不同排数新型空沟屏障隔振效果研究

Vibration isolation efficiency of new open trenches with different cross-sectional shapes and different rows number

结合振动波在土介质中的传播特性,在传统矩形空沟的基础上,设计6种不同截面形状的新型空沟。通过有限元建立各种新型空沟在不同面积、不同空沟排数及不同截面形式等工况下的隔振模型,研究各新型空沟在均匀、各向同性的弹性半空间下对地表稳态垂直简谐激励的隔振效果,从而探索如何通过改变波的传播方向、削弱波在原方向上的传播能力等措施,提高空沟的隔振效果。数值分析结果表明:(1)新型截面空沟在沟后绝大多数位置的主动隔振效果优于传统矩形空沟。当截面斜边设置在靠近振源侧时,更有利于提高主动隔振效果,其中右侧直角梯形截面空沟的主动隔振效果与传统矩形空沟相比,沟后平均竖向隔振效果可提高10.2%,水平隔振效果可提高8.4%;(2)增加空沟的排数能有效改善各截面形状空沟的隔振效果,但是当排数超过2排时,继续增加空沟排数对水平方向主动隔振及竖向被动隔振效果的改善不显著;(3)增加截面面积未能有效提高空沟的隔振效果,相反,在一定程度上反而减弱隔振效果。

Combining the propagation characteristics of the vibration wave in the soil medium,on the basis of traditional rectangular open trench,six new open trenches with different cross-sectional shapes are designed.Vibration isolation models with various section shapes,rows of open trenches and section area were established using finite element method,study the vibration isolation efficiency of new open trenches on the surface static vertical harmonic excitation,and explore how to improve the vibration isolation efficiency of the open trench by changing the wave propagation direction and weakening the wave propagation.The results show that:(1)The isolation efficiency of six new open trenches with different section shapes at most positions behind the trench is much better than that of the traditional open trench,especially when the inclined-side of new section locates nearby the excitation source.The average active vibration isolation efficiency of trapezoidal open trench with right-angle side nearby the excitation source is 10.2%and 8.4%higher in vertical and horizontal directions,respectively,than that of traditional rectangular open trench.(2)Increasing the rows number of open trench can improve the vibration isolation efficiency of the open trenches of various section shapes,however,the improvement of horizontal active vibration isolation and vertical passive vibration isolation is not significant by increasing the rows when the rows number exceeds two;(3)The increases in the section area does not effectively improve the vibration isolation efficiency of the open trench,on the contrary,the isolation efficiency could be decreased.