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根据“5·12”汶川地震峰值加速度衰减关系,推求坝址基岩EW、NS、UD方向峰值加速度分别为0.52g、0.46g、0.43g,然后采用比例法将实测加速度记录(051MXT)换算得到紫坪铺大坝动力计算的输入加速度时程;在利用建设阶段变形监测资料反演堆石体静力模型参数得到大坝静应力的基础上,结合吉林台、猴子岩等工程室内试验资料类比得到了堆石体反映振动硬化特性动力模型的初步参数,并结合关门山、察汗乌苏等工程的现场原位试验资料和大坝实测地震加速度的频谱特性进行了调整复核;通过计算输入地震加速度的等效振动周数,利用实测资料对大坝堆石体的永久变形参数进行了反演分析。结论认为:振动硬化动力模型反映了大坝堆石体地震过程中的“震缩”现象,“5·12”汶川地震主震时间较长和坝址近震的铅直向加速度较大,是紫坪铺大坝震后永久变形较大的主要原因,Ⅱ、Ⅲ期混凝土面板的错台由于堆石体永久变形引起的次生破坏。现有土石坝动力分析理论和方法基本可以反映土石坝的抗震性能。
According to the attenuation relationship of the peak acceleration of Wenchuan earthquake, the peak accelerations of EW, NS and UD at the dam site are estimated to be 0.52g, 0.46g and 0.43g, respectively. Then, the measured acceleration (051MXT) The input acceleration time history of Zipingpu dam’s dynamic calculation is converted to obtain the static stress of the dam by using the deformation monitoring data during the construction phase to obtain the dam static stress. Based on the indoor test of Jilinlin and Monkey Rock The initial parameters of the dynamic model of rockfill body reflecting the characteristics of vibration and hardening were obtained by data analogy. The in situ test data of Guanmen Mountain and Chahanwusu and the spectrum characteristics of dam acceleration measured by the dam were adjusted and verified. The equivalent vibration weeks of earthquake acceleration are input, and the permanent deformation parameters of the dam rockfill body are analyzed by using the measured data. The conclusion is that the dynamic model of vibration hardening reflects the phenomenon of “Shrinking” during the seismic process of the dam rockfill body, the longer the main shock of the “5.12” Wenchuan earthquake and the vertical acceleration of dam near earthquakes It is the main reason that the permanent deformation of Zipingpu Dam is large after the earthquake. The dislocation of the stage II and III concrete slabs due to the permanent deformation of the rockfill body is caused by secondary damage. The existing earth-rock dam dynamic analysis theory and method can basically reflect the seismic performance of earth-rock dam.