爆炸液化场地上堤坝变形的模型试验研究
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摘要
饱和砂土地基在地震、爆炸等振动荷载作用下易发生液化,从而使堤坝等上部构筑物发生破坏。开展了爆炸液化场地上堤坝变形的大型模型试验,考虑了筑坝材料以及堤坝地基加固措施对堤坝变形和坝身裂缝的影响。试验表明:堤坝沉降主要发生在场地液化后的1~2 h内,该段时间内产生的沉降占7 d时沉降量的84%~87%;掺加了碎石的堤坝比未加碎石的堤坝7 d时沉降量大24%;地基内采用土工格栅+土工布的加固措施能够有效减少堤坝在液化场地上的沉降,比未加固的堤坝沉降减少了10%。堤坝的裂缝主要出现在细骨料筑成的坝段和不同筑坝材料的交界处,沿坝身开展。总结了国内外规范中对于液化地基沉降的计算及预测方法,根据液化地基上浅基础建筑物沉降图表对试验中的堤坝沉降进行了推算,发现实测沉降与推算沉降比较接近。
A full sandy foundation is prone to be liquefied under an earthquake,explosion or other vibration loadings.As a result,the upper structures such as embankments on the foundation will be damaged.Aiming at the deformation problems of an embankment in a liquefied foundation,the field tests on explosion-induced liquefaction are conducted considering the effects of the embankment materials and reinforcement measures of the embankment foundation on its deformation and cracks.The results show that the subsidence of the embankment mainly occurs within 1 ~ 2 hours after the explosions,which accounts for 84 % ~ 87 % of the total subsidence accumulated in 7 days.The settlement of the embankment with fine aggregate becomes stable after 7 days.The subsidence of the embankment with fine aggregate is 24 % more than that without fine aggregate.The settlement of the foundation reinforced by geogrid and geotextile can be effectively reduced by 10% of the dam settlement in the liquefied ground.The cracks on the embankment body mainly appear in the section with fine aggregate and the interface between two different materials,and they extend along the dam body.The domestic and international specifications for the settlement of structures on a liquefied foundation are summarized.The settlement figure of buildings with shallow footings is adopted as the prediction method for the embankment settlement in this test.The results indicate that the predicted values are close to the measured data.
A full sandy foundation is prone to be liquefied under an earthquake,explosion or other vibration loadings.As a result,the upper structures such as embankments on the foundation will be damaged.Aiming at the deformation problems of an embankment in a liquefied foundation,the field tests on explosion-induced liquefaction are conducted considering the effects of the embankment materials and reinforcement measures of the embankment foundation on its deformation and cracks.The results show that the subsidence of the embankment mainly occurs within 1 ~ 2 hours after the explosions,which accounts for 84 % ~ 87 % of the total subsidence accumulated in 7 days.The settlement of the embankment with fine aggregate becomes stable after 7 days.The subsidence of the embankment with fine aggregate is 24 % more than that without fine aggregate.The settlement of the foundation reinforced by geogrid and geotextile can be effectively reduced by 10% of the dam settlement in the liquefied ground.The cracks on the embankment body mainly appear in the section with fine aggregate and the interface between two different materials,and they extend along the dam body.The domestic and international specifications for the settlement of structures on a liquefied foundation are summarized.The settlement figure of buildings with shallow footings is adopted as the prediction method for the embankment settlement in this test.The results indicate that the predicted values are close to the measured data.
引文
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[10]吴俊贤,倪至宽,高汉棪.土石坝的动态反应:离心机模型试验与数值模拟[J].岩石力学与工程学报,2007,26(1):1–14.(WU Jun-xian,NI Zhi-kuan,GAO Han-yan.Seismic reaction of earth and rockfill dam:centrifuge modeling test and numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(1):1–14.(in Chinese))
[11]孟上九,刘汉龙,袁晓铭,等.可液化地基上建筑物不均匀震陷机制的振动台试验研究[J].岩石力学与工程学报,2005,24(11):1978–1985.(MENG Shang-jiu,LIU Han-long,YUAN Xiao-ming,et al.Experimental study on mechanism of earthquake-induced differential settlement of building on liquescent subsoil by shaking table[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(11):1978–1985.(in Chinese))
[12]袁晓铭,孟凡超,孟上九,等.液化土层上建筑物倾斜计算要点初步分析[J].岩土力学,2007,28(增刊):687–692.(YUAN Xiao-ming,MENG Fan-chao,MENG Shang-jiu,et al.Key points for calculating inclination of buildings on liquefiable soil layers[J].Rock and Soil Mechanics,2007,28(S0):687–692.(in Chinese))
[13]WANG L,HE K,SHI Y,et al.tudy on liquefaction of saturated loess by in-situ explosion test[J].Earthquake Engineering and Engineering Vibration,2002(1):50–56.
[14]ASHFORD S A,ROLLINS K M.The Treasure Island liquefaction test[R].California:University of California,2001.
[15]ROLLINS K M.Liquefaction mitigation using vertical composite drains:full scale testing[R].Wastionton:Trunsportation Research Board,2004.
[16]刘汉龙,王维国,刘军,等.饱和砂土场地大型爆炸液化现场试验研究[J].岩土工程学报,2016.(LIU Han-long,WANG Wei-guo,LIU Jun,et al.Large-scale field tests of blast-induced liquefaction in saturated sand[J].Chinese Journal of Geotechnical Engineering,2016.(in Chinese))
[17]张意江,陈育民,王维国,等.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[J].岩土力学,2016,37(12):3506–3512.(ZHANG Yi-jiang,CHEN Yu-min,WANG Wei-guo,et al.Experimental investigation on dynamic response of shallow-buried reinforced concrete structure in blast-induced liquefied sandy foundation[J].Rock and Soil Mechanics,2016,37(12):3506–3512.(in Chinese))
[18]王维国.砂土场地爆炸效应及液化特性研究[D].南京:河海大学,2015.(WANG Wei-guo.Study on explosion effects and blast-induced liquefaction chracteristics in sand medium[D].Nanjing:Hohai University,2015.(in Chinese))
[19]DL 5073—2000水工建筑物抗震设计规范[S].2000.(DL5073—2000 Specifications for seismic design of hydaulic structures[S].2000.(in Chinese))
[20]GB 50011—2010建筑抗震设计规范[S].2010.(GB 50011—2010 Code for seismic design of buildings[S].2010.(in Chinese))
[21]International Standard Organization.ISO23469 Bases for design of structures-seismic actions for designing geotechnical works[S].2005.
[22]YOSHIMI Y,TOKIMATSU K.Settlement of buildings on saturated sand during earthquakes[J].Soils and Foundations,1997,17(1):23–38.
[2]CASTRO G,POULOS S J,LEATHERS F D.Re-examination of slide of lower San Fernando dam[J].Journal of Geotechnical Engineering,1985,111(9):1093–1107.
[3]ELKATEB T,CHALATURNYK R,ROBERTSON P K.Simplified geostatistical analysis of earthquake-induced ground response at the Wildlife Site,California,USA[J].Canadian Geotechnical Journal,2003,40(1):16–35.
[4]凌贤长,王丽霞,周宏.地震触发砂土液化总应力判别法——以北京密云水库白河主坝震害为例[J].地震工程与工程振动,2001,21(1):99–104.(LING Xian-chang,WANG Li-xia,ZHOU Hong.Ascertainment of sand liquefaction arising from earthquake by the method of comprehensive stress:taking seismic damage to Baihe principle dam of Miyun reservoir in Beijing,China,as an example[J].Earthquake Engineering and Engineering Vibration,2001,21(1):99–104.(in Chinese))
[5]赵剑明,温彦锋,刘小生,等.深厚覆盖层上高土石坝极限抗震能力分析[J].岩土力学,2010,31(增刊1):41–47.(ZHAO Jian-ming,WEN Yan-feng,LIU Xiao-sheng,et al.Study of maximum aseismic capability of high earth-rock dam on deep riverbed alluviums[J].Rock and Soil Mechanics,2010,31(S1):41–47.(in Chinese))
[6]Research Committee on Earthquake Engineering,Japanese Society of Civil Engineering.Subcommittee activity on behavior of earth structures undergoing strong earthquake motion[R].Tokyo:Japanese Society of Civil Engineering,2000.
[7]TOWHATA I.Geotechnical earthquake engineering[M].Berlin:Springer,2008.
[8]汪明武,IAI S,TOBITA T.液化场地堤坝地震响应动态土工离心试验及模拟[J].水利学报,2008,39(12):1346–1352.(WANG Ming-wu,IAI S,TOBITA T.Centrifuge test and numerical analysis of seismic responses of dyke on liquefiable soils foundation[J].Journal of Hydraulic Engineering,2008,39(12):1346–1352.(in Chinese))
[9]MAHARJAN M,TAKAHASHI A.Liquefaction-induced deformation of earthen embankments on non-homogeneous soil deposits under sequential ground motions[J].Soil Dynamics and Earthquake Engineering,Elsevier,2014,66:113–124.
[10]吴俊贤,倪至宽,高汉棪.土石坝的动态反应:离心机模型试验与数值模拟[J].岩石力学与工程学报,2007,26(1):1–14.(WU Jun-xian,NI Zhi-kuan,GAO Han-yan.Seismic reaction of earth and rockfill dam:centrifuge modeling test and numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(1):1–14.(in Chinese))
[11]孟上九,刘汉龙,袁晓铭,等.可液化地基上建筑物不均匀震陷机制的振动台试验研究[J].岩石力学与工程学报,2005,24(11):1978–1985.(MENG Shang-jiu,LIU Han-long,YUAN Xiao-ming,et al.Experimental study on mechanism of earthquake-induced differential settlement of building on liquescent subsoil by shaking table[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(11):1978–1985.(in Chinese))
[12]袁晓铭,孟凡超,孟上九,等.液化土层上建筑物倾斜计算要点初步分析[J].岩土力学,2007,28(增刊):687–692.(YUAN Xiao-ming,MENG Fan-chao,MENG Shang-jiu,et al.Key points for calculating inclination of buildings on liquefiable soil layers[J].Rock and Soil Mechanics,2007,28(S0):687–692.(in Chinese))
[13]WANG L,HE K,SHI Y,et al.tudy on liquefaction of saturated loess by in-situ explosion test[J].Earthquake Engineering and Engineering Vibration,2002(1):50–56.
[14]ASHFORD S A,ROLLINS K M.The Treasure Island liquefaction test[R].California:University of California,2001.
[15]ROLLINS K M.Liquefaction mitigation using vertical composite drains:full scale testing[R].Wastionton:Trunsportation Research Board,2004.
[16]刘汉龙,王维国,刘军,等.饱和砂土场地大型爆炸液化现场试验研究[J].岩土工程学报,2016.(LIU Han-long,WANG Wei-guo,LIU Jun,et al.Large-scale field tests of blast-induced liquefaction in saturated sand[J].Chinese Journal of Geotechnical Engineering,2016.(in Chinese))
[17]张意江,陈育民,王维国,等.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[J].岩土力学,2016,37(12):3506–3512.(ZHANG Yi-jiang,CHEN Yu-min,WANG Wei-guo,et al.Experimental investigation on dynamic response of shallow-buried reinforced concrete structure in blast-induced liquefied sandy foundation[J].Rock and Soil Mechanics,2016,37(12):3506–3512.(in Chinese))
[18]王维国.砂土场地爆炸效应及液化特性研究[D].南京:河海大学,2015.(WANG Wei-guo.Study on explosion effects and blast-induced liquefaction chracteristics in sand medium[D].Nanjing:Hohai University,2015.(in Chinese))
[19]DL 5073—2000水工建筑物抗震设计规范[S].2000.(DL5073—2000 Specifications for seismic design of hydaulic structures[S].2000.(in Chinese))
[20]GB 50011—2010建筑抗震设计规范[S].2010.(GB 50011—2010 Code for seismic design of buildings[S].2010.(in Chinese))
[21]International Standard Organization.ISO23469 Bases for design of structures-seismic actions for designing geotechnical works[S].2005.
[22]YOSHIMI Y,TOKIMATSU K.Settlement of buildings on saturated sand during earthquakes[J].Soils and Foundations,1997,17(1):23–38.