变频规则波输入下直斜群桩动力响应对比试验研究

通过对2×2直斜群桩结构进行振动台模型相似比设计,围绕不同频率正弦波输入下的非液化砂土与饱和砂土中群桩-承台-上部结构体系开展横向动力响应特性试验研究。结果表明:①在输入相同频率正弦波情况下,无论是直桩群还是斜桩群,其位于饱和砂土中的动力响应放大倍数均大于相应非液化砂土工况下的放大系数,且直群桩的横向动力响应比斜群桩动力响应更显著;②随着输入波频率的增加,各试验工况的承台结构动力反应系数均有所增长,直桩群和斜桩群在饱和砂土工况中的加速度和位移的放大倍数增长较非液化砂土工况明显,直群桩比斜群桩增长显著。

Comparative Experimental Study on Dynamic Response of Straight Inclined Piles under Variable Frequency Regular Wave Input

Through the similarity ratio design of the shaking table model for 2×2 straight oblique group piles, the lateral dynamics of the group-piling-superstructure system in non-liquefied sand and saturated sand under excitation of sine waves with different frequencies are carried out. The experimental results show that: (1) In the case of the sine wave with the same frequency, the dynamic response magnification in the saturated sand is greater than that in the non-liquefied sand for both straight pile group and diagonal pile group. The lateral dynamic response of the straight group pile is more significant than that of the inclined pile group. (2) With the increase of the frequency of the input wave, the dynamic response coefficient of the bearing structure in each test condition increases, and the increments of the acceleration and the displacement of both straight pile group and inclined pile group in the saturated sand condition is more obvious than that in the non-liquefied sand condition. The dynamic response of the straight pile group is more significant than that of the inclined pile group. The research results of this paper provide a scientific reference for the seismic theory of pile foundation, and serve the design of related pile foundation engineering in the future.