基于复频散曲线特征的周期结构高铁路基减振研究

Vibration reduction of high-speed railway subgrade with periodic structures based on complex dispersion curves

目前对周期排桩衰减域的研究只停留在频散曲线分析阶段,只有少数学者利用二维复频散曲线来研究周期排桩衰减域,而频散曲线只能得到衰减域的范围,复频散曲线能得到振动波在衰减域内的衰减程度。利用COMSOL PDE模块求解三维模型的复频散曲线,通过对排桩排布形式和不同桩身材料的影响进行分析得到:三角形排布的排桩衰减域范围最广且减振效果最好;当桩身材料为混凝土或钢时,能产生高频衰减域,而使用两组元桩时可以产生低频衰减域,但两组元桩和混凝土桩的减振程度比钢桩小。最后,通过建立有限尺度的周期排桩频域响应模型验证了复频散曲线计算的正确性,同时对高铁荷载引起的地基振动特征频率0~50Hz,提出针对不同频率减振的4种类型桩和1种组合桩,结果说明组合桩能结合4种类型排桩产生衰减域频率分布的特点,且减振效果较好。

At present,the researches on the attenuation zone of periodic row piles only stay in the stage of dispersion curve analysis.Only a few scholars have studied complex dispersion curves of 2 D model.The dispersion curve can only obtain the range of the attenuation zone,while the complex dispersion curve can obtain its attenuation degree.In this study,the COMSOL PDE module is used to solve the complex dispersion curve of 3 D model.By analyzing the influence of arrangement forms and materials of piles,it is found that the piles in triangular arrangement have the widest attenuation zone and the best vibration reduction effect.When the material of piles is concrete or steel,the attenuation zone in high frequency can be obtained,and the attenuation zone in low frequency can be obtained when two-component piles are used.The vibration reduction degrees of the two-component piles and concrete piles are smaller than those of the steel piles.Finally,a finite-scale frequency domain response model for periodic row piles is established to verify the correctness of the complex dispersion curve.As the characteristic frequency of the foundation vibration caused by the high-speed railway is within 0~50 Hz,four types of piles with different attenuation zones and one kind of composite piles are put forward.The results show that the composite piles can combine the attenuation zones of four types of row piles,and the vibration reduction effect is good.