不同基础振动对地表动力响应影响的模型试验

Model testing for influence of different foundation vibrations on dynamic response of ground surface

动力基础在现代工业中有着较为广泛的应用,同时在其运行过程中也会对周边的环境产生振动影响。通过在室内自建大型模型槽,共浇筑了16个不同形状和材料的基础,先通过弯曲-伸缩元试验测试了砂土的动力参数,然后进行了不同形状、不同刚度和不同埋置深度等条件下的单个基础和相邻基础振动试验,分析了其振动传播特征和规律,并将试验结果和已有文献进行了对比。研究结果表明,振源的波形和频率对基础振动影响明显;单个条形基础引起的土体表面速度幅值最大,正方形基础次之,圆形基础最小;随着基础刚度的提高、基础高度增加和基础埋深的减小,土体中测点竖向振动速度幅值呈减小趋势。随着两相邻基础中心间距的增大,土体中测点竖向振动速度幅值在减小;与单个基础振动相比,两基础相互作用时,砂层振动速度幅值整体衰减特征与单个基础距振源一定距离处的振动速度幅值衰减更为相似。研究结果可以为动力基础的优化设计以及周边环境的振动防护提供参考。

Dynamic foundation is widely used in modern industry,and it can produce vibration influence on the surrounding environment in its operation process. Through constructing a large model slot indoor,16 foundations with different shapes and materials were poured. Then dynamic parameters of sand soil were measured with a bender-extender element test. Vibration tests for a single foundation and two adjacent foundations under conditions of different shapes,stiffnesses and buried depths were conducted,respectively. Their vibration propagation features and law were analyzed.The test results were compared with those in existing literatures. The results showed that the wave form and frequency of vibration sources obviously affect foundation vibration; vibration velocity amplitude of soil for a strip foundation is the maximum,that for a square one is the second large,and that for a cylinder one is the smallest; the vertical vibration velocity amplitude of measured points in soil decreases with increase in stiffness and height of foundations and decrease inburied depth of foundations; the vibration velocity amplitude of measured points in soil decreases with increase in the distance between two adjacent foundation centers; compared with a single foundation vibration,the overall attenuation characteristic of sand layer vibration velocity amplitude when two foundations interact is similar to the vibration velocity amplitude attenuation feature at the point on the single foundation with a certain distance from vibration source. The results provided a reference for the optimization design of dynamic foundations and the vibration protection of surrounding environment.