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在我国西部山区,大部分公路采用了路堑路堤的形式。针对坡度分别为1∶1.5和1∶1.75的半挖半填路堤,该文借助于大型通用有限元数值分析软件ABAQUS对其分别为进行了分析。本文选取“5.12”汶川地震加速度时程作为荷载输入,通过分析计算得路堤边坡在地震作用下产生的竖向位移以及峰值地面加速度PGA沿坡体高程的放大规律等结果,并将有限元分析结果与Newmark法计算结果进行比较发现,当采用原波进行Newmark法分析出的位移结果是偏小的,这主要没有考虑路堤在沿高度变化PGA有放大的作用。通过对PGA分别放大1.1、1.15、1.2、1.25倍后分析对比发现,对于坡度为1∶1.5和1∶1.75的路堤,有限元数值分析计算出的结果与PGA放大系数为1.25倍的计算结果比较吻合,PGA放大系数取1.25倍时有更高的可靠度。
In the western mountainous areas of our country, most of the roads adopt the form of cutting embankments. For the half-dug half-filled embankment with slope of 1: 1.5 and 1: 1.75 respectively, this paper analyzes them by means of the large-scale general finite element numerical analysis software ABAQUS. In this paper, the acceleration time history of “5.12 ” Wenchuan earthquake was selected as load input. Through the analysis and calculation, the vertical displacements of embankment slope under earthquake and the amplification law of PGA along the slope elevation were obtained. Compared with the result of Newmark method, the result of element analysis shows that when the original wave is applied to the Newmark method, the displacement result is small, which mainly does not consider the enlargement of the embankment along the height variation PGA. By comparing the PGA magnification of 1.1,1.15,1.2 and 1.25 times respectively, it is found that for the embankment with slope of 1: 1.5 and 1: 1.75, the calculated results by finite element numerical analysis are compared with those of PGA magnification of 1.25 times Anastomosis, PGA amplification factor to take 1.25 times higher reliability.