Dynamic response of building structures with high-rise frames caused by blasting vibration at adjacent subway foundation pit

In order to ensure the safety and stability of the high-rise building adjacent to the blasting excavation process at the adjacent urban subway foundation pit, it is the key to analyze the dynamic response characteristics of the building structure under the action of blasting vibration.Based on the foundation pit engineering of Hongshan Road Station and Xiaohongshan Station of Wuhan Metro Line 8, this paper analyzes the attenuation law of blasting vibration along the surface of the foundation pit and its influence on the structure of the building through on-site blasting test and vibration test.Meanwhile with the application of the LSDYNA dynamic finite element method, the results of blasting test is used to verify the reliability of the numerical calculation model and parameters.The maximum single-stage control dose of foundation pit excavation blasting is proposed according to the safety control standard of blasting vibration of high-rise buildings.The calculation of dynamic numerical values under these working conditions is used to analyze the spatial distribution characteristics of blasting vibration velocity and dynamic stress of high-rise buildings and evaluate the safety and stability of adjacent high-rise frame buildings under blasting vibration.The results show that through the blasting experiment analysis, in the process of blasting vibration propagation, the high-rise building has the vibration speed amplification effect, and the top floor vibration speed is 1.19-1.26 times relative to the first floor magnification.Under the same dosage and different excavation depths, as the excavation depth increases, the vibration speed is mainly attenuated, and the high-rise building magnification will not be affected.By comparing the measured data with the numerical simulation results, the maximum error rate of the two is only 6.83%, indicating the reliability of the numerical model and parameters.The wave velocity transmission of high-rise buildings has obvious attenuation effect and amplification effect.The vibration of top floor increases with the increase of floor, and the wave velocity is first attenuated and then amplified.Fitting the empirical formula of peak vibration velocity attenuation based on field measurement, the maximum single-stage dose of on-site blasting can be controlled to 15 kg, which can guide the on-site safe blasting.