Regional Site Classification Method Based On Multiple Factors

Site classification is the main basis to consider site effect in the prediction and rapid assessment of earthquake motion and earthquake damage in regions and even the whole country.The study on regional site classification method is of great theoretical significance and practical value for the establishment of site calibration model in the earthquake catastrophe insurance,earthquake early warning and intensity rapid report.In view of the good consistency of the macroscopic factors,such as topography,geology,geomorphology,site of equivalent shear wave velocity and category trends,this paper studies the relationship between topography,geology,geomorphology and equivalent shear wave velocity and overburden thickness of site classification indexes in China by collecting wave velocity and classification of engineering sites in Xinjiang,as well as topographic maps,geological maps and geomorphic maps.Then a macro site classification method by fusing various factors is established.The followings are the main work and achievements of this paper:1.The geological map,topographic map,geomorphic map,wave velocity and classifications of engineering sites in Xinjiang are collected and sorted out.The paper realizes the comprehensive management of site data digitization and classification in order to provide a data foundation for studying the relationship between topographical factors,geological factors and site classification indexes.2.Based on the topographic and site classification data of Xinjiang,the correlation between topographic slope and site classification indexes such as Vs30,Vs20 and overburden thickness was established,and a site classification method based on both topographic slope-Vs20 and slope-overburden thickness was proposed.A direct correspondence is shown between two-parameters step model method and the standard site classification indexes in China.This method doesn't need to rely on Vs30 and Vs20 conversion,which is more suitable for the classification of regional sites in China.The site classification registration revised by the inverse distance weight method is significantly higher than that of the slope-Vs30 model.3.Based on geological map and site classification data of Xinjiang,a site classification method based on the hardness of rock mass and combined with geological factors such as sedimentary origin and geological age is established.This paper mainly considers the corresponding relation between the hardness classification of geotechnical mass based on geological map and the classification standard of soil type and the wave velocity of geotechnical in Chinese code for Seismic Design of Buildings(GB50011-2010),which reduces the subjective experience of the method based on geological factors to some extent.4.Based on the study of the correlation between regional geomorphology,macroscopic topography,geological factors and site classification indexes,the multifactor fusion site classification method based on the four-level division principle of "geomorphology-rock hardness-sediment genesis-topographic slope" is established,and the site classification maps of Xinjiang and the whole country are compiled.In this paper,various factors such as geomorphology,topography and geology are integrated and coordinated to establish a site classification model based on the principle of whole to part and qualitative to quantitative.And the rationality and accuracy of regional site classification is revised to further improve.