汽车荷载作用下地下结构的现场振动试验研究

为了研究汽车荷载引起地下空间结构的低频振动和噪声问题，开展了地下结构现场振动试验。在结构顶板上下表面和地下一层布设测点，从时域及频域方面研究车辆振动下地下结构的振动响应，同时结合振级和噪声标准进行环境评价。结果表明：汽车荷载作用下地下结构以竖向振动为主，顶板竖向基频约为17.0Hz，振动能量主要集中于15.0~30.0Hz； 振动响应从顶板传递至地下一层时大幅衰减，顶板与地下一层的竖向振动沿水平方向传递不明显；顶板横向振动传递时衰减较慢； 测试荷载工况下，结构顶板竖向峰值加速度为274.38mm/s2、地下一层楼面Z振级最大81.02dB，噪声最大56.66dB，超过楼盖峰值加速度、振级与声环境质量限值，需采取减振降噪措施。

Field vibration test and analysis of underground structure under vehicle loads

In order to study the low frequency vibration and noise of underground space structures caused by vehicle loads, field vibration tests of an underground structure were carried out. The vibration responses of the underground structure were studied through time domain and frequency domain by setting measuring points on the upper and lower surface of the roof and the negative layer of the underground structure. The environmental evaluation based on vibration levels and noise standard was also carried out. The test results show that the vertical vibration of underground structure is dominant under the action of vehicle loads, the vertical fundamental frequency of roof is about 17.0 Hz, and the vibration energy is mainly concentrated in 15.0-30.0Hz. The vertical vibration responses attenuates greatly when transferred from the roof to the negative floor, and the law is not obvious when the vertical vibration is transferred along the horizontal direction between the roof and the negative floor. The transverse vibration transfer attenuation of the roof is slow. Under the test load conditions, the vertical peak acceleration of the roof is 274.38mm/s2, the maximum Z vibration level of negative floor is 81.02dB, and the maximum noise is 56.66dB, exceeding the limit values of floor vibration peak acceleration, vibration level and acoustic environment quality. The vibration and noise reduction measures should be taken.