地表刚性对地震液化作用的影响(英文)
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摘要
一种新的假说阐述了在大地震中饱和沙土的液化现象。这是建立在多反射理论和FEM动力反应计算的基础上的。计算中应用了在1994年三陆外海M7.5地震时对八户港土层的假设,其结果与观测到的地震现象十分符合。这种方法也被应用于其他曾经发生液化的地区并被证实是在液化机理可接受限度内。富井地震(1948年6月,M=7.1)发生在福井盆地中央,深度为15 km,引起了大范围的破坏,伤亡人数达到5 300人。这次地震在各处引起大面积的液化,导致大范围的稻田被砂石所覆盖。但是,尽管加速度很大,盆地的几部分没有被液化。应用这种假说,我们分析了在相同情况下地表层的差异。结果发现液化的产生取决于地表层刚性引起的应变大小,假设与实际情况一致。
A new hypothesis clarifies the phenomenon of liquefaction of saturated sandy soil during large earthquakes.It is based on the multi-reflection theory and dynamic response calculation using FEM.The results using the hypothesis applied to soil at Hachinohe Port during the 1994 Far-Off Sanriku Earthquake(M=7.5) in calculating,showed good correspondence with the observed phenomena associated with this earthquake.The method was applied to other areas that had liquefied in the past and confirmed within acceptable limits the mechanism of liquefaction.The Fukui Earthquake(June,1948,M=7.1) occurred at depth of 15 km at the center of the Fukui basin and caused widespread damage and 5 300 casualties.The earthquake induced large-scale liquefaction everywhere and covered rice field over a wide area with sand and gravel.However,regardless of very strong acceleration several parts of the basin did not liquefy.Using the hypothesis,we analyzed differences in surface layer under the same conditions.As a result,we found that the liquefaction depends on the size of strain caused by the rigidity of the surface layer and that the hypothesis accurately corresponds to what happens in practice.
A new hypothesis clarifies the phenomenon of liquefaction of saturated sandy soil during large earthquakes.It is based on the multi-reflection theory and dynamic response calculation using FEM.The results using the hypothesis applied to soil at Hachinohe Port during the 1994 Far-Off Sanriku Earthquake(M=7.5) in calculating,showed good correspondence with the observed phenomena associated with this earthquake.The method was applied to other areas that had liquefied in the past and confirmed within acceptable limits the mechanism of liquefaction.The Fukui Earthquake(June,1948,M=7.1) occurred at depth of 15 km at the center of the Fukui basin and caused widespread damage and 5 300 casualties.The earthquake induced large-scale liquefaction everywhere and covered rice field over a wide area with sand and gravel.However,regardless of very strong acceleration several parts of the basin did not liquefy.Using the hypothesis,we analyzed differences in surface layer under the same conditions.As a result,we found that the liquefaction depends on the size of strain caused by the rigidity of the surface layer and that the hypothesis accurately corresponds to what happens in practice.
引文
[1]Y Shioi.Experimental study on liquefaction of sandy soil[A].in:7thWorld Conference for Earthquake Engineering[C].Is-tanbul,1980.
[2]Y Hashizume,Y Shioi.Mechanism of liquefaction of sandyground during a great earthquake and countermeasures forhighway bridges[A].in:UJNR 16thUS-Japan bridge engi-neering workshop[C].Lake Tahoe,2000.35-48.
[3]Y Shioi,Y Hashizume.Mechanism Liquefaction of sandyground during large earthquake[A].in:10thSDEE 2001,Ex-tended abstract[C].Philadelphia,2001.189.
[4]Y Shioi,N Sakajiri.Seismic damage to civil engineering struc-tures by the 1994 Far-Off Sanriku Earthquake[A].in:11thWorld Conference for Earthquake Engineering[C].CD-ROM,Summary,1996.1257.
[2]Y Hashizume,Y Shioi.Mechanism of liquefaction of sandyground during a great earthquake and countermeasures forhighway bridges[A].in:UJNR 16thUS-Japan bridge engi-neering workshop[C].Lake Tahoe,2000.35-48.
[3]Y Shioi,Y Hashizume.Mechanism Liquefaction of sandyground during large earthquake[A].in:10thSDEE 2001,Ex-tended abstract[C].Philadelphia,2001.189.
[4]Y Shioi,N Sakajiri.Seismic damage to civil engineering struc-tures by the 1994 Far-Off Sanriku Earthquake[A].in:11thWorld Conference for Earthquake Engineering[C].CD-ROM,Summary,1996.1257.
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