(1. Key Laboratory of Traffic Tunnel Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;2. China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,Hubei 430063,China;3. School of Civil and Architectural Engineering,Wuhan University,Wuhan,Hubei 430072,China;4. Guangdong Research Institute of Water Resources and Hydropower,Guangzhou,Guangdong 510610,China)
Abstract:Ground vibration induced by high-speed train in Shiziyang tunnel which lies in fine sand layer stratum is measured. At the speed of 310 km/h,the maximum acceleration on top of the tunnel is 10.78 cm/s2,while the maximum velocity is 0.034 cm/s;vibration energy is mainly concentrated within 60 Hz,main frequencies are in 30–40 Hz,and the predominant frequency decreases with distance. There is obvious amplification for acceleration in the range of 30–40 m. Analogy analysis shows that by using damping cushion in the track system the environmental vibration is small,and is in the same order of magnitude as low speed subway,lower than that of subway without dumping measures,while slightly higher than that of subway with steel spring floating slab track. In some points,the circumferential and radial vibrations are larger than the vertical vibration,so it is suggested that attention should also be paid to the influence of horizontal ground vibration on buildings beside that induced by vertical vibration. A data center of environmental response induced by underground highs-peed trains is formed,based on it prediction for ground vibration by multi-dimensional interpolation can be executed. A empirical formula of extreme value type is also put forward to describe the ground vibration distribution,by which more vibration evaluation can be accomplished conveniently.