Micro Vibration Influence Analysis Of Surface Buildings Caused By The Subway Blasting

The development of modern city lead to city traffic problem protrude increasingly,subway obtains more and more favour as a perfect transportation. At the same time, theimpact on buildings caused from the excavation blasting in the process of the subwayconstruction has caused the attention. Therefore, it has became a challenge for blastingworkers to solve, that the research about the mechanism of production, the characteristics ofdiffuse and attenuation of blasting seismic wave and the dynamic response of buildings, andthen find out the reasonable measures to control it.In view of this, this article takes the related theories and research methods of blastingvibration, and the vibration monitoring project of the huaquan tunnel excavation blasting ofdalian subway project as basis, and then combines with a large number of actual blasting data,obtains some research findings. The main researches and findings are as follows:First of all, the thesis researches the generating mechanism of blasting seismic wave andits propagation and decay laws, summarizes and sums up the main influence factors ofblasting seismic effect, namely: blasting three elements-amplitude, frequency and time ofduration. And it gets the characteristic properties of blasting seismic wave which comparedwith natural seismic wave. At the same time, the thesis introduces the dynamics analysismethods of the blasting vibration response of buildings, mainly to the vibration modedecomposition response spectrum method and time history analysis.In the second place, the thesis obtains the Sadaovsk model which reflects the blastingvibration intension of the huaquan tunnel that computed by regression analysis method.It willbe relatively exact and reasonable for this model to direct the subsequent blasting.In the third place, dynamic response analysis of a four-flour frame structure by blastingseismic action is done by finite element program ANSYS based on the measured blastingseismic waves. It obtains the following conclusions after the analysis:(1) The vibration response in vertical direction of frame structure plays a leading rolewhen under the action of blasting seismic waves of vertical direction, and the amplificationeffect of blasting vibration in vertical direction is obvious.(2) The blasting vibration response of structure is proportional to the amplitude of theinput blasting seismic waves.(3) Dominant frequency of blasting seismic waves has a large impact on vibrationresponse of structure, and the vibration response of structure will be more intense while thedominant frequency is close to the natural frequency of vibration of structure.(4) The time of blasting seismic waves has little impact on the vibration response ofstructure. At last, the thesis also discusses the safety control measures of the blasting vibrationresponse of buildings structure and gives some proposal.