基于标贯试验的含细粒砂土液化概率判别新模型  

A New SPTBased Model for Liquefaction Probability Discrimination of FineGrained Sandy Soil

作　　者：李萍萍 赵少飞[1] 鲍俊文 刘子源 LI Pingping;ZHAO Shaofei;BAO Junwen;LIU Ziyuan(North China University of Science and Technology,Beijing 101601)

机构地区：[1]华北科技学院,北京101601

出　　处：《防灾减灾工程学报》2024年第5期1133-1139,共7页Journal of Disaster Prevention and Mitigation Engineering

摘　　要：含细粒砂土在自然界中普遍存在,在应用标准贯入试验判别砂土液化时,通过对标贯击数进行修正反映砂土中细粒含量的影响。以国内外25次大地震收集整理的230组实测数据为基础,利用Idriss和Boulanger、Cetin等和NCEER分别提出的三种标贯击数修正公式,通过逻辑回归建立三个液化概率计算模型,对比三个模型,Cetin等修正公式相应的液化概率计算模型拟合优度和预测准确性最好。根据中国《岩土工程勘察规范》(GB 50021-2001)和美国《标准贯入测试和对开管取样的标准试验方法》(ASTM D1586-11)的标贯击数转换关系,推导出适合于中国规范的含细粒砂土液化概率判别新模型。回判分析表明,新模型对基于美标的实测液化数据具备良好的判别性能。利用台湾集集地震实测288组数据,比较了新模型与建筑抗震设计规范(GB 50011—2010)(以下简称“建规法”)判别方法。结果表明,新模型的总体判别成功率94.1%高于建规法77.4%,其中液化场地判别成功率93.9%略低于建规法的99.4%,但非液化场地成功率86.3%远远高于建规法判别成功率48.4%。Fine-grained sandy soil is widespread in nature.When the standard penetration test(SPT)is used for liquefaction discrimination of sandy soil,the influence of fine grain content in sandy soil is reflected by modifying the standard penetration blow count.Based on 230 sets of measured data collected and collated from 25 major earthquakes worldwide,using three correction formulas for SPT blow counts proposed by Idriss and Boulanger,Cetin et al.and NCEER,this study established three liquefaction probability calculation models using logistic regression.A comparison of the three models showed that the one based on correction formula proposed by Cetin et al.demonstrated the best goodness-of-fit and prediction accuracy.According to the conversion relationship between blow counts in the Chinese Code for Investigation of Geotechnical Engineering(GB 50021—2001)and Standard Test Method for Standard Penetration Test(SPT)and Split‑Barrel Sampling of Soils(ASTM D1586-11),a new model for liquefaction probability discrimination of fine-grained sandy soil suitable for the Chinese Code was derived.Back-analysis indicated that the new model performed well in discriminating liquefaction data measured using the American Standard.Using 288 sets of data from the Chi-Chi earthquake in Taiwan,the new model was compared with the discrimination method from the Code for Seismic Design of Buildings(GB 50011-2010)(hereinafter referred to as"Building Code method").The results showed that the overall discrimination success rate of the new model(94.1%)exceeded that of the Building Code method(77.4%),with a success rate of liquefaction sites of 93.9%,slightly lower than that of the Building Code method(99.4%),but the success rate of non-liquefaction sites(86.3%)was significantly higher than that of the Building Code method(48.4%).

关 键 词：液化判别 标准贯入试验 细粒含量 逻辑回归 

分 类 号：TU435[建筑科学—岩土工程]