基于振动台模型试验的二元结构边坡地震动力响应研究

发布时间：2018-06-01 20:16

本文选题：振动台模型试验 + 二元结构边坡　；参考：《工程地质学报》2017年01期

【摘要】：在强震区,地震诱发边坡失稳等地质灾害的安全隐患十分突出。同时,针对由上覆松散堆积物和下卧基岩构成的土岩二元结构边坡,其地震作用下动力响应的相关研究仍较为少见。因此本文以海西福永高速ZK132+300段典型土岩二元结构边坡为原型,设计制作了1/20缩尺模型边坡,在福建省土木工程灾害防治重点实验室的双向地震模拟振动台上,完成了20种工况的模拟地震动试验。重点关注坡体高程、地震动幅值、地震动频率特征对PGA放大系数的影响,得到以下结论。坡内和坡面各测点处PGA放大系数,均呈现出明显的高程效应和鞭梢效应;但锚框支护能有效抑制坡面的趋表效应。随着输入地震动幅值的增大,土体表现出明显的塑性特征,坡内和坡面各测点处PGA放大系数,按高程依次呈线性减小或指数型减小。在相同幅值、不同频率特征的地震波作用下,坡面各测点处PGA放大系数呈现出明显的差异性;但这种因地震波频谱特性不同而产生的差异,随着高程增加而逐渐减小,并在坡顶处趋向一致。同时通过对边坡表观破坏特征的描述,发现二元结构边坡的裂缝发展仅出现在上部土质坡体的坡顶和坡肩自由面附近,未出现贯通性裂缝和整体滑移失稳,认为锚框支护结构极大提高了上部土质边坡的抗震性能。
[Abstract]:In strong earthquake area, the safety hidden danger of slope instability caused by earthquake is very prominent. At the same time, the study on dynamic response of soil and rock bivariate slope composed of overlying loose deposits and underlying bedrock is still rare. Therefore, based on the typical soil-rock dual structure slope of ZK132 300 section of Haixi Fuyong High Speed, a 1 / 20 scale model slope is designed and manufactured, which is used on the bi-directional earthquake simulation shaking table of the key Laboratory of Civil Engineering disaster Prevention in Fujian Province. The simulated ground motion tests under 20 different operating conditions have been completed. The influence of slope height, amplitude of ground motion and frequency characteristics of ground motion on PGA magnification factor is emphasized, and the following conclusions are obtained. The PGA magnification factor in the slope and at each measuring point on the slope shows obvious elevation effect and whipping effect, but the anchor frame support can effectively restrain the topographic effect on the slope surface. With the increase of the amplitude of the input ground motion, the soil shows obvious plastic characteristics. The PGA magnification factor at the measured points in the slope and the slope surface decreases linearly or exponentially according to the elevation. Under the action of seismic waves with the same amplitude and different frequency characteristics, the PGA magnification coefficient at different measuring points on the slope surface shows obvious difference, but the difference caused by the different frequency spectrum characteristics of the seismic wave gradually decreases with the increase of height. And at the top of the slope tend to be consistent. At the same time, through the description of the apparent failure characteristics of the slope, it is found that the crack development of the dual structure slope only occurs near the top of the upper soil slope body and the free surface of the slope shoulder, and there is no penetrating crack and integral slip instability. It is considered that the Anchor-frame support structure greatly improves the seismic performance of the upper soil slope.
【作者单位】：福州大学土木工程学院;同济大学岩土及地下工程教育部重点实验室;
【基金】：同济大学岩土及地下工程教育部重点实验室开放基金(KLE-TJGE-B1404)资助
【分类号】：TU435

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