Research On The Effect Of Vibration Isolation Barrier For Diaphragm Wall Under Subway-Induced Vibration

With the vigorous urbanization of China comes population booming and worsening traffic load.As a large-scale,fast,punctual and convenient transportation mode,urban rail transit is characterized by low energy consumption and less pollution.In view of the requirements of urban construction planning,road transportation and rail transit projects often take place close to or even underneath pass buildings,which leads to more serious vibration problems.Moreover,metro networks are also expected to grow along the trend of higher distribution density and faster development in the foreseeable future.While this will bring greater convenience to transportation,the presence of metro-induced vibrations will also only become more apparently felt by everyone.Due to the multitude of factors limiting the effectiveness of isolations at vibration sources and target locations,a lot more focus has been placed on researching the vibration isolation methods along the propagation path.In light of this,this paper adopted theoretical analysis,field measurement and numerical simulation to analytically explore the effects of vibration isolation barriers for diaphragm wall under metro-induced vibration,primarily covering the following contents.1.The existing research results are systematically collected and collated.Based on the vibration wave theory,the vibration propagation and attenuation law in soil are studied,and the mechanism of barrier vibration isolation is revealed,which provides a theoretical basis for the design of diaphragm wall vibration isolation barrier.2.Through the field measurement of the vibration acceleration of the soil in front of and behind vibration isolation barriers for tunnel side walls and diaphragm walls,the test results of various measuring points were compared.The propagation and attenuation patterns of metro-induced vibration in soil were then explored.The time-domain analysis show that the peak attenuation amplitude of the measured vibration acceleration tend to be large in areas close to the vibration source,but flat in areas far from the vibration source.Moreover,the spectrum analysis also help conclude that the high-frequency component can be attenuated rapidly during propagation through the soil stratum,while the low-frequency component still propagates very effectively through the stratum.3.A three-dimensional finite element numerical model was established to obtain the numerical analysis results.The feasibility of finite element software MIDAS GTS NX in dynamic analysis is verified by comparative analysis of field measured data.4.MIDAS GTS NX was employed to analyze how the thickness,depth,location and stratum properties of vibration isolation barriers for diaphragm walls can influence the quality of vibration isolation.Based on the understanding of these relationships,design and construction suggestions for real life projects were put forward.