地裂缝场地加速度响应振动台试验研究

地裂缝对工程结构的安全性影响巨大。在高烈度地区,若仍采用空间避让原则,势必浪费有限的土地资源,制约城市建设与经济发展。为了研究地裂缝场地的动力响应,使其得到更好的应用,以西安f4地裂缝为例,进行地裂缝场地地震动力响应振动台试验研究。试验结果分析表明:加速度放大系数与输入地震波类型和强度、土层性质和厚度及测点位置等因素有关;地裂缝场地加速度响应存在上、下盘效应,地表峰值加速度在裂缝处达到最大,并向两侧递减,下盘峰值加速度衰减速率比上盘快;裂缝两侧测点的加速度峰值存在时间差,上盘加速度变化频率较快。其研究成果将为地裂缝场地的工程应用提供参考。

Shaking table tests on acceleration response of ground fissure site

The ground fissure has brought severe damages to the engineering structures. In the area of high seismic intensity, if the spatial avoidance principle is still adopted, it will be bound to waste the land resources and restrict the urban construction. In order to study the dynamic response of ground fissure sites, taking the ground fissure of f₄ in Xi'an city as an example, the model test for the ground fissure site is carried out by means of the shaking table based on the laminar shear box. The test results show that the acceleration amplification factor is related to the type and intensity of input seismic waves, the properties and thickness of soil layers and the location of measuring points. Furthermore, the ground fissure site has hanging-wall/footwall effect. All the peak ground accelerations of the hanging-wall and footwall reach the maximum at the site of the fissure, they decrease from the fissure to the sides, and the rate of the hanging-wall peak acceleration attenuation is slower than that of the footwall. At the same time, the peak ground acceleration of the fissure at both sides has the time difference, and the acceleration change frequency of hanging-wall is faster than that of the footwall. The results may provide references for the engineering application of ground fissure sites.