京津城际铁路桥墩基础场地振动测试与分析

为确定京津城际铁路地震预警系统地震仪的触动阀值,在高速列车通过时,对京津城际铁路桥墩基础场地进行了振动测试,并采用最小二乘法及频谱分析获得了桥墩附近场地的振动加速度衰减规律及其频率特性。结果表明,振动加速度幅值在距离桥墩10 m范围内衰减很快,且垂直向衰减比水平向快,超过10 m范围后,衰减变缓,水平向与垂直向的振动幅值衰减接近;在桥墩附近,加速度水平向及垂直向主振频率分别为37 Hz和41 Hz,远高于理论预测值;距桥墩70 m处安置的地震仪不会被触发。

Testing and analysis of ground vibration induced by a high-speed train on Beijing-Tianjin railway

To confirm the triggered threshold value of a seismograph of the earthquake warning system of Beijing-Tianjin railway, the ground vibrations of pier foundations induced by a high-speed train were tested. The acceleration at-tenuation law and frequency characteristics were obtained by frequency spectrum analysis and the method of least squares.The results showed that amplitudes of acceleration rapidly decrease and the vertical one more rapidly decrease than the horizontal ones within 10 meters from a pier, but slowly decrease in the distance range of above 10 meters, and vertical and horizontal attenuation are similar; the main frequency in the horizontal direction is 37Hz, and the one in the vertical direction is 41Hz, much higher than the predictions by theory, and the seismograph can not be triggered at the distance of 70 meters from a pier.