【摘要】 调查、搜集和研究了汶川地震中被评定为高危以上险情的147座小型水库土坝的地震破坏情况,给出了高危以上险情土坝的地震破坏程度划分为中等破坏、严重破坏和极严重破坏三个等级的原则和标准,以及土坝的地震破坏程度与地震烈度、土坝的宽高比、上游坡比、坝高的经验关系表,可发现:土坝的几何形状对其破坏程度起着重要的作用;对于6～8度地震烈度区,土坝的宽高比越小,或上游坡比越小,或坝体越高,则土坝的破坏程度越严重;对于9度以上地震烈度区,土坝通常发生极严重破坏。依据高危以上险情土坝的地震反应分析结果,给出了土坝地震破坏程度与土坝宽高比、坝高、土坝上游坡比及坝顶加速度放大系数、坝体最大动剪应力的经验关系曲线,发现在相同的地震烈度水平下,土坝的宽高比越小,或上游坡比越小,或坝高越大,且坝顶加速度放大系数越大或坝体最大动剪应力越大,则其地震破坏程度越严重;坝体最大动剪应力超过30kPa的土坝,通常发生严重或极严重破坏,坝体最大动剪应力大于100kPa的土坝,通常发生极严重破坏;土坝离发震断层越远,则其坝顶加速度放大系数越大。本文给出的高危以上险情土坝的地震破坏程度与坝体几何形状的经验关系,可为今后土坝抗震设计提供参考依据。更多还原

【Abstract】 Based on the investigation and analysis of 147 high-risk earth dams in Wenchuan earthquake,the earthquake damage extent was divided into three levels: medium damage,serious damage and very serious damage.The empirical relationship among earthquake damage extent,earthquake intensity,aspect ratio,upstream slope ratio and height of earth dam was obtained.It was found that the geometry of the dam has an important effect on earthquake damage extent.For earthquake intensity 6~8,the smaller aspect ratio or the smaller upstream slope ratio or the greater height the earth dams had,the more serious the earthquake damage would be;for earthquake intensity above 9,the earth dams were generally damaged very seriously.Based on the seismic response analysis of the earth dams,the empirical relationship among earthquake damage extent,aspect ratio,upstream slope ratio,height of earth dams and acceleration amplification factor on dam crest,and the maximum dynamic shear stress in dam body were given.It could be seen that at the same earthquake intensity level,the smaller the aspect ratio or the smaller the upstream slope ratio or the higher the earth dams,and the greater the acceleration amplification factor on dam crest or the higher the dynamic shear stress in dam body,the more serious the earthquake damage.When the maximum dynamic shear stress in dam body is higher than 30 kPa,the dam was damaged seriously or very seriously.When the maximum dynamic shear stress in dam body is higher than 100 kPa,the dam was damaged very seriously.The farther the dam was located from the causative fault,the greater the acceleration amplification factor on dam crest was.In this paper,the empirical relationships between the damage extent and the geometry of the high-risk earth dams were established,which could give references for the seismic design of dams in the future.更多还原