饱和软土自由场地地震反应特性振动台试验
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摘要
为了解软土自由场地地震反应特性,开展饱和软土自由场地地震反应特性大型振动台模型试验。分别从模型体系自振特性、震陷位移及不同土层深度测点的加速度、动孔压比等动力响应指标方面,较为深入和全面地分析饱和软土自由场地地震反应规律、破坏机理。同时还分析模型箱的"边界效应"以验证试验土箱的合理性、有效性和测试仪器性能,并由此进一步确定模型地基有效工作区域。研究表明:(1)地震动作用下,饱和软土自由场地特征频率降低,阻尼增大;(2)饱和软土自由场地对水平输入地震波具有短周期滤波、长周期放大效应,且强震作用下地基失效并表现为减隔震作用;(3)饱和软土自由场地动孔压比优势区域位于浅埋土层,并随着输入地震动强度的增大,该区域动孔压比优势逐渐减弱。该研究可为非自由软土场地试验研究提供必要的技术经验。
This work investigated the seismic response characteristics of a free field in soft soil through a large-scale shaking table test. The seismic response characteristics and failure mechanism of the soft-soil free field were studied from several aspects, i.e., the natural vibration characteristics and subsidence displacement of the model system and the acceleration and dynamic pore pressure ratio of measurement points at different soil depths. The boundary effect of the laminar shear model box was also analyzed to verify the rationality and effectiveness of the soil box system and to test instrument performance. The effective working area of the model foundation was then further determined. Study results showed the following:(1) The characteristic frequency of the saturated soft-soil free field decreased and the damping ratio increased under seismic load.(2) The saturated soft-soil free field exerted short-term filtering and long-term amplification effects on horizontal input seismic waves. Moreover, under strong seismic loads, the failure foundation absorbed and isolated shock.(3) The peak pore pressure ratio of the saturated soft-soil free field was located in a shallow buried soil layer. The advantage of dynamic pore pressure ratio in this area gradually weakened as the input ground motion intensity increased. This research can provide the necessary technical experience for experimental studies on non-free-field soft soil.
This work investigated the seismic response characteristics of a free field in soft soil through a large-scale shaking table test. The seismic response characteristics and failure mechanism of the soft-soil free field were studied from several aspects, i.e., the natural vibration characteristics and subsidence displacement of the model system and the acceleration and dynamic pore pressure ratio of measurement points at different soil depths. The boundary effect of the laminar shear model box was also analyzed to verify the rationality and effectiveness of the soil box system and to test instrument performance. The effective working area of the model foundation was then further determined. Study results showed the following:(1) The characteristic frequency of the saturated soft-soil free field decreased and the damping ratio increased under seismic load.(2) The saturated soft-soil free field exerted short-term filtering and long-term amplification effects on horizontal input seismic waves. Moreover, under strong seismic loads, the failure foundation absorbed and isolated shock.(3) The peak pore pressure ratio of the saturated soft-soil free field was located in a shallow buried soil layer. The advantage of dynamic pore pressure ratio in this area gradually weakened as the input ground motion intensity increased. This research can provide the necessary technical experience for experimental studies on non-free-field soft soil.
引文
[1] 陈国兴,陈苏,杜修力,等.城市地下结构抗震研究进展[J].防灾减灾工程学报,2016,36(1):1-23.CHEN Guoxing,CHEN Su,DU Xiuli,et al.Review of Seismicdamage,Model Test,Available Design and Analysis Methods of Urban Underground Structures:Retrospect and Prospect[J].Journal of Disaster Prevention and Mitigation Engineering,2016,36(1):1-23.
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[6] 蒋录珍,李双飞,石文倩,等.饱和土体-地下综合管廊结构地震响应分析[J].地震工程学报,2018,40(6):1224-1230.JIANG Luzhen,LI Shuangfei,SHI Wenqian,et al.Seismic Response of Underground Utility Tunnel Structures in Saturated Soils[J].China Earthquake Engineering Journal,2018,40(6):1224-1230.
[7] 王国波.软土地铁车站结构三维地震响应计算理论与方法的研究[D].上海:同济大学,2007.WANG Guobo.Study on Calculation Theory and Method of Three Dimensional Seismic Response of Subway Station Structures in Soft Soil[J].Shanghai:Tongji University,2007.
[8] 伍小平,孙利民,胡世德,等.振动台试验用层状剪切变形土箱的研制[J].同济大学学报,2002,30(7):781-785.WU Xiaoping,SUN Limin,HU Shide,et al.Development of Laminar Shear Box Used in Shaking Table Test[J].Journal of TongjiUninvrsity,2002,30(7):781-785.
[9] 苏栋,李相菘.离心机自由场地震响应的完全耦合模拟[J].岩土力学,2006,27(10):1079-1085.SU Dong,LI Xiangsong.Fully Coupled Simulation of Seismic Ground Response at Centrifuge[J].Rock and Soil Mechanics,2006,27(10):1079-1085.
[10] 王国波,杨林德,季倩倩.上海软土地震响应的振动台模型试验及其三维数值模拟分析[J].西北地震学报,2008,30(1):27-30.WANG Guobo,YANG Linde,JI Qianqian.The Shaking Table Model Test of Seismic Response for Shanghai Soft Soil and Three Dimensional Numerical Fitting Analysis[J].Northwestearn Seismologgical Journal,2008,30(1):27-30.
[11] 吕西林,任红梅,李培振,等.液化场地自由场体系的数值分析及振动台试验验证[J].岩石力学与工程学报,2009,28(增刊2):4046-4053.Lü Xilin,REN Hongmei,LI Peizhen,et al.Numerical Analysis of Free Field System in Liquefiable Site and Vailidation of Shaleing Table Tests[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp2):4046-4053.
[12] 李培振,崔圣龙,吕西林,等.液化地基自由场振动台试验的土性参数识别[J].同济大学学报(自然科学版),2010,38(6):791-797.LI Peizhen,CUI Shenglong,Lü Xilin,et al.Parameter Identification of Liquefiable Soil in Free Field Tested on Shaking Table[J].Journal of Tongji University (Natural Science),2010,38(6):791-797.
[13] 李培振,任红梅,吕西林,等.液化地基自由场振动台模型试验研究[J].地震工程与工程振动,2008,28(2):171-177.LI Peizhen,REN Hongmei,Lü Xilin,et al.Shaking Table Test on Free Field Considering Soil Liquefaction[J].Journal of Earthquake Engineering and Engineering Vibration,2008,28(2):171-177.
[14] 高广运,陈青生,何俊锋,等.地下水位上升对上海软土场地地震反应的影响[J].岩土工程学报,2011,33(7):989-995.GAO Guangyun,CHEN Qingsheng,HE Junfeng,et al.Effect of Rise of Groundwater Table on Seismic Ground Response of Soft Soil in Shanghai[J].Chinese Journal of Geotechnical Engineering,2011,33(7):989-995.
[15] CHEN Q S,YANG J,GAO G Y.Dynamic Response of Deep Soft Soil Deposits under Multidirectional Earthquake Loading[J].Engineering Geology,2011,121(1):55-65.
[16] 陈青生,高广运,何俊锋.上海软土场地三维非线性地震反应分析[J].岩土力学,2011,32(11):3461-3467.CHEN Qingsheng,GAO Guangyun,HE Junfeng.Three-dimensional Nonlinear Analysis of Seismic Ground Response of Soft Soils in Shanghai[J].Rock and Soil Mechanics,2011,32(11):3461-3467.
[17] ZHUANG H Y,HU Z H,CHEN G X.Numerical Modeling on the Seismic Responses of a Large Underground Structure in Soft Ground[J].Chinese Journal of Vibroengineering,2015,17(2):802-815.
[18] 崔春义,孟坤,梁志孟,等.深圳老街地铁车站自由场地地震动力特性数值分析[J].沈阳建筑大学学报(自然科学版),2016,32(6):1008-1016.CUI Chunyi,MENG Kun,LIANG Zhimeng,et al.Seismic Numerical Analyses of Free Field around Shenzhen-Laojie Subway Station[J].Journal of Shenyang Jianzhu University (Natural Science),2016,32(6):1008-1016.
[19] 程学磊,崔春义,孙宗光,等.饱和软土自由场振动台试验与数值模拟对比[J].大连海事大学学报,2018,44(3):88-95.CHENG Xuelei,CUI Chunyi,SUN Zongguang,et al.Comparison Between Large-Size Shaking Table Test and Numerical Simulation for Free Field of Saturated Soft Soil[J].Journal of Dalian Maritime University,2018,44(3):88-95.
[20] CHEN G X,CHEN S,ZUO X,et al.Shaking-table Tests and Numerical Simulations on a Subway Structure in Soft Soil[J].Soil Dynamics and Earthquake Engineering,2015,76:13-28.
[21] CHEN G X,CHEN S,DU X L,et al.Shaking Table Tests on a Three-Arch Type Subway Station Structure in a Liquefiablesoil[J].Bulletin of Earthquake Engineering,2015,13(6):1675-1701.
[22] MOGHADM M R,BAZIAR M H.Seismic Ground Motion Amplification Pattern Induced by a Subway Tunnel:Shaking Table Testing and Numerical Simulation[J].Soil Dynamics and Earthquake Engineering,2016,83:81-97.
[23] 李雨润,强东峰,邹泽,等.不同厚度饱和砂土中群桩结构动力响应试验研究[J].地震工程学报,2018,40(4):625-630.LI Yurun,QIANG Dongfeng,ZOU Ze,et al.Experimental Study on the Dynamic Response of Pile-Group Structure in Saturated Sand with Different Thicknesses[J].China Earthquake Engineering Journal,2018,40(4):625-630.
[24] 田兆阳,李平,郑志华,等.软土动力特性动三轴试验研究[J].地震工程学报,2017,39(1):95-99.TIAN Zhaoyang,LI Ping,ZHENG Zhihua,et al.Dynamic Triaxial Tests on Dynamic Characteristics of Soft Soil[J].China Earthquake Engineering Journal,2017,39(1):95-99.
[25] 殷琳,楼梦麟,康帅,等.地下结构地震反应的振动台模型试验研究[J].同济大学学报(自然科学版),2015,43(10):1471-1479.YIN Lin,LOU Menglin,KANG Shuai,et al.Analysis of Shaking Table Test on Underground Structure[J].Journal of Tongji University (Natural Science),2015,43(10):1471-1479.
[2] 陈卫忠,宋万鹏,赵武胜,等.地下工程抗震分析方法及性能评价研究进展[J].岩石力学与工程学报,2017,36(2):310-325.CHEN Weizhong,SONG Wanpeng,ZHAO Wusheng,et al.Research Progress of Seismic Analysis Methods and Performance Evaluation in Underground Engineering[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(2):310-325.
[3] 杜修力,李洋,许成顺,等.1995年日本阪神地震大开地铁车站震害原因及成灾机理分析研究进展[J].岩土工程学报,2018,40(2):223-236.DU Xiuli,LI Yang,XU Chengshun,et al.Review on Damage Causes and Disaster Mechanism of Daikai Subway Station During 1995 Osaka-Kobe Earthquake[J].Chinese Journal of Geotechnical Engineering,2018,40(2):223-236.
[4] 袁林娟,刘小生,汪小刚,等.振动台土-箱结构模型动力特性及反应的解析分析[J].岩土工程学报,2012,34(6):1038-1042.YUAN Linjuan,LIU Xiaosheng,WANG Xiaogang,et al.Analytic Solution of Dynamic Characteristics and Responses of Soil-Box Model for Shaking Table Tests[J].Chinese Journal of Geotechnical Engineering,2012,34(6):1038-1042.
[5] 崔春义,程学磊,孙宗光,等.软基场地地铁车站地震响应及参数敏感性分析[J].铁道工程学报,2017,34(3):92-98,105.CUI Chunyi,CHENG Xuelei,SUN Zongguang,et al.Analysis of Seismic Response and Parametric Sensitivity of Subway Station Surrounded by Saturated Soft Soil[J].Journal of Railway Engineering Society,2017,34(3):92-98,105.
[6] 蒋录珍,李双飞,石文倩,等.饱和土体-地下综合管廊结构地震响应分析[J].地震工程学报,2018,40(6):1224-1230.JIANG Luzhen,LI Shuangfei,SHI Wenqian,et al.Seismic Response of Underground Utility Tunnel Structures in Saturated Soils[J].China Earthquake Engineering Journal,2018,40(6):1224-1230.
[7] 王国波.软土地铁车站结构三维地震响应计算理论与方法的研究[D].上海:同济大学,2007.WANG Guobo.Study on Calculation Theory and Method of Three Dimensional Seismic Response of Subway Station Structures in Soft Soil[J].Shanghai:Tongji University,2007.
[8] 伍小平,孙利民,胡世德,等.振动台试验用层状剪切变形土箱的研制[J].同济大学学报,2002,30(7):781-785.WU Xiaoping,SUN Limin,HU Shide,et al.Development of Laminar Shear Box Used in Shaking Table Test[J].Journal of TongjiUninvrsity,2002,30(7):781-785.
[9] 苏栋,李相菘.离心机自由场地震响应的完全耦合模拟[J].岩土力学,2006,27(10):1079-1085.SU Dong,LI Xiangsong.Fully Coupled Simulation of Seismic Ground Response at Centrifuge[J].Rock and Soil Mechanics,2006,27(10):1079-1085.
[10] 王国波,杨林德,季倩倩.上海软土地震响应的振动台模型试验及其三维数值模拟分析[J].西北地震学报,2008,30(1):27-30.WANG Guobo,YANG Linde,JI Qianqian.The Shaking Table Model Test of Seismic Response for Shanghai Soft Soil and Three Dimensional Numerical Fitting Analysis[J].Northwestearn Seismologgical Journal,2008,30(1):27-30.
[11] 吕西林,任红梅,李培振,等.液化场地自由场体系的数值分析及振动台试验验证[J].岩石力学与工程学报,2009,28(增刊2):4046-4053.Lü Xilin,REN Hongmei,LI Peizhen,et al.Numerical Analysis of Free Field System in Liquefiable Site and Vailidation of Shaleing Table Tests[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp2):4046-4053.
[12] 李培振,崔圣龙,吕西林,等.液化地基自由场振动台试验的土性参数识别[J].同济大学学报(自然科学版),2010,38(6):791-797.LI Peizhen,CUI Shenglong,Lü Xilin,et al.Parameter Identification of Liquefiable Soil in Free Field Tested on Shaking Table[J].Journal of Tongji University (Natural Science),2010,38(6):791-797.
[13] 李培振,任红梅,吕西林,等.液化地基自由场振动台模型试验研究[J].地震工程与工程振动,2008,28(2):171-177.LI Peizhen,REN Hongmei,Lü Xilin,et al.Shaking Table Test on Free Field Considering Soil Liquefaction[J].Journal of Earthquake Engineering and Engineering Vibration,2008,28(2):171-177.
[14] 高广运,陈青生,何俊锋,等.地下水位上升对上海软土场地地震反应的影响[J].岩土工程学报,2011,33(7):989-995.GAO Guangyun,CHEN Qingsheng,HE Junfeng,et al.Effect of Rise of Groundwater Table on Seismic Ground Response of Soft Soil in Shanghai[J].Chinese Journal of Geotechnical Engineering,2011,33(7):989-995.
[15] CHEN Q S,YANG J,GAO G Y.Dynamic Response of Deep Soft Soil Deposits under Multidirectional Earthquake Loading[J].Engineering Geology,2011,121(1):55-65.
[16] 陈青生,高广运,何俊锋.上海软土场地三维非线性地震反应分析[J].岩土力学,2011,32(11):3461-3467.CHEN Qingsheng,GAO Guangyun,HE Junfeng.Three-dimensional Nonlinear Analysis of Seismic Ground Response of Soft Soils in Shanghai[J].Rock and Soil Mechanics,2011,32(11):3461-3467.
[17] ZHUANG H Y,HU Z H,CHEN G X.Numerical Modeling on the Seismic Responses of a Large Underground Structure in Soft Ground[J].Chinese Journal of Vibroengineering,2015,17(2):802-815.
[18] 崔春义,孟坤,梁志孟,等.深圳老街地铁车站自由场地地震动力特性数值分析[J].沈阳建筑大学学报(自然科学版),2016,32(6):1008-1016.CUI Chunyi,MENG Kun,LIANG Zhimeng,et al.Seismic Numerical Analyses of Free Field around Shenzhen-Laojie Subway Station[J].Journal of Shenyang Jianzhu University (Natural Science),2016,32(6):1008-1016.
[19] 程学磊,崔春义,孙宗光,等.饱和软土自由场振动台试验与数值模拟对比[J].大连海事大学学报,2018,44(3):88-95.CHENG Xuelei,CUI Chunyi,SUN Zongguang,et al.Comparison Between Large-Size Shaking Table Test and Numerical Simulation for Free Field of Saturated Soft Soil[J].Journal of Dalian Maritime University,2018,44(3):88-95.
[20] CHEN G X,CHEN S,ZUO X,et al.Shaking-table Tests and Numerical Simulations on a Subway Structure in Soft Soil[J].Soil Dynamics and Earthquake Engineering,2015,76:13-28.
[21] CHEN G X,CHEN S,DU X L,et al.Shaking Table Tests on a Three-Arch Type Subway Station Structure in a Liquefiablesoil[J].Bulletin of Earthquake Engineering,2015,13(6):1675-1701.
[22] MOGHADM M R,BAZIAR M H.Seismic Ground Motion Amplification Pattern Induced by a Subway Tunnel:Shaking Table Testing and Numerical Simulation[J].Soil Dynamics and Earthquake Engineering,2016,83:81-97.
[23] 李雨润,强东峰,邹泽,等.不同厚度饱和砂土中群桩结构动力响应试验研究[J].地震工程学报,2018,40(4):625-630.LI Yurun,QIANG Dongfeng,ZOU Ze,et al.Experimental Study on the Dynamic Response of Pile-Group Structure in Saturated Sand with Different Thicknesses[J].China Earthquake Engineering Journal,2018,40(4):625-630.
[24] 田兆阳,李平,郑志华,等.软土动力特性动三轴试验研究[J].地震工程学报,2017,39(1):95-99.TIAN Zhaoyang,LI Ping,ZHENG Zhihua,et al.Dynamic Triaxial Tests on Dynamic Characteristics of Soft Soil[J].China Earthquake Engineering Journal,2017,39(1):95-99.
[25] 殷琳,楼梦麟,康帅,等.地下结构地震反应的振动台模型试验研究[J].同济大学学报(自然科学版),2015,43(10):1471-1479.YIN Lin,LOU Menglin,KANG Shuai,et al.Analysis of Shaking Table Test on Underground Structure[J].Journal of Tongji University (Natural Science),2015,43(10):1471-1479.