Verification Of Chinese Critera On Sand Liquefaction During Earthquakes

Considering earthquake damage history in recent decades, sand liquefaction has become a typical phenomenon of damage in various countries and undoubtedly caused huge losses on the national economy. A series of questions caused by sand liquefaction have also caught more and more attention of scholars from various countries. In seismic design for engineering, whether sand liquefaction will happen is a problem to be prior solved and discrimination of potential has become an important issue for scholars. During five decades of studying sand liquefaction, scholars has applied large number of field and laboratory tests, established discriminant of sand liquefaction potential based on different indexes and reached a better understanding of liquefaction mechanism. However, as a random event, parameters of earthquake is characterized by randomness and uncertainty, which lead to the fact that existed deterministic discriminance have to rely on experience means and certain defect exists in a same discriminance for different venues.In this paper, sand liquefaction mechanism and its effecting factors are discussed. According to standard penetration data in Tangshan earthquake, spot with a minimum standard penetration blow count is chosen and considered as the spot with a lowest strength, and then its data is used in the liquefaction criterion of Code for Seismic Design of Buildings to verify. For misjudgment point in the code, soil profile analysis is carried out in corresponding holes. Considering the situation that a wide range of misjudgment occurs in section with a seismic intensity of8, liquefaction SPT threshold that is more suitable for Tangshan earthquake is proposed. According to correspondence between SPT blow count and overburden effective stress, dividing line between liquefaction and non-liquefaction in section with a seismic intensity of7,8,9is given. In this paper, analysis is carried out according to data in section with a seismic intensity of10and sectional view of the holes is drawn.