地震扰动下边坡的浅表动力效应与锚固控制机理试验研究
|
摘要
针对汶川震区国道213线都江堰-映秀段道路边坡崩滑和岩土损伤深度所表现的地震扰动浅表动力效应现象,通过大型振动台模型试验,对浅表效应产生机理及防护工程锚固控制机制进行了初步研究。试验采用高2.1m的砂粘土单面坡模型和3种地震波形,定量分析对比了0.253g、0.471g强震作用下3种典型高度原型边坡坡表与坡体内部的加速度放大率、动应变、振动主频等动力学响应量。由试验结果知,坡表的加速度放大率和振动主频平均较同高程坡体内部约大40%和45%,坡表的动剪应变及其与坡体内部间的动拉压应变量值显著,0.471g地震下峰值甚至高达6.5×10-3和2.2×10-3,均接近土体的极限应变。边坡浅表动力效应体现于浅表层与坡体内部间的不协调运动,拉-压动应变将产生剥离拉应力;同时与浅表层岩土动剪应变的反复揉搓作用相叠加,浅表层损伤积累及触发崩滑。对此,进一步通过锚固边坡与自然边坡的振动台模型试验对比,初步探讨了浅表动力效应的锚固控制机理,发现锚固结构能有效抑制坡表的加速度放大,提高坡体自振频率,试验中锚固边坡坡顶处加速度放大率较自然边坡小约15%～35%,自振频率提高近39%。分析锚固控制机理得:锚固后坡表自振频率提高,减轻地震波激励下的共振作用;锚固结构穿过浅层损伤破坏面将坡体内部与坡表连成整体,消除两者的不协调运动;锚固力抵消地震波在坡表反射造成的拉裂。论文研究可为汶川震区震后次生崩滑物源条件分析及边坡灾害防范深度提供一定的参考。
By means of a series of large-scale shaking model tests,the mechanism of side slope's superficial dynamic effect under earthquake disturbance and its anchoring prevention were experimentally studied to the typical pattern of small collapse-slide and shallow soil damage along Dujiangyan to Yingxiu section of national highway No.213 in Wenchuan earthquake region.Using a 2.1 m height single-side model slope built by sand blended with clay and excited by three typical earthquake waves of 0.253g and 0.471g accelerations separately,the different quantitative dynamic response characteristics between the superficial and deep position of slope body were analyzed comparatively.These response analysis included magnification factors of acceleration,dynamic strain value and predominant frequency corresponding with three height prototype single-side slopes of 2.1 m,10.7 m and 21.5 m.The result showed that the accelerate response of slope body's surface was approximately 1.4 times of the deep position averagely,and predominant frequency of vibration was increased around 45 percent accordingly.In particularly,it presented significant dynamic shear strain of superficial stratum and dynamic tension-compression strain between the superficial and deep position,which reached 6.5 × 10-3 and 2.2 × 10-3 respectively and averages about soil's failure limit strain.Due to the stress superposition of the stripping action conducted by tension-compression strain of incompatible response movement between superficial and deep position and the kneading action deduced by shear strain,slope's superficial failure or damage were occurred.Furthermore,with comparative shaking table model tests between anchored slope and natural slope,the mechanism of superficial failure prevention effect of anchoring structures was preliminary studied.It was found that,anchoring structures could remarkably reduce superficial accelerate response by about 15 to 35 percent and increase natural frequency by 39 percent compared with the original natural slope at slope top in experiments.Anchoring prevention mechanism included as follows:firstly,earthquake resonant interaction was reduced due to higher natural frequency of anchored slope;secondly,the incompatible movement was diminished by anchoring structures which joined the slope's superficial and deep position into a whole;thirdly,stripping action induced by stress wave reflection on slope's surface was counteracted by the anchoring force.These results can provide references for road reconstruction and hazards prevention after earthquake.
By means of a series of large-scale shaking model tests,the mechanism of side slope's superficial dynamic effect under earthquake disturbance and its anchoring prevention were experimentally studied to the typical pattern of small collapse-slide and shallow soil damage along Dujiangyan to Yingxiu section of national highway No.213 in Wenchuan earthquake region.Using a 2.1 m height single-side model slope built by sand blended with clay and excited by three typical earthquake waves of 0.253g and 0.471g accelerations separately,the different quantitative dynamic response characteristics between the superficial and deep position of slope body were analyzed comparatively.These response analysis included magnification factors of acceleration,dynamic strain value and predominant frequency corresponding with three height prototype single-side slopes of 2.1 m,10.7 m and 21.5 m.The result showed that the accelerate response of slope body's surface was approximately 1.4 times of the deep position averagely,and predominant frequency of vibration was increased around 45 percent accordingly.In particularly,it presented significant dynamic shear strain of superficial stratum and dynamic tension-compression strain between the superficial and deep position,which reached 6.5 × 10-3 and 2.2 × 10-3 respectively and averages about soil's failure limit strain.Due to the stress superposition of the stripping action conducted by tension-compression strain of incompatible response movement between superficial and deep position and the kneading action deduced by shear strain,slope's superficial failure or damage were occurred.Furthermore,with comparative shaking table model tests between anchored slope and natural slope,the mechanism of superficial failure prevention effect of anchoring structures was preliminary studied.It was found that,anchoring structures could remarkably reduce superficial accelerate response by about 15 to 35 percent and increase natural frequency by 39 percent compared with the original natural slope at slope top in experiments.Anchoring prevention mechanism included as follows:firstly,earthquake resonant interaction was reduced due to higher natural frequency of anchored slope;secondly,the incompatible movement was diminished by anchoring structures which joined the slope's superficial and deep position into a whole;thirdly,stripping action induced by stress wave reflection on slope's surface was counteracted by the anchoring force.These results can provide references for road reconstruction and hazards prevention after earthquake.
引文
[1]Huang Runqiu.Mechanism and geomechanical modes of landslide hazards triggered by Wenchuan8.0 earthquake [J].Chinese Journal of Rock Mechanics and Engineering,2009,28(6):1239-1249.[黄润秋.汶川8.0级地震触发崩滑灾害机制及其地质力学模式[J].岩石力学与工程学报,2009,28(6):1239-1249.]
[2]Huang Runqiu,Li Weile.Research on development and distribution rules of geohazards induced by Wenchuan earthquake on 12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592.[黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592.]
[3]Huang Runqiu,Pei Xiangjun,Li Tianbin.Basic characteristics and formation mechanism of the largest scale landslide at Daguangbao occurred during the Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):730-741.[黄润秋,裴向军,李天斌.汶川地震触发大光包巨型滑坡基本特征及形成机理分析[J].工程地质学报,2008,16(6):730-741.]
[4]Zhuang Jianqi,Cui Peng,Ge Yonggang,et al.Distribution characteristics and impact factors assessment of collapses and landslides caused by 5.12 Wenchuan earthquake:taking Dujiangyan-Wenchuan highway as a sample[J].Geological Science and Technology Information,2009,28(2):16-22.[庄建琦,崔鹏,葛永刚,等.5.12汶川地震崩塌滑坡分布特征及影响因子评价——以都江堰至汶川公路沿线为例[J].地质科技情报,2009,28(2):16-22.]
[5]Liu Chunling,Qi Shengwen,Tong Liqiang,et al.Stability analysis of slope under earthquake with FLAC3D[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(16):2730-2733.[刘春玲,祁生文,童立强,等.利用FLAC3D分析某边坡地震稳定性[J].岩石力学与工程学报,2004,23(16):2730-2733.]
[6]Feng Wenkai,Xu Qiang,Huang Runqiu.Preliminary study on mechanical mechanism of slope earthquake-induced deformation[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(S1):3124-3130.[冯文凯,许强,黄润秋.斜坡震裂变形力学机制初探[J].岩石力学与工程学报,2009,28(S1):3124-3130.]
[7]祁生文,伍法权,严福章,等.岩质边坡动力反应分析[M].北京:科学出版社,2007:30-65.
[8]Liu Hongshuai,Bo Jingshan,Liu Dedong.Review on study of seismic stability analysis of rock-soil slopes[J].Earthquake Engineering and Engineering Vibration,2005,25(1):164-171.[刘红帅,薄景山,刘德东.岩土边坡地震稳定性分析研究评述[J].地震工程与工程振动,2005,25(1):164-171.]
[9]Yu Yuzhen,Deng Lijun,Li Rongjian.Centrifuge model test of the seismic response behavior of a sand slope[J].Journal of Tsinghua University:Sci&Tech,2007,47(6):789-792.[于玉贞,邓丽军,李荣建.砂土边坡地震动力响应离心模型试验[J].清华大学学报:自然科学版,2007,47(6):789-792.]
[10]Lin Meeiling,Wang Kuolung.Seismic slope behavior in a large-scale shaking table model test[J].Engineering Geology,2006,86(2):118-133.
[11]Xu Guangxing,Yao Lingkan,Gao Zhaoning,et al.Large-scale shaking table model test study on dynamic characteristics and dynamic responses of slope[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):624-632.[徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624-632.]
[12]Jiang Liangwei,Yao Lingkan,Wang Jian.Similitude for shaking table model test on side slope relating to dynamic characteristics and strength[J].Journal of Transport Science and Engineering,2009,25(2):1-7[蒋良潍,姚令侃,王建.基于振动性态和破坏相似的边坡振动台模型实验相似律[J].交通科学与工程,2009,25(2):1-7]
[13]Jiang Liangwei,Yao Lingkan,Wu Wei.Study on calculation of dynamic displacement from time integration of acceleration in shaking table model tests of side slope[J].Journal of Disaster Prevention and Mitigation Engineering,2009,29(3):261-266.[蒋良潍,姚令侃,吴伟.边坡振动台模型实验动位移的加速度时程积分探讨[J].防灾减灾工程学报,2009,29(3):261-266.]
[14]Jiang Liangwei,Yao Lingkan,Wu Wei,et al.Transfer function analysis of earthquake simulation shaking table model test of side slopes[J].Rock and Soil Mechanics,2010,31(5):1368-1374.[蒋良潍,姚令侃,吴伟,等.传递函数分析在边坡振动台模型试验的应用探讨[J].岩土力学,2010,31(5):1368-1374.]
[15]单娜琳,程志平,刘云赖.工程地震勘探[M].北京:冶金工业出版社,2006.122-145.
[16]赵明阶,黄卫东,韦刚.公路土石混填路基压实度波动检测技术及应用[M].北京:人民交通出版社,2006:110-113.
[17]Xu Guangxing,Yao Lingkan,Li Zhaohong,et al.Dynamic response of slopes under earthquakes and influence of ground motion parameters[J].Chinese Journal of Geotechnical Engineering,2008,30(6):918-923.[徐光兴,姚令侃,李朝红,等.边坡地震动力响应规律及地震动参数影响研究[J].岩土工程学报,2008,30(6):918-923.]
[18]张克绪,谢君斐.土动力学[M].北京:地震出版社,1989:30-36.
[19]陈国兴.岩土地震工程学[M].北京:科学出版社,2007:152-167.
[20]Li Lei,Rong Weidong.Experimental study on limit tensile strain under bending of compacted soil[J].Journal of Nanjing hydraulic research institute,2000(1):43-48.[李雷,荣卫东.几种击实土挠曲极限拉应变的试验研究[J].水利水运科学研究,2000(1):43-48.]
[21]廖振鹏.工程波动理论导论[M].北京:科学出版社,2002:44-48.
[22]Xu Longjun,Xie Lili.Characteristics of acceleration response spectra for vertical ground motions[J].Journal of Earthquake Engineering and Engineering Vibration,2007,27(6):17-23.[徐龙军,谢礼立.竖向地震动加速度反应谱特性[J].地震工程与工程振动,2007,27(6):17-23.]
[23]Wang Zehua,Yan Peng.The cause of Wenchuan Earthquake and the analysis of seismic dynamic characteristic[J].Sichuan Building Science,2010,36(1):155-159.[王泽华,严鹏.汶川地震产生原因及其地震动特性分析[J].四川建筑科学研究,2010,36(1):155-159.]
[24]Yao Lingkan,Chen Qiang.New research subjects on earthquake resistant techniques of line engineering extracted from“5.12”Wenchuan Earthquake[J].Journal of Sichuan University:Engineering Science Edition,2009,41(3):43-50.[姚令侃,陈强.“5.12”汶川地震对线路工程抗震技术提出的新课题[J].四川大学学报:工程科学版,2009,41(3):43-50.]
[25]王国隆,林美聆,林圣琪.921集集大地震后续的坡地灾害[J].地质(中国台湾地区出版发行),2009,28(3):54-59.
[2]Huang Runqiu,Li Weile.Research on development and distribution rules of geohazards induced by Wenchuan earthquake on 12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592.[黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592.]
[3]Huang Runqiu,Pei Xiangjun,Li Tianbin.Basic characteristics and formation mechanism of the largest scale landslide at Daguangbao occurred during the Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):730-741.[黄润秋,裴向军,李天斌.汶川地震触发大光包巨型滑坡基本特征及形成机理分析[J].工程地质学报,2008,16(6):730-741.]
[4]Zhuang Jianqi,Cui Peng,Ge Yonggang,et al.Distribution characteristics and impact factors assessment of collapses and landslides caused by 5.12 Wenchuan earthquake:taking Dujiangyan-Wenchuan highway as a sample[J].Geological Science and Technology Information,2009,28(2):16-22.[庄建琦,崔鹏,葛永刚,等.5.12汶川地震崩塌滑坡分布特征及影响因子评价——以都江堰至汶川公路沿线为例[J].地质科技情报,2009,28(2):16-22.]
[5]Liu Chunling,Qi Shengwen,Tong Liqiang,et al.Stability analysis of slope under earthquake with FLAC3D[J].Chinese Journal of Rock Mechanics and Engineering,2004,23(16):2730-2733.[刘春玲,祁生文,童立强,等.利用FLAC3D分析某边坡地震稳定性[J].岩石力学与工程学报,2004,23(16):2730-2733.]
[6]Feng Wenkai,Xu Qiang,Huang Runqiu.Preliminary study on mechanical mechanism of slope earthquake-induced deformation[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(S1):3124-3130.[冯文凯,许强,黄润秋.斜坡震裂变形力学机制初探[J].岩石力学与工程学报,2009,28(S1):3124-3130.]
[7]祁生文,伍法权,严福章,等.岩质边坡动力反应分析[M].北京:科学出版社,2007:30-65.
[8]Liu Hongshuai,Bo Jingshan,Liu Dedong.Review on study of seismic stability analysis of rock-soil slopes[J].Earthquake Engineering and Engineering Vibration,2005,25(1):164-171.[刘红帅,薄景山,刘德东.岩土边坡地震稳定性分析研究评述[J].地震工程与工程振动,2005,25(1):164-171.]
[9]Yu Yuzhen,Deng Lijun,Li Rongjian.Centrifuge model test of the seismic response behavior of a sand slope[J].Journal of Tsinghua University:Sci&Tech,2007,47(6):789-792.[于玉贞,邓丽军,李荣建.砂土边坡地震动力响应离心模型试验[J].清华大学学报:自然科学版,2007,47(6):789-792.]
[10]Lin Meeiling,Wang Kuolung.Seismic slope behavior in a large-scale shaking table model test[J].Engineering Geology,2006,86(2):118-133.
[11]Xu Guangxing,Yao Lingkan,Gao Zhaoning,et al.Large-scale shaking table model test study on dynamic characteristics and dynamic responses of slope[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(3):624-632.[徐光兴,姚令侃,高召宁,等.边坡动力特性与动力响应的大型振动台模型试验研究[J].岩石力学与工程学报,2008,27(3):624-632.]
[12]Jiang Liangwei,Yao Lingkan,Wang Jian.Similitude for shaking table model test on side slope relating to dynamic characteristics and strength[J].Journal of Transport Science and Engineering,2009,25(2):1-7[蒋良潍,姚令侃,王建.基于振动性态和破坏相似的边坡振动台模型实验相似律[J].交通科学与工程,2009,25(2):1-7]
[13]Jiang Liangwei,Yao Lingkan,Wu Wei.Study on calculation of dynamic displacement from time integration of acceleration in shaking table model tests of side slope[J].Journal of Disaster Prevention and Mitigation Engineering,2009,29(3):261-266.[蒋良潍,姚令侃,吴伟.边坡振动台模型实验动位移的加速度时程积分探讨[J].防灾减灾工程学报,2009,29(3):261-266.]
[14]Jiang Liangwei,Yao Lingkan,Wu Wei,et al.Transfer function analysis of earthquake simulation shaking table model test of side slopes[J].Rock and Soil Mechanics,2010,31(5):1368-1374.[蒋良潍,姚令侃,吴伟,等.传递函数分析在边坡振动台模型试验的应用探讨[J].岩土力学,2010,31(5):1368-1374.]
[15]单娜琳,程志平,刘云赖.工程地震勘探[M].北京:冶金工业出版社,2006.122-145.
[16]赵明阶,黄卫东,韦刚.公路土石混填路基压实度波动检测技术及应用[M].北京:人民交通出版社,2006:110-113.
[17]Xu Guangxing,Yao Lingkan,Li Zhaohong,et al.Dynamic response of slopes under earthquakes and influence of ground motion parameters[J].Chinese Journal of Geotechnical Engineering,2008,30(6):918-923.[徐光兴,姚令侃,李朝红,等.边坡地震动力响应规律及地震动参数影响研究[J].岩土工程学报,2008,30(6):918-923.]
[18]张克绪,谢君斐.土动力学[M].北京:地震出版社,1989:30-36.
[19]陈国兴.岩土地震工程学[M].北京:科学出版社,2007:152-167.
[20]Li Lei,Rong Weidong.Experimental study on limit tensile strain under bending of compacted soil[J].Journal of Nanjing hydraulic research institute,2000(1):43-48.[李雷,荣卫东.几种击实土挠曲极限拉应变的试验研究[J].水利水运科学研究,2000(1):43-48.]
[21]廖振鹏.工程波动理论导论[M].北京:科学出版社,2002:44-48.
[22]Xu Longjun,Xie Lili.Characteristics of acceleration response spectra for vertical ground motions[J].Journal of Earthquake Engineering and Engineering Vibration,2007,27(6):17-23.[徐龙军,谢礼立.竖向地震动加速度反应谱特性[J].地震工程与工程振动,2007,27(6):17-23.]
[23]Wang Zehua,Yan Peng.The cause of Wenchuan Earthquake and the analysis of seismic dynamic characteristic[J].Sichuan Building Science,2010,36(1):155-159.[王泽华,严鹏.汶川地震产生原因及其地震动特性分析[J].四川建筑科学研究,2010,36(1):155-159.]
[24]Yao Lingkan,Chen Qiang.New research subjects on earthquake resistant techniques of line engineering extracted from“5.12”Wenchuan Earthquake[J].Journal of Sichuan University:Engineering Science Edition,2009,41(3):43-50.[姚令侃,陈强.“5.12”汶川地震对线路工程抗震技术提出的新课题[J].四川大学学报:工程科学版,2009,41(3):43-50.]
[25]王国隆,林美聆,林圣琪.921集集大地震后续的坡地灾害[J].地质(中国台湾地区出版发行),2009,28(3):54-59.
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