Date Published: March 12, 2019
Publisher: Public Library of Science
Author(s): Gang Fan, Jianjing Zhang, Jinbiao Wu, Kongming Yan, Hao Sun.
The dynamic response analysis of horizontal and inclined layered sites using large-scale shaking table tests in various directions, including the dip direction, strike, vertical direction, slope direction and direction perpendicular to the interface of layered sites is conducted in this study. The Fourier spectrum and response spectrum characteristics in the horizontal site are first investigated in this study, and the dynamic responses of the inclined layered sites are then studied and compared to the corresponding responses of the horizontal layered site. The influence of dip angle on the response spectrum is also studied.
Construction is usually built on layered sites, including horizontal layered sites and inclined layered sites. A remarkable amount of researches regarding the dynamic response of horizontal layered sites have been carried out, and the results have been widely accepted . Nevertheless, there is little relevant literature on the dynamic responses of inclined layered sites with a small dip angle. Furthermore, inclined layered sites are more common than horizontal layered sites. In recent years, layered slopes and landslides have been widely studied by different researchers , however, the geologic structure of layered slopes and landslides differs significantly from that of inclined layered sites, which will lead to great differences in dynamic response characteristics. Consequently, the research results on layered slopes and landslides cannot be directly used to analyse the dynamic responses of layered sites. Because the relevant research concentrating on the seismic characteristic differences between horizontal and small dip angle inclined layered sites is rare, it is difficult to estimate the dynamic response of small dip angle inclined layered sites using the relevant research results of horizontal layered sites. Thus, the study on the seismic characteristic differences between horizontal and small dip angle inclined layered sites is important.
The differences and similarities of spectral characteristics between inclined layered sites and horizontal layered sites were compared in this paper using large scale shaking table tests, and the corresponding results were quantitatively analysed. The largest dip angle of the inclined layered sites in this model test was just 12.5°, so the model site should be defined as a small dip angle inclined layered site. Because some obtained results in this paper cannot be explained according to the current state of knowledge, whether the test result is suitable for larger dip angle inclined layered sites (i.e., θ > 12.5°) requires further study, and the research results in this paper require further practical verification and complement.
According to the analyses of the test results, the following conclusions can be drawn.