Piled embankments have many advantages that have been applied in high-speed railway construction engineering.However,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still...Piled embankments have many advantages that have been applied in high-speed railway construction engineering.However,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still unclear,especially under dynamic loads.To investigate the soil arching and tension membrane under dynamic train loads on high-speed railways,a large-scale piled embankment model test with X-shaped piles as vertical reinforcement was performed,in which twenty-eight earth pressure cells were installed in the piled embankment and an M-shaped wave was adopted to simulate the high-speed railway train load.The results show that dynamic soil arching only occurs when two bogies of a carriage pass by and disappears at other times.The dynamic soil arching and membrane effect are the most significant under the concrete base.The arching height,stress concentration ratio and pile-soil load sharing ratio have a minimal value at 25 Hz.The dynamic soil arching degrades severely at 25 Hz,whose height at 25 Hz is only 0.35 times that at 5 Hz.The arching height fluctuates over a narrow range with increasing loading amplitude.The stress concentration ratio and the pile-soil load sharing ratio increase monotonically as the loading amplitude increases.展开更多
研究目的：为治理我国地铁环境振动问题,可采用多种减振轨道结构型式。浮轨式扣件作为新型减振扣件在国内应用较少,实际减振效果尚不明确,需结合实际工程开展现场试验,为地铁减振轨道设计提供参考。研究结论：在成都地铁2号线某区间,现...研究目的：为治理我国地铁环境振动问题,可采用多种减振轨道结构型式。浮轨式扣件作为新型减振扣件在国内应用较少,实际减振效果尚不明确,需结合实际工程开展现场试验,为地铁减振轨道设计提供参考。研究结论：在成都地铁2号线某区间,现场实测了浮轨式扣件替换DZⅢ型扣件前后的地面竖向振动加速度,通过时域与频域实测结果的对比分析得出：（1）浮轨式扣件使地面竖向振动加速度时程曲线从若干集中的振动簇变为分散均匀的振动模式,而且地面竖向振动加速度最大峰值不足DZⅢ型扣件的50%;（2）浮轨式扣件在1/3倍频程中心频率50～160 Hz的减振效果最为显著,VLzmax振级最高降幅可达21 d B;（3）在1/3倍频程中心频率1～160 Hz范围内,浮轨式扣件工况下所有测点的VLz综合振级为57.3～68.3 d B,其中绝大部分测点的VLz综合振级低于我国《城市区域环境振动标准》中特殊住宅区的标准值65 d B;（4）该研究成果可应用于地铁减振降噪工程领域。展开更多
基金Natural Science Research Project of Anhui Educational Committee under Grant No.2022AH050844Anhui Provincial Natural Science Foundation of China under Grant No.2008085ME143+1 种基金the Doctoral Foundation of Anhui University of Science and Technology under Grant No.13190018Innovation and Entrepreneurship Training Program for College Students under Grant No.S202110361059。
文摘Piled embankments have many advantages that have been applied in high-speed railway construction engineering.However,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still unclear,especially under dynamic loads.To investigate the soil arching and tension membrane under dynamic train loads on high-speed railways,a large-scale piled embankment model test with X-shaped piles as vertical reinforcement was performed,in which twenty-eight earth pressure cells were installed in the piled embankment and an M-shaped wave was adopted to simulate the high-speed railway train load.The results show that dynamic soil arching only occurs when two bogies of a carriage pass by and disappears at other times.The dynamic soil arching and membrane effect are the most significant under the concrete base.The arching height,stress concentration ratio and pile-soil load sharing ratio have a minimal value at 25 Hz.The dynamic soil arching degrades severely at 25 Hz,whose height at 25 Hz is only 0.35 times that at 5 Hz.The arching height fluctuates over a narrow range with increasing loading amplitude.The stress concentration ratio and the pile-soil load sharing ratio increase monotonically as the loading amplitude increases.
文摘研究目的：为治理我国地铁环境振动问题,可采用多种减振轨道结构型式。浮轨式扣件作为新型减振扣件在国内应用较少,实际减振效果尚不明确,需结合实际工程开展现场试验,为地铁减振轨道设计提供参考。研究结论：在成都地铁2号线某区间,现场实测了浮轨式扣件替换DZⅢ型扣件前后的地面竖向振动加速度,通过时域与频域实测结果的对比分析得出：（1）浮轨式扣件使地面竖向振动加速度时程曲线从若干集中的振动簇变为分散均匀的振动模式,而且地面竖向振动加速度最大峰值不足DZⅢ型扣件的50%;（2）浮轨式扣件在1/3倍频程中心频率50～160 Hz的减振效果最为显著,VLzmax振级最高降幅可达21 d B;（3）在1/3倍频程中心频率1～160 Hz范围内,浮轨式扣件工况下所有测点的VLz综合振级为57.3～68.3 d B,其中绝大部分测点的VLz综合振级低于我国《城市区域环境振动标准》中特殊住宅区的标准值65 d B;（4）该研究成果可应用于地铁减振降噪工程领域。
