Liquefaction Judging Methods Based On Shear Wave Velocity In Bachu Earthquake Survey

Liquefaction disaster is the most significant one of the earthquake geological hazards, prevention and mitigation of liquefaction disaster is an important research topic in the geotechnical earthquake engineering, and liquefaction potential judging as an important reference method for the project seismic design have caught domestic and foreign civil engineering research and design staff's much attention. And proved, based on the field test data of different seismic liquefaction field survey to establish the liquefaction judging formula is the best and most direct way to develop the liquefaction predict.February 24, 2003 Bachu– Jiashi occurred Ms6.8 earthquake, there have been massive earthquake soil liquefaction problems, resulting in the destruction of farmland, road damage, building damage and disasters such as rivers, ditches Collapse , it is the largest emerging phenomenon of sand liquefaction in nearly 30 years since Tangshan, Haicheng earthquake in China. And for the in-depth understanding of the earthquake liquefaction, testing the reliability of existing methods and the development of liquefaction judging method provides new conditions.The basic characteristics of Bachu earthquake liquefaction are summarized based on the basis of earthquake field investigation, specifically to carry out site survey testing of earthquake liquefaction sites, use the SASW surface wave method to collect the Bachu earthquake shear wave velocity data, compared to The results of CPT and SPT and analyzed the reliability of the results of shear wave velocity, use the existing liquefaction judging formulas based on the shear wave velocity to analyze their suitability in Bachu earthquake liquefaction site, and establish a new liquefaction judging formula based on shear wave velocity for the Bachu region.The main contents of this dissertation include:(1)Summarizing the characteristics of the liquefaction damage in Bachu earthquake, by choosing the different situ test equipment, specially designed the survey program for the liquefaction, and completed the wave velocity test of 36 investigation points.(2) Describing the advantages of shear wave velocity in situ testing method, analyzing the characteristics of the shear wave velocity in Bachu earthquake field, comparing with cone penetration test and standard penetration test results of two tests, analyze the reliability of the shear wave velocity data, to confirm the reliability of this shear wave velocity data collected by surface wave method.(3) Analyzing the Bachu earthquake shear wave velocity data, using five of the existing soil liquefaction judging formulas based on shear wave velocity to analyze their regional applicability in the Bachu area, proposing the necessity of establishing the regional liquefaction judging formula based on share wave velocity in Bachu area.(4) Comprehensively comparing the established way of both domestic and international liquefaction judging formulas which based on situ site investigation of the liquefaction sites. With the practical engineering requirements, establishing the basic model of regional liquefaction judging method based on the shear wave velocities of Bachu area, by using optimization methods to determine the parameters, proposing the liquefaction judging formula of shear wave velocity based on Bachu seismic survey, giving the success rate of liquefaction judgment, and analyzing the misjudgment points in the liquefaction judgment by using the new established formula.