Research On Urban Earthquake Disaster Evaluation Based On Active Faults

Earthquakes are the first of disasters,and the damage and losses caused by them are becoming more and more serious for modern cities.The current level of science and technology cannot yet accurately predict the arrival of an earthquake.How to effectively assess the possible losses caused by an earthquake and reduce the damage caused by the earthquake has always been an important issue.In this paper,the active faults of the Tanlu fault zone are taken as the research background,and the hazard evaluation and disaster prediction research of the active faults on the large cities along the faults are carried out.Based on the refined evaluation of the seismic hazards of active faults with potential earthquake risk,based on the results of the seismic motion zoning,considering the randomness of the earthquake and the randomness of the structure,select representative typical civil buildings for development based on the performance-based structural vulnerability analysis,the disaster types and specific indicators of reinforced concrete buildings based on active faults were summarized and proposed.Combined with the evaluation results of the potential seismic disasters of active faults carried out in the main damage areas of the faults mentioned above,further research and suggestions for urban disaster prevention and mitigation were proposed.The main content includes the following aspects:(1)Based on geological prospecting data,on-site drilling data,soil wave velocity measurement results and historical seismic data,the stratified velocity model of the underground soil layer structure of the research target city was established;and then from the research target city history M_w4.0?7.5 Level seismic data,analyzed the characteristics of active faults,established a three-dimensional source model that conformed to the geological structure of the research target city,performed three-dimensional ground motion simulation calculations to obtain the broadband seismic field in the target area,that is,apply the research target city Tanlu fault zone Ground motion waveform data.(2)A model of typical reinforced concrete frame structure was established by the structural finite element analysis software SAP2000,and a total of five structural models of four,six,seven,eight,and ten floors were constructed.The seismic simulation calculations at different locations were used 70 seismic waves were used as ground motion input,and a total of 350 calculation samples of 5 structural models were analyzed for time-history response.(3)The disaster indicators of reinforced concrete buildings based on active faults were proposed,the method for determining the structural seismic damage index was established,the structural vulnerability matrix was constructed,and the structural seismic damage index and its corresponding ring-breaking grade were calculated.(4)According to the correlation between different ground motion intensity and structural damage index and damage level,based on the simulated PGA distribution map of the ground acceleration peak of the Tanlu fault zone in the study target city,the main damage area under the potential earthquake of the active fault was developed.The typical structure of earthquake disaster zoning drew the predicted disaster assessment map of potential earthquakes in different levels of the disaster zone and the research target city Tanlu fault zone.According to the disaster assessment map to predict the damage state of this type of building structure in the target area under different peak ground acceleration ranges,the building could be repaired and reinforced in advance and the possible disaster in the event of an earthquake in this fault could be estimated.