自由落体式球形贯入仪在硬-软黏土中的贯入响应  

Free falling sphere penetrometers in stiff-soft clays

作　　者：范晓亮 郑敬宾 王栋[1,2] FAN Xiaoliang;ZHENG Jingbin;WANG Dong(Institute of Marine Geotechnical Engineering,Ocean University of China,Qingdao 266100,China;School of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学海洋岩土工程研究所,山东青岛266100 [2]中国海洋大学环境科学与工程学院,山东青岛266100

出　　处：《海洋工程》2023年第1期48-56,共9页The Ocean Engineering

基　　金：国家自然科学基金资助项目(42172294,U1806230,42025702)。

摘　　要：自由落体贯入仪(free falling penetrometer,简称FFP)通过自由下落贯入土层中,由于其高效便捷的特性,越来越广泛地被应用于海底浅层土体原位勘察。采用耦合欧拉-拉格朗日(Coupled Eulerian Lagrangian,简称CEL)方法,进行了球形FFP在硬-软双层黏土中贯入的大变形有限元分析,考虑了土体的应变率和应变软化效应。与离心机试验、现场试验和数值模拟结果进行了对比,验证了模型的可靠性。分析了成层土对贯入过程的影响,发现FFP在贯入过程中上部硬黏土层形成空腔,且底部会伴随着土塞。通过广泛的变参数分析结果,拟合了球形FFP最终贯入深度与总能量之间的归一化表达式,建立了土体不排水抗剪强度、FFP直径和贯入速度与FFP在硬-软黏土层中最终贯入深度的关系。The free falling penetrometer(FFP)is increasingly being used in in-situ investigations of shallow seabed soils,and is convenient and efficient to operate by free-falling into the soil.The Coupled Eulerian-Lagrangian(CEL)approach was employed to perform large deformation finite element analyses for the penetration process of FFP in stiff-soft clay.The Tresca model considering strain rate effect and softening was used.Compared with the results of centrifuge tests,field tests and finite element analyses results,the capability and accuracy of the CEL approach were confirmed.The effect of stratified clays on the penetration process was analyzed,to find that the stiff-clay layer forms a cavity,and that the bottom of the FFP is accompanied by a soil plug.Based on the results of extensive parameter studies,the normalized expression between FFP final penetration depth and total energy was proposed.The final penetration depth of FFP in stiff-soft clay was predicted by the undrained shear strength of soil,sphere diameter and velocity.

关 键 词：自由落体贯入仪 原位测试 大变形有限元 贯入 硬-软黏土层 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]