Study On Empirical Prediction Model Of Train-induced Indoor Vibration In A Building

The current research on the law of the subway train-induced vibration propagation and attenuation inside and outside the building is not perfect.In order to solve this problem,this paper puts forward an empirical prediction model of the vibration transmission loss from the outside of the building to the inside the building through the study of the soil-building structure dynamic interaction under the subway train-induced vibrations environment.Based on this empirical prediction model,the vibrations of the indoor building can be quickly predicted.The prediction result includes the VL_Zmax and the acceleration level on the 1/3 octave band.Finally,the empirical prediction method is verified by a site test of a residential building along the Line 9 of Beijing Subway.The main work and conclusions are as follows:（1）The research status of building structural vibration prediction caused by subway is systematically summarized.The basic theory and calculation method of building vibration are expounded.（2）Site test was carried out around a 4-storey brick-concrete residential building along the subway,and models were established for calculation based on the background of the test project.The node coupling method,pe nalty function method,extended Lagrangian method,MPC method,pure Lagrangian multiplier method and hybrid algorithm are used to simulate the contact relationship between soil and structure.The result shows that the calculation result of penalty function method（or extended Lagrangian method）is the closest to the test result.（3）Considering the influencing factors such as the horizontal distance between the vibration source and the building,the depth of the vibration source,and the type of soil,the vibration reflection of the soil near the building and the law of vibration transmission loss from the building indoor and outdoor are analyzed in detail.The results show that the greater the reflection of the vibration wave by the building,the greater the vibration transmission loss inside and outside the building.（4）Considering the influencing factors such as the horizontal distance between the vibration source and the building,the number of floors of the building and the area of the rooms,a number of working conditions are set for simulation calculations.And the vibration transmission loss from the outside of the building to the inside of the first floor of the building is analyzed.Then an empirical prediction formula is fitted by MATLAB based on the numerical calculation results.The formula in this paper can not only predict the VLZmax in the first floor of the building,but also predict the acceleration level in the 1/3 octave band.（5）The empirical prediction formula of this paper is verified by a site test of the residential building along the Line 9 of Beijing Subway.The results show that the empirical prediction method in this paper is applicable.