The App Development For Designing Periodic Pile Barriers To Attenuate Ambient Vibration

As an effective measure to attenuate ambient vibration,pile barriers are widely applied in engineering.However,the majority of engineers design pile barriers on the basis of engineering experience at present and result in that some pile barriers not only failed to reduce vibration,but also magnify the vibration.The phenomenon is not difficult to explain by characteristics of attenuation zones.Because of engineers not understanding characteristics of attenuation zones of periodic structures,once the main vibration frequencies that would like to be isolated are not located on the attenuation zones of pile barriers designed by engineers,the failure of pile barriers is inevitable and it even amplifies the vibration effect.In view of this,for the convenience of engineers designing pile barriers reasonably,an App is developed in the paper.Specifically,when engineers know the main frequencies of ambient vibration isolated and the site soil parameters,they can directly get the values of pile radius and pile spacing by using the App so as to ensure that the designed pile barriers can attenuate vibration accurately and effectively.The main research contents are as follows:(1)Based on periodic structure theory,attenuation zones of four kinds of periodic pile barriers are calculated aim at solid piles and hollow piles arranged in square,and solid piles and hollow piles arranged in hexagon,and some influential factors on attenuation zones are discussed.In addition,numerical simulation models of two periodic pile barriers are established to verify the feasibility of using the four kinds of pile barriers to attenuate ambient vibration.(2)Design the user interface and function realization of the App.Adhere to the principle of simple and easy to operate,the functions of designing pile barriers and simulating vibration isolation are realized.Specifically,when users input the upper and lower boundary values of the main frequencies of environmental vibration isolated and site soil parameters,and then select the type of pile barriers they want,App can quickly complete relevant calculation and output the suggested values of pile radius and pile spacing of concrete piles designed.The numerical simulations of vibration isolation effect of 1-4 rows piles are completed and output the ratio of vibration isolation effect of piles in different rows,which provides a reference for the users to choose the number of pile rows reasonably.(3)The realization of pile barriers design is one of the difficulties in the paper.The common finite element analysis software can only obtain the forbidden band of frequency under the condition of given the parameters of piles,but the problem of pile barriers design is to obtain the parameters of piles under the condition of given the forbidden band of frequency,which is equivalent to the inverse problem.According to the conventional idea,the pile parameters are established and COMSOL is repeatedly called for attenuation domain calculation,which is bound to result in slow App running speed.Based on the response surface model,the paper presents a quick calculation method for periodic piles,which greatly improves its running speed.(4)In order to facilitate users to better grasp the application method of the App,five application examples of the App are listed.The examples include both successful design cases and corresponding modification Suggestions or guidance for failed design cases.The App developed in this paper can be used for the design of pile barriers to attenuate ambient vibration,providing a new technical support for designers to design pile barriers reasonably.