结构性土中静力触探孔压消散的大变形模拟  

Large deformation simulation of pore pressure dissipation during penetration of piezoncone in structured soil

作　　者：孙淼军 谢雅囡 王栋[2] SUN Mao-jun;XIE Ya-nan;WANG Dong(Powerchina Huadong Engineering Corporation Limited,Hangzhou,Zhejiang 311122,China;Shandong Engineering Research Center of Marine Exploration and Conservation,Ocean University of China,Qingdao,Shandong 266100,China)

机构地区：[1]中国电建集团华东勘测设计研究院有限公司,浙江杭州311122 [2]中国海洋大学海底建设与保护山东省工程研究中心,山东青岛266100

出　　处：《岩土力学》2024年第11期3416-3422,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42025702,No.52394251)。

摘　　要：静力触探试验被广泛用于确定原状土的工程性质。黏性土中探头的连续贯入引起超静孔压积累,贯入停止后孔压逐渐消散。在结构性粉质黏土、黏质粉土或粉土中,贯入过程可能发生部分排水现象,导致其后续的孔压消散响应相较于不排水贯入时更复杂。将结构土剑桥模型引入有效应力形式的大变形有限元方法,模拟结构性土中静力触探试验的贯入-消散全过程,得到部分排水或不排水贯入后超静孔压消散曲线的归一化表达。通过与现有离心机试验对比,验证了大变形方法的可靠性。大量变动参数分析发现,可以合理忽略土体类型、土体初始结构和消散深度对归一化消散曲线的影响,该曲线可用于确定有效固结系数,进而预测常规固结系数。Piezocone penetration tests are widely used to determine the engineering properties of in situ soils.Continuous penetration of the probe in cohesive soils leads to the accumulation of excess pore pressure,which gradually dissipates after the penetration is stopped.In structured silt-clay,clayey silt or silty soils,partially drained may occur during the penetration process,leading to more complex pore pressure dissipation responses following penetration compared to those under undrained conditions.To simulate the entire“penetration-dissipation”process during piezocone penetration and dissipation tests in structured soil,Structured Cam-Clay model is incorporated into the large deformation finite element method within the framework of effective stress analysis.A normalised expression for the dissipation of excess pore pressure after partially drainage or undrained penetration is obtained.The reliability of the large deformation method is verified by comparing with the existing centrifuge tests.A large number of parametric studies have revealed that the effects of soil type,initial soil structure and dissipation depth can be reasonably neglected on the normalised dissipation curve,which can be used to determine the operative consolidation coefficient and subsequently predict the conventional consolidation coefficient.

关 键 词：静力触探 结构土 有限元 部分排水 超静孔压 

分 类 号：TU442[建筑科学—岩土工程]