微型桩地震动力特性数值模拟研究

Research on Seismic Dynamic Numerical Simulation of Micropiles

微型桩是一种新型边坡支挡结构,地震中耗散能量较多,在边坡工程抗震抢险中被优先使用。目前微型桩的研究主要为静力特性的研究,对其动力特性的研究较少。运用数值软件FLAC3d对平行布置微型桩和"人"字形布置微型桩的动力学特性进行分析研究。研究表明:两类微型桩在地震作用下弯矩呈现"S"形分布特点,剪力呈现"〉"形的分布特点;当地震波峰值加速度<0.4g时,地震作用对两类微型桩的弯矩和剪力影响较小,当地震波峰值加速度≥0.4g时,地震作用对两类微型桩的弯矩和剪力影响较大;"人"字形微型桩同平行微型桩相比桩身弯矩较大、剪力较小,"人"字形微型桩的抗震承载能力更强,抗震效果更佳。

Micropile is a new retaining structure of side slope. As relatively much energy is dissipated when earthquake takes place,micropile is thus prioritized for earthquake emergence rescue in slope engineering. At present,the research on micropile is focused on static characteristics and less is on the dynamic characteristics of micropiles. In this paper,the dynamic characteristics of herringbone micropiles and parallel micropiles are analyzed and studied with the aid of the numerical software of FLAC3 d. The results show that the distributive characteristics of ＂S＂shape are demonstrated by the bending moment of two types of micropiles under earthquake action,and the shearing force is distributed in the shape of＂〉＂; when the seismic peak acceleration remains less than 0. 4 g,small impact is generated on the bending moment and the shearing force of different types of micropiles due to earthquake action; when the seismic peak acceleration becomes more than or equal to 0. 4 g,greater impact is caused; in comparison with the parallel micropiles,herringbone micropiles have large bending moment and small shearing force,and thus is found with strong seismic bearing capability and better anti-seismic efficiency.