Dynamic Response Analysis Of Xi'an Drum-Tower Under Subway And Ground Traffic Vibration

In recent years,with the progress of science and technology,the transportation industry has been rapidly developing While bringing convenience to the residents and the society,the rapidly developing transportation has also caused many safety issues and environmental problems such as the deformation of ground surface and the tilt or collapse of surrounding buildings caused by traffic vibration.At the same time,the reciprocating traffic load may cause fatigue damage to the cultural heritage buildings along the road,which could reduce its overall stiffness and overall bearing capacity.Therefore,to assess the impact of traffic vibration on these cultural heritage buildings of high historical value,this thesis takes Xi'an Drum-Tower as the research object to conduct a comprehensive study in the vibration response to ground traffic,the dynamic characteristics of ground traffic,and the vibration response to underground traffic by combining field vibration test,theoretical analysis and finite element numerical simulation method.A vibration assessment is further conducted based on relevant national standards,which could provide a theoretical basis for the site selection of Xi'an metro line 6 line,and the life extension for Xi'an Drum-Tower.The main research contents of this thesis are as follows:(1)The ground traffic vibration test of Xi'an Drum-Tower was carried out,and the dynamic response of Xi'an Drum-Tower to ground traffic vibration was analyzed.After that,based on relevant standards,a vibration assessment was conducted for the Drum-Tower.(2)Based on the field vibration test results,the time-domain and frequency-domain analysis of the test signal was carried out by using the random vibration theory.Also,the propagation law of ground traffic vibration was studied,and the dynamic characteristics of Xi'an Drum-Tower(natural vibration frequency,mode,damping ratio)were obtained through the modal analysis of the vibration signal.(3)According to the structural characteristics of Xi'an Drum-Tower,different types of units were used in ANSYS software to simulate the mechanical properties of column bases,tenon joints and bracket sets,and then the finite element models of Xi'an Drum-Tower base,wood structure and overall structure can be established.(4)The modal analysis of the finite element models of Xi'an Drum-Tower base,wood structure and overall structure were carried out respectively.The rationality of the model was verified by comparing the simulation results and the measurement data.By comparing the simulation results of these three models,it shows that the self-vibration frequencies of the first four orders of the whole structure are close to that of the upper wood structure,while the frequencies for higher orders are much closer to that of the lower high platform.In contrast,the vibration modes for the first three orders of the whole structure are close to the modes of the upper wood structure,and the modes for higher orders are even closer to that of the higher base.As a result,the existence of high base will affect the dynamic characteristics of Xi'an Drum-Tower.(5)A three-dimensional finite element model of soil-structure was established,and the dynamic response of Xi'an Drum-Tower under different speeds and operating modes of metro line 6 was analyzed by numerical simulation.Moreover,the dynamic response of Xi'an Drum-Tower and its propagation law for vibration response were obtained,which were used to carry out a pre-evaluation for the effect of metro line 6 on Xi'an Drum-Tower according to the national standards.