爆炸液化场地中浅埋钢筋混凝土结构动力响应的现场试验研究
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摘要
饱和砂土地基在爆炸荷载作用下会发生液化,地基上的结构物将受到爆炸荷载及地基液化的双重作用,从而产生不均匀沉降和破坏性变形。基于大型现场爆炸液化试验,对场地上钢筋混凝土(RC)结构的动力响应和地基液化后RC结构的变形进行了分析研究。结果表明:液化场地中浅埋RC结构产生了明显的不均匀沉降,且最大沉降量达到结构高度的10%,结构差异沉降达到最大沉降量的1/5,结构沉降变形在液化后15 h时基本稳定;RC结构表面未产生明显的裂缝,动态拉、压应变均在400??以内,不会对结构造成显著破坏;结构动力响应表现为柱侧加速度峰值明显大于梁侧,但柱侧动力稳定所需时间较梁侧短,即柱承受了更大的瞬时冲击力且其抵抗瞬时冲击力的能力更强。研究结果可以为在可液化地基中的浅埋RC结构稳定设计等工程情况提供参考。
Saturated sand foundation may be liquefied under explosive load. Structures on the foundation will suffer a dual influence of explosive load and sand liquefaction, which causes uneven settlement and destructive deformation. Based on a large-scale field test of liquefied foundation induced by embedded blast, the dynamic response of the shallow-buried reinforced concrete(RC) structures subjected to explosion and its deformations after liquefaction are examined. It is indicated that, obvious uneven settlement of the RC structure occurs; and the maximum settlement reaches 10% of the height of the RC structure; and differential settlement reaches 1/5 of the maximum settlement. The settlement comes to be stable in 15 hours after the explosion. There is no obvious crack appearing on the surface of the structure; and the dynamic tensile and compressive strains are both under 400 ??, which would not cause significant damage to the structure. The acceleration peak of the column is larger than that of the girder; however, the time required for the dynamic stability of column is shorter than that of the girder, i.e. column suffers a larger instantaneous impulse and has stronger ability to resist instantaneous impulse. The results provide references for the seismic design of shallow-buried RC structures in the liquefiable soils.
Saturated sand foundation may be liquefied under explosive load. Structures on the foundation will suffer a dual influence of explosive load and sand liquefaction, which causes uneven settlement and destructive deformation. Based on a large-scale field test of liquefied foundation induced by embedded blast, the dynamic response of the shallow-buried reinforced concrete(RC) structures subjected to explosion and its deformations after liquefaction are examined. It is indicated that, obvious uneven settlement of the RC structure occurs; and the maximum settlement reaches 10% of the height of the RC structure; and differential settlement reaches 1/5 of the maximum settlement. The settlement comes to be stable in 15 hours after the explosion. There is no obvious crack appearing on the surface of the structure; and the dynamic tensile and compressive strains are both under 400 ??, which would not cause significant damage to the structure. The acceleration peak of the column is larger than that of the girder; however, the time required for the dynamic stability of column is shorter than that of the girder, i.e. column suffers a larger instantaneous impulse and has stronger ability to resist instantaneous impulse. The results provide references for the seismic design of shallow-buried RC structures in the liquefiable soils.
引文
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[15]张建民,王刚.砂土液化后大变形的机制[J].岩土工程学报,2006,28(7):835-840.ZHANG Jian-min,WANG Gang.Mechanism of large post-liquefaction deformation in saturated sand[J].Chinese Journal of Geotechnical Engineering,2006,28(7):835-840.
[16]OKHOVAT M R,MAEKAWA K.Seismic performance of large underground structures in unsaturated and liquefiable soils[J].Lifeline Earthquake Engineering in a Multihazard Environment,ASCE,2009,357(41):424-435.
[17]WANG M W,IAI S,TOBITA T.Seismic performances of underground RC structures in liquefiable soils in nuclear plants[J].Ground Modification and Seismic Mitigation,ASCE,2006,(152):387-394.
[18]汪明武,Iai Susumu.地下RC结构物地震响应特征土工离心试验的模拟[J].地震工程与工程振动,2007,27(3):150-155.WANG Ming-wu,IAI SUSUMU.Numerical simulation of centrifuge modeling for seismic responses of underground RC structures[J].Earthquake Engineering and Engineering Vibration,2007,27(3):150-155.
[19]汪明武,李丽.液化场地浅埋钢筋混凝土结构物变形及动土压力分析[J].岩石力学与工程学报,2008,27(增刊2):3374-3379.WANG Ming-wu,LI Li.Analysis of deformations of shallow-buried reinforced concrete structures and dynamic earth pressures in liquefiable soils[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(Supp.2):3374-3379.
[20]汪明武,李丽.浅埋矩形RC结构物地震液化上浮有效应力分析[J].振动工程学报,2008,21(3):286-290.WANG Ming-wu,LI Li.Effective stress analysis of liquefaction-induced uplift of shallow duct-type underground RC structures[J].Journal of Vibration Engineering,2008,21(3):286-290.
[2]王明洋,国胜兵,赵跃堂,等.饱和砂土动力液化研究进展[J].解放军理工大学学报(自然科学版),2002,3(1):13-18.WANG Ming-yang,GUO Sheng-bing,ZHAO Yue-tang,et al.Progression of liquefaction investigation for saturated sand soil under dynamic loading[J].Journal of PLA University of Science and Technology,2002,3(1):13-18.
[3]LUCCIONI B M,AMBROSINI R D.Evaluating the effect of underground explosions on structures[J].Mecnica Computacional,2008,(25):1999-2019.
[4]辛凯,姜忻良,吴祥云.爆炸荷载作用下两相饱和土中结构响应试验研究[J].岩石力学与工程学报,2009,28(增刊2):4065-4070.XIN Kai,JIANG Xin-liang,WU Xiang-yun.Experimental study on structure response in two-phase saturated soil under blasting load[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.2):4065-4070.
[5]马立秋,张建民,胡耘,等.地面爆炸条件下浅埋地下结构物响应的离心模型试验研究[J].岩石力学与工程学报,2010,29(增刊2):3672-3678.MA Li-qiu,ZHANG Jian-min,HU Yun,et al.Centrifugal model tests for responses of shallow-buried underground structures under surface blasting[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Supp.2):3672-3678.
[6]穆朝民,齐娟,辛凯.高饱和度饱和土中爆炸波与结构的相互作用[J].岩土力学,2011,32(2):429-434.MU Chao-min,QI Juan,XIN Kai.Interaction between blast wave and structure in highly saturated soil[J].Rock and Soil Mechanics,2011,32(2):429-434.
[7]AL-QASIMI E A,CHARLIE W A,WOELLER D J.Canadian liquefaction experiment(CANLEX):blast-induced ground motion and pore pressure experiments[J].Geotechnical Testing Journal,2005,28(1):1-13.
[8]HIJIKATA K,ISHIDA T,TANAKA H,et al.Experimental study on soil-pile-structure interaction in liquefiable sand subjected to blast-induced ground[C]//Proceedings of 13th World Conference on Earthquake Engineering.Vancouver,B.C.,Canada:[s.n.],2004.
[9]ASHFORD S A,ROLLINS K M,LANE J D.Blastinduced liquefaction for full-scale foundation testing[J].Journal of Geotechnical and Geoenvironmental Engineering,ASCE,2004,130(8):798-806.
[10]燕琳,李世海,刘以纲.爆炸引起饱和砂地表沉降的试验研究[J].岩土工程学报,1998,20(3):50-53.YAN Lin,LI Shi-hai,LIU Yi-gang.A laboratory study on surface settlement of saturated sand caused by blasting[J].Chinese Journal of Geotechnical Engineering,1998,20(3):50-53.
[11]石玉成,王兰民,林学文.黄土场地的爆破地震振动效应[J].岩石力学与工程学报,2003,22(11):1933-1938.SHI Yu-cheng,WANG Lan-min,LIN Xue-wen.Effect of blast-induced ground motion in loess sites[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(11):1933-1938.
[12]张智超,陈育民,刘汉龙,等.孔隙水压力及炸药埋深对堤坝爆炸效应的影响分析[J].岩土力学,2012,33(7):2214-2220.ZHANG Zhi-chao,CHEN Yu-min,LIU Han-long,et al.Analysis of influences of pore water pressure and buried depth of explosive on blasting effect of embankments[J].Rock and Soil Mechanics,2012,33(7):2214-2220.
[13]张智超,陈育民,刘汉龙.微差爆破模拟天然地震的数值分析与效果评价[J].岩土力学,2013,34(1):265-274.ZHANG Zhi-chao,CHEN Yu-min,LIU Han-long.Numerical analysis and evaluation of simulation of nature earthquake by millisecond blasting technique[J].Rock and Soil Mechanics,2013,34(1):265-274.
[14]刘汉龙,周云东,高玉峰.砂土地震液化后大变形特性试验研究[J].岩土工程学报,2002,24(2):142-146.LIU Han-long,ZHOU Yun-dong,GAO Yu-feng.Study on the behavior of large ground displacement of sand due to seismic liquefaction[J].Chinese Journal of Geotechnical Engineering,2002,24(2):142-146.
[15]张建民,王刚.砂土液化后大变形的机制[J].岩土工程学报,2006,28(7):835-840.ZHANG Jian-min,WANG Gang.Mechanism of large post-liquefaction deformation in saturated sand[J].Chinese Journal of Geotechnical Engineering,2006,28(7):835-840.
[16]OKHOVAT M R,MAEKAWA K.Seismic performance of large underground structures in unsaturated and liquefiable soils[J].Lifeline Earthquake Engineering in a Multihazard Environment,ASCE,2009,357(41):424-435.
[17]WANG M W,IAI S,TOBITA T.Seismic performances of underground RC structures in liquefiable soils in nuclear plants[J].Ground Modification and Seismic Mitigation,ASCE,2006,(152):387-394.
[18]汪明武,Iai Susumu.地下RC结构物地震响应特征土工离心试验的模拟[J].地震工程与工程振动,2007,27(3):150-155.WANG Ming-wu,IAI SUSUMU.Numerical simulation of centrifuge modeling for seismic responses of underground RC structures[J].Earthquake Engineering and Engineering Vibration,2007,27(3):150-155.
[19]汪明武,李丽.液化场地浅埋钢筋混凝土结构物变形及动土压力分析[J].岩石力学与工程学报,2008,27(增刊2):3374-3379.WANG Ming-wu,LI Li.Analysis of deformations of shallow-buried reinforced concrete structures and dynamic earth pressures in liquefiable soils[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(Supp.2):3374-3379.
[20]汪明武,李丽.浅埋矩形RC结构物地震液化上浮有效应力分析[J].振动工程学报,2008,21(3):286-290.WANG Ming-wu,LI Li.Effective stress analysis of liquefaction-induced uplift of shallow duct-type underground RC structures[J].Journal of Vibration Engineering,2008,21(3):286-290.