废弃钢渣回填土工格栅加筋挡土墙的抗震性能振动台试验

为了研究废弃钢渣回填土工格栅加筋挡土墙在地震作用下的抗震性能，根据量纲分析理论中的Froude常数与相似比原理设计了土工格栅加筋挡土墙振动台试验模型，利用汶川地震近场什邡波（SF）和远场松潘波（SP）作为主要加载波形，以废弃钢渣为回填料，开展了土工格栅加筋钢渣挡墙的振动台模型试验。考虑地震强度的影响研究加筋挡土墙在不同地震波、不同地震强度下的墙体位移、水平加速度、回填料加速度、回填料表面竖向沉降以及土工格栅动应变等反应规律。为了将钢渣回填土工格栅加筋挡土墙的反应特性与传统砂土回填加筋挡土墙的反应特性作比较，开展了传统砂土回填土工格栅层的挡土墙抗震性能研究。试验结果表明：在不同加载强度下，远场SP波加载时的墙体加速度放大系数均大于近场SF波加载时墙体的加速度放大系数，挡土墙在加载远场SP波时比加载近场SF波时的反应更为激烈；在相同的地震波、地震强度下，通过对比钢渣和砂作为填料时的墙体和回填料的加速度、墙体变形和回填料沉降反应特征，得出质重且级配良好的钢渣作为加筋挡土墙回填料时，加筋墙体具有良好的抗震作用。在地震作用下，土工格栅应变峰值随墙高的分布情况为"上下小，中间大"，与静态下格栅应变规律一致。研究结果表明废弃钢渣回填土工格栅加筋挡土墙可以应用到工程实践中。

Shaking Table Tests on Seismic Behavior of Geogrid-reinforced Retaining Wall with Waste Steel Slag Backfill

In this study,a shaking table test model of a geogrid-reinforced retaining wall was designed according to the Froude constant and similarity ratio principle in dimensional analysis theory to study the dynamic characteristics of geogrid-reinforced retaining walls with backfill during an earthquake. Shaking table model tests on the seismic performance of geogrid-reinforced retaining walls were conducted with the near-field Shifang( SF) wave and the far-field Songpan( SP) wave as main loading waveforms,and waste steel slag as backfill. The effects of seismic waves and seismic intensity at near and far sites were considered. Some response laws of the geogrid-reinforced retaining wall under different seismic waves and earthquake intensities were studied, such as wall displacement, horizontal acceleration, backfill acceleration,vertical settlement of the backfill surface,and dynamic strain of the geogrid. The seismic performance of the steel slag backfill geogrid-reinforced retaining wall was compared with that of a traditional sand backfill-reinforced retaining wall,and the seismic behavior of the retaining wall of the sand backfill geogrid layer was studied. The experimental results showed that the wall acceleration amplification factor under far-field SP wave loading was greater than that under near-field SF wave loading. The acceleration amplification factors of the retaining wall under far-field SP wave loading were greater than those under near-field SF wave loading. Under the same seismic waves and intensities,a comparison of the settlement and acceleration of steel slag with sand as backfill and the effect of backfill on wall deformation,showed that the steel slag with good weight and gradation had better seismic resistance than the sand backfill of the reinforced retaining wall. Under the action of an earthquake,the distribution of the peak strain value of the geogrid with the height of the wall was "small up and down,large in the middle,"which is consistent with the strain law of geogrids under static condition. These results demonstrate that geogrid-reinforced retaining walls with waste steel slag backfill have better seismic performance and can be applied in engineering practice.