基于2011年新西兰地震的CPT液化特征研究

2011年2月22日,新西兰第二大城市克赖斯特彻市附近发生Ms6.3级地震,震中位于克赖斯特彻市西南10km处,震源深度为5km.地震造成了大量的人员伤亡和经济损失,重建费用估计高达40亿新西兰元,得到共识是砂土液化为震害主因.此次地震,液化震害极为严重,喷砂冒水范围广泛分布于城市内外,引起大量次生灾害,地震也为砂土液...

Studies on liquefaction characteristics by CPT in 2011 New Zealand earthquake

On February 22, 2011, an M6.3 earthquake struck the city of Christchurch, the second largest city in New Zealand. The epicenter was located 10 kilometers southwest of Christchurch, and the focal depth was 5km. The earthquake caused a large number of casualties and economic losses. The reconstruction cost is estimated to be up to 4 billion New Zealand dollars. It was agreed that sand liquefaction was the main cause of the damage.In this earthquake, the liquefaction damage was extremely serious. The range of water spraying and sand emitting was widely distributed inside and outside the city, causing a large number of secondary disasters. The earthquake also provided a lot of valuable liquefaction data for the study of the characteristics of sand liquefaction, especially for testing and developing liquefaction evaluation methods. This paper collects the survey data of 132 survey points after the earthquake, including static cone penetration test data, peak acceleration, groundwater level, and so on. Through the study of the data, the acceleration distribution characteristics, groundwater level distribution characteristics, and sand burial depth distribution characteristics of the earthquake were obtained. The existing CPT liquefaction evaluation method in Chinesecode was tested, andthe results show that the PGA of the liquefied sites is mainly distributed around 0.5g-0.65g and the liquefaction layer is mostly within 5m. The CPT liquefaction evaluation method in Chinesecode had obvious errors for the sand layers below 10m. It was also found that multiple liquefaction layers were located below 20m in thisearthquake. For this depth, there is no liquefaction evaluation method in our country.