of road embankment built aside dam[J].Rock and Soil Mechanics,2010,31(8):2471-2478.
[2]郭恩栋,冯启民,薄景山,等.覆盖土层场地地震断裂试验[J].地震工程与工程振动,2001,21(3):145-149.GUO En-dong,FENG Qi-min,BAO Jing-shan,et al.Experiment of cover soil venue earthquake rupture[J].Earthquake Engineering and Engineering Vibration,2001,21(3):145-149.
[3]李小军.对近年大震震害现象与工程地震问题研究的思考[J].国际地震动态,2001,(8):26-31.LI Xiao-jun.Reflecting on the earthquake damage phenomena and engineering seismology of recent years[J].World Seismology,2001,(8):26-31.
[4]刘学增,朱合华.断层在土体中的传播模式及对地下管线的影响[[J].力学与实践,2004,26(5):7-13.LIU Xue-zeng,ZHU He-hua.The mode of propagation of the fault in the soil and the impact of underground pipeline[J].Mechanics and Practice,2004,26(5):7-13.
[5]徐锡伟,闻学泽,叶建青,等.2008汶川Ms8.0地震地表破裂及其发震构造[J].地震地质,30(3):597-629.XU Xi-wei,WEN Xue-ze,YE Jian-qing,et al.2008 Wenchuan Ms8.0 earthquake surface ruptures and its seismogenic structure[J].Seismology and Geology,30(3):597-629.
[6]BRAY J D,SEED R B.Earthquake fault rupture propagation through soil[J].Journal of Geotechnical Engineering,1994,120(3):543-561.
[7]刘学增,滨田政则.活断层破坏在土体中传播的实验研究[J].岩土工程学报,2004,26(3):425-427.LIU Xue-zeng,MASANORI Hamada.Experimental study of active fault damage spreading in the soil[J].Chinese Journal of Geotechnical Engineering,2004,26(3):425-427.
[8]徐锡伟,于贵华,马文涛,等.活断层地震地表破裂“避让带”宽度确定的依据与方法[J].地震地质,2002,24(4):470-483.XU Xi-wei,YU Gui-hua,MA Wen-tao,et al.The basis and method of determining the width of active fault earthquake surface rupture‘avoidance zone’[J].Seismology and Geology,2002,24(4):470-483.
[9]刘守华.地下断裂对不同土质上覆土层的工程影响[J].岩石力学与工程学报,2005,24(11):1868-1874.LIU Shou-hua.Influence of different overburden soils due to bedrock fracture[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(11):1868-1874.
[10]左熹,陈国兴.近远场地震动作用下地铁车站结构地基液化效应的振动台实验[J].岩土力学,2010,31(12):3733-3740.ZUO Xi,CHEN Guo-xing.Shaking table test on ground liquefaction effect of soil—metro station structure under near-and-far field ground motions[J].Rock and Soil Mechanics,2010,31(12):3733-3740.
[11]董云,何卫忠,孙蔚.隔堤填筑路堤的稳定性及变形破坏模式分析[J].岩土力学,2010,31(8):2471-2478.DONG Yun,HE Wei-zhong,SUN Wei.Analisis of stability&deformation mode of road embankment built aside dam[J].Rock and Soil Mechanics,2010,31(8):2471-2478.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心