Analysis Of Vibration Under Impact Load On Free Site

In the paper, we mainly researched on the propagation and attenuation law of wave in the soil, and introduced the harm and control countermeasure of environ--mental vibration. This paper chiefly based on tests and finite element simulation. On the base of former research achievements, research on the propagation law of vibration wave in the soil.For the test, this experiment was done on the ground of the history museum of Ch--engDu which was going to be built, and the test was a part of feasibility study of the m-useum. We gained the wave velocity in the soil was 120m/s, and the elastic modulus was 7.8e+107Pa, by analyzing the experimental data in the time domain. And the vibration acceleration gradually damped under far from the vibration source, and the acceleration damped in vertical direcion higher than horizontal direction. In the freqrency domain, we used three different material hammers as the vibration sources knocked on the ground, and our experiment found that the dominant frequencies were highly similar when the three different hammers knocked, and the dominnant frequency in horizontal direction ranged from 50Hz to 70Hz. And the vibration that generated by the rubber hammer was the most feeble. In order to verify the isolation effect of isolation trench, we respectively analyzed the vibration acceleration in transient and steady, and we found that the isolation effect of isolation trench was effecttive in a certain distance, and the isolation effect in transient was better than steady. When the distance between the vibration source and the isolation trench was fixed, the measuring point which nearby the isolation trench, its isolation effect was better than the point which was in distant. Also we simulated the impact load knocking on free site, through analyzing, we found that the maximum vibration acceleration gradually damped under far from the vibration source, and the vibration in vertical direction was stronger than it in horizontal direction. When the isolation trench nearby the vibration source, the isolation effect of the isolation trench was perfect, conversely, its isolation effect was poor.