黄土丘陵沟壑区挖填场地动力响应特征研究

Study on Characteristics of Dynamic Response at Digging-filling Sites in the Loess Hilly and Gully Region

以黄土丘陵沟壑地区大规模平山填沟造地工程为背景,结合相关工程实例,定量分析新型挖填场地在地震作用下场地动力响应特征及其关键影响因素。以场地地球物理勘测和压实黄土室内动三轴试验为基础,构建考虑场地横向不均匀性的场地地震反应分析模型,给出场地填方厚度、挖填交界面和土层参数对场地挖方区、填土区和界面区地震动特征参数的影响规律。研究发现:场地覆盖土层厚度在一定范围内对地震动峰值加速度影响明显,而大厚度覆盖层对地震波能量传递有抑制作用;填方土层压实参数影响填方区地震动放大范围;挖填界面的平均坡度和界面阻抗对平面内地震波场折射和反射影响较大。研究结果可为黄土地区大规模挖填场地地震稳定性分析提供参考依据。

Based on the large-scale reclamation project by digging hill and filling gully in the loess hilly and gully region,combined with relevant engineering examples,the dynamic response characteristics and key influencing factors of the new digging-filling sites under earthquake action are quantitatively analyzed.Considering site geophysical survey and dynamic triaxial tests of compacted loess,a site seismic response analysis model for lateral heterogeneity is constructed.The influence of site filling thickness,digging-filling interface and loess mechanical parameters on ground motion characteristic parameters in the digging,filling,and transition areas is given.It is found that:the overburden thickness of loess has a significant effect on the peak acceleration of ground motion in a certain range,while the overburden thickness beyond a given height has a restraint effect on seismic waves;the compaction parameters of the filling layer affect the range of ground motion amplification in the filling area;the average slope of the digging-filling interface and the interface impedance affect refraction and reflection of the seismic waves fields in plane.The research results can provide a reference for seismic stability analysis of large-scale digging-filling sites in the loess region and have certain practical significance.