基于原位试验地下高铁车致环境振动特性分析

Analysis on Ground Vibration Properties Induced by Underground High-speed Railway Based on In-situ Experiment

研究目的:高速铁路下穿综合交通枢纽的交通交叉形式日渐兴起,地下高铁引发的环境振动问题不容忽视。为探明地下高铁运行对地表环境振动影响规律,结合在建高铁下穿机场场地工程实例,设计高铁隧道内落轴试验得到周围土体环境振动特征,建立车-轨-隧-地层半解析计算模型得到列车荷载动力初始条件,预测分析地下高铁车致环境振动幅频特性及传播规律,研究不同行车条件、轨道参数和隧道埋深的影响特点。研究结论:(1)地表振动在离线路中心线10 m范围内大幅衰减,衰减率达70%,垂向振动幅值明显大于其他两个方向,地表横向振幅最小,振动衰减速度最慢;(2)在350 km/h高速列车通过条件下,80 m范围内地表垂向和横向振级分别为20~80dB、43~72dB,Z振级最大衰减系数达0.276dB/m;(3)列车速度每提升50 km/h,地表Z振级增加约2 dB;(4)在13~50 Hz内,扣件刚度越小地表振级越大,在79 Hz以上,地表振级与扣件刚度正相关;(5)隧道埋深大于14 m时,隧道埋深对地表Z振级变化影响较小,将高铁隧道埋深控制在合理范围内可减小地表振动;(6)本研究成果可为下穿高速铁路设计和研究提供参考和借鉴。

Research purposes:The transportation intersection form of railway under-passing transportation hub gradually becomes popular,the ground vibration due to the underground railway cannot be ignored.In order to determine the influence law of the operation of the underground high-speed railway on the ground vibration,according to engineering project of the high-speed railway underpassing the airport site under construction,the dropping-wheel test was conducted in the high-speed railway tunnel to obtain the vibration properties of the surrounding soils.And the semi-analytical calculation model of the vehicle-track-tunnel-ground layer was established to obtain the dynamic initial conditions of the vehicle loads.The amplitude-frequency characteristics and transmission law of the ground vibration induced by the underground high-speed railway were analyzed and the effects of the different vehicle speed,track parameters and tunnel burial depth were discussed.Research conclusions:(1)The ground vibration decays significantly within 10 m from the centerline of the railway line with the attenuation rate of 70%.The vertical vibration amplitude is significantly larger than that of the other two directions.The lateral amplitude is the smallest with the slowest decay rate.(2)Under the condition of 350 km/h for the high-speed railway,the vertical and lateral ground vibration within 80 m reaches 20~80 dB and 43~72 dB respectively.The maximum attenuation coefficient of Z-vibration level reaches 0.276 dB/m.(3)The Z-vibration level of the ground increases by about 2 dB with the vehicle speed increasing by 50 km/h.(4)The smaller fastener stiffness leads to the larger ground vibration within 13~50 Hz,while the ground vibration is positively correlated with the fastener stiffness above 79 Hz.(5)When the tunnel burial depth is larger than 14 m,the tunnel burial depth has little influence on the change of the Z-vibration level of the ground,so the ground vibration can be reduced by limiting the burial depth of the high-speed railway tunnel to a reasonable range.(6)The research achievements can provide a reference for the design and research of the under-passing high-speed railway.