基于现代原位测试CPTU的土体液化势统一评价方法  

Unified evaluation method for soil liquefaction potential based on modern in-situ piezocone penetration tests

作　　者：段伟 蔡国军[2,3] 刘松玉[2] 赵泽宁 董晓强[1] 陈瑞锋 DUAN-Wei;CAI Guo-jun;LIU Song-yu;ZHAO Ze-ning;DONG Xiao-qiang;CHEN Rui-feng(College of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Institute of Geotechnical Engineering,Southeast University,Nanjing 211189,China;School of Civil Engineering,Anhui Jianzhu University,Hefei 230601,China)

机构地区：[1]太原理工大学土木工程学院,山西太原030024 [2]东南大学岩土工程研究所,江苏南京211189 [3]安徽建筑大学土木工程学院,安徽合肥230601

出　　处：《岩土工程学报》2022年第3期435-443,I0003,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52108332,41877231,42072299);中国博士后科学基金项目(2021M702421)。

摘　　要：静力触探(CPT)测试是国际上常用的砂质土液化判别技术,但无法反映孔隙水压力(孔压)对液化行为的影响。能够测试孔压的现代原位测试技术孔压静力触探(CPTU)对砂质土、粉质土具有更高的辨识度和灵敏度,因此在砂质土、粉质土液化评价方面具有独特的优势。通过编译的CPTU液化案例数据库,在简化应力框架下,通过粒子群优化核极限学习机算法、稳健搜索技术和非线性拟合优化分析建立了基于CPTU测试参数的液化阻力比(CRR_(7.5))模型,该模型包括修正的锥尖阻力(qt1N)和土类指数(I_(c,BJ));其中I_(c,BJ)采用Jefferies和Davies提出的形式,包含了孔压参数比(B_(q))。这样所提模型中土壤类型信息直接包含在液化判别公式中,无需根据土壤细粒含量进行贯入阻力的修正,更直接、更符合力学框架,适用于砂质土、粉质土等较广范围的土体;并通过内含Bq的土类指数I_(c,BJ)将砂质土和粉质土液化判别统一起来。最后用中国唐山地震液化案例证明所提模型的准确性和优越性。The cone penetration test(CPT)is a commonly used technique to identify the liquefaction of sandy soil in the world but it cannot reflect the influences of pore water pressure(pore pressure)on the liquefaction behavior.The piezocone penetration test(CPTU),a modern in-situ test technique,can measure pore pressure,and has high identification and sensitivity to sandy soil and silty soil,so it has a unique advantage in liquefaction evaluation of sandy soil and silty soil.In this study,a liquefaction resistance ratio(CRR_(7.5))model based on CPTU test parameters is established under the simplified stress framework through the particle swarm optimization(PSO)-kernel limit learning machine(KLEM)algorithm,robust search technology and nonlinear fitting optimization analysis.The model includes modified cone resistance(qt1N)and soil behavior type index(I_(c,BJ))as per Jefferies and Davies,including the pore pressure ratio(B_(q)).In this way,the soil type information in the proposed model is directly included in the liquefaction discrimination formula,and it does not need to modify the penetration resistance according to the content of soil fine content,which is more direct and more consistent with the mechanical framework,and is suitable for a wide range of soil,such as sandy soil and silty soil.The liquefaction discrimination of sandy soil and silty soil is unified by the I_(c,BJ) with the inclusion of Bq in the formulation.Finally,the accuracy and superiority of the proposed model are proved by a case study of Tangshan Earthquake liquefaction in China.

关 键 词：孔压静力触探 粉质土 液化 土类指数 孔压参数比 

分 类 号：TU413[建筑科学—岩土工程]