土工格栅返包土工袋加筋土挡墙的地震响应分析及设计建议

发布时间：2018-11-24 08:35

【摘要】：为了研究土工袋加筋土挡墙在地震作用下的抗震性能,开展了大型的振动台模型试验。结果表明:随着加载的持续进行,挡墙模型的自振频率降低,阻尼比增加;PGA放大系数随输入地震动峰值加速度的增大而减小,墙高对PGA放大系数的影响反倒不大。土工袋加筋土挡墙的峰值动土压力呈现"中间小,两头大"的分布规律,且墙高越高,输入地震动峰值加速度越大,峰值动土压力越大,而不同地震波形的频谱差异对土压力量值和分布的影响较小。通过数值模拟研究了坡度对土工袋加筋土挡墙力学特性的影响,认为土工袋加筋土挡墙墙后侧向土压力和筋材的拉应力随着墙体坡度的增大而增大,当墙体坡度小于1∶0.75时,侧向土压力较小;当墙体坡度大于1∶0.75时,墙后土压力迅速增加,土压力的分布图式类似呈三角形分布。筋材的拉应力沿长度方向呈单峰型分布,各层筋材的拉应力随上覆填土厚度的增加而增大,但增加的幅度逐渐减小。另外,土工袋加筋土挡墙的剪应变增量、活动区范围以及位移均随墙体坡度的增大而增大。
[Abstract]:In order to study the seismic behavior of geotextile reinforced earth retaining wall under earthquake, a large scale shaking table model test was carried out. The results show that the natural frequency of the retaining wall model decreases and the damping ratio increases with the continuous loading, and the PGA magnification coefficient decreases with the increase of the peak acceleration of the input ground motion, while the influence of the wall height on the PGA magnification factor is not significant. The peak dynamic pressure of geotextile reinforced earth retaining wall is "small in the middle and large in both ends", and the higher the wall height, the greater the peak acceleration of input ground motion and the greater the peak dynamic pressure. The difference of frequency spectrum of different seismic waveforms has little effect on the magnitude and distribution of earth pressure. The influence of slope on the mechanical properties of reinforced earth retaining wall with geotextile is studied by numerical simulation. It is considered that the lateral earth pressure and tensile stress of reinforced earth retaining wall increase with the increase of slope of the wall. When the slope of the wall is less than 1: 0.75, the lateral earth pressure is lower. When the slope of the wall is greater than 1: 0.75, the earth pressure behind the wall increases rapidly, and the distribution of earth pressure is similar to that of triangular distribution. The tensile stress of the steel bar distributes as a single peak along the length direction, and the tensile stress of each layer increases with the increase of the overburden thickness, but the increasing amplitude decreases gradually. In addition, the increment of shear strain, the range of active zone and the displacement of the reinforced earth retaining wall increase with the increase of the slope of the wall.
【作者单位】：西南科技大学环境与资源学院;西南交通大学土木工程学院;四川省交通运输厅交通勘察设计研究院;四川建筑职业技术学院;
【基金】：国家自然科学基金项目(41172321) 中国铁路总公司科技研究开发计划课题(2014G004-A-6)
【分类号】：TU476.4

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