摘要
地震的频发促使人们研究各种结构在地震作用下的响应。本文以重庆市某滨江路护岸工程的加筋土挡墙为例,利用三维快速拉格郎日法(简称FLAC3D)对不同地震荷载作用下的加筋土挡墙稳定和变形进行了数值模拟分析。并与其它相关研究结果进行了比较,获得的主要成果如下:
(1)在地震荷载作用下,加筋土挡墙墙面的横向位移比静力作用下增加较大,而且随地震设计烈度的增加位移呈较快增长,并随墙高度的增加而增加。
(2)对一般土质地基上的加筋土挡墙,在强震作用下(如地震设计烈度为8度时),由于加筋体填土在地震作用下逐渐振动密实,填土压缩变形,加筋填土与墙面板间出现差异沉降,筋带产生明显的拉伸变形,呈现上大下小的变化分布。
(3)在不同的地震荷载作用下,加筋挡墙的筋带拉力随墙高增加而减小,筋带拉力最大值仍出现在加筋体底层。各层筋带最大拉力值点离墙面距离随墙高度增加而缓缓增加。
(4)随地震设计烈度的增加,加筋体的屈服单元也逐渐增加,在设计烈度为8度时,地震时大部分单元都表现出屈服状态。且随设计烈度增加,加筋土挡墙的潜在破裂面向离墙面较远的区域扩展;地震烈度越高,加筋体发生破坏的范围越大。
Frequent earthquake urged people to study the response of various structures under earthquake. Using three-dimensional fast Lagrangian method (referred to as FLAC3D), it was carried out numerical simulation to stability and deformation of the reinforced retaining wall under different seismic intensity for the embankment of Binjiang Road in Chongqing. Compared with other related study results, the main results as follows:
(1) The wall’s lateral displacement of the reinforced retaining wall under earthquake was bigger than under static, and the bigger seismic intensity, the faster the displacement increasing. The deformation was bigger and bigger from the bed to top of the wall.
(2) For the reinforced retaining wall based on soil foundation, there was a differential settlement between filler and wall under strong earthquake( especially under 8 degree). The filler was vibrated and compacted, the bar appeared a distinct stretcher strain, it was presented big in top and small in bottom of wall.
(3) For different seismic intensity, the bar tension force in reinforced wall was still decreased with the height of wall and the maximum tension was appeared in the bottom layer. The spacing between the wall face and maximum tension point of various layer was increased stably from bottom layer to top layer.
(4) The yield unit in reinforced retaining wall was increased with the seismic intensity increasing, especially in the intensity of 8 degree, most of the units have been yield. And with the seismic intensity increased, the potential rupture surfaces of the reinforced wall was spread to the rear part of the wall body. The greater the seismic intensity, the greater scope of damage occupied in the reinforced wall.
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