基于现场试验的高铁路基智能压实过程中振动波垂向传播机制

以京雄城际铁路固安车站的路基段作为试验场地,从时域、频域、时频域及能量4个方面,研究振动压实过程中不同深度填料的动力特性及振动波从振动轮至填料全过程的传播机制。结果表明:振动信号从振动轮至填料的传播过程中,振动加速度峰值近似呈双曲线分布,且与埋深呈反向关系,其传播的临界深度为1.0 m左右;振动信号传播至填料中,基波频率有所增大,基波与各次谐波的幅值则逐渐减小;在任意埋深处,振动信号的基波、1次、2次至5次谐波的幅值呈现指数递减,具有严格的指数函数相关性;Hilbert-Huang变换谱能够全面、系统地反映任意时刻振动信号的时域特征,振动压路机对于填料的有效碾压时间大致为2 s;振动能量主要集中在20~50 Hz频率内,与基波和1次谐波频率基本一致;随着埋深的增加,振动能量逐渐减小,特别是在振动波从振动轮传至填料表面时,振动能量的损耗最为严重。

Vertical Propagation Mechanism of Vibration Wave in Intelligent Compaction Process of High-Speed Railway Subgrade Based on Field Test

The subgrade section of Gu’an Station of Jingxiong intercity railway was selected as the test site.The dynamic characteristics of different depth fillers during vibration and compaction as well as the propagation mechanism of vibration wave in the whole process from the vibrating wheel to filler were studied from the time domain,frequency domain,time-frequency domain and energy domain.Results show that,in the process of vibration signal propagation from the vibrating wheel to the filler,the peak value of vibration acceleration is approximately hyperbolic,which is inversely related to the buried depth,and the critical depth of vibration signal propagation is about 1.0 m.When the vibration signal propagates to the filler,its fundamental frequency will increase,and the amplitude of its fundamental and harmonic waves will gradually decrease.In any buried depth,the amplitude of the fundamental,primary,secondary and fifth harmonic of vibration signal decreases exponentially,which has strict exponential function correlation.Hilbert Huang transform spectrum can comprehensively and systematically reflect the time-domain characteristics of vibration signals at any time,and the effective rolling time of vibratory roller for filler is about 2s.The vibration energy is mainly concentrated near the frequency of 20 Hz^50 Hz,which is basically consistent with the fundamental and first harmonic frequencies.With the increase of the buried depth,the vibration energy decreases gradually,especially when the vibration wave is transmitted from the vibrating wheel to the surface of the filler,the loss of the vibration energy is the most serious.