基于CPTu数据的阳江海域黏土循环强度评价方法研究  

Evaluation Method for Cyclic Strength of Marine Clay in Yangjiang Offshore Area Based on CPTu Data

作　　者：毛健伟 高尚[1] 吴琪[1] MAO Jianwei;GAO Shang;WU Qi(Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 211816,China;Shanghai Sumu Exploration Technology Co.,Ltd.,Shanghai 201702,China)

机构地区：[1]南京工业大学岩土工程研究所,江苏南京211816 [2]上海苏牧探测技术有限公司,上海201702

出　　处：《防灾减灾工程学报》2025年第2期317-328,共12页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(52378346)资助。

摘　　要：在堤坝、海上风力发电机、海底管线、海上石油平台、防波堤等海洋工程的设计与稳定性分析时,海床地基土的循环力特性及其评价方法是重要科学问题。为了系统探究海洋黏土的循环强度及其评价方法,对阳江海域黏土开展了不排水循环三轴试验和原位孔压静力触探试验CPTu。本研究的主要目的是为海上风电场的快速发展提供更可靠的岩土勘察指导。试验发现:海洋黏土的循环特性与陆域福建标准砂有显著差异。海洋黏土在循环荷载作用下以受拉破坏为主;循环荷载作用下试样的双幅轴应变(ε_(da))存在缓慢-急剧和快速-平稳两种发展模式,ε_(da)与循环次数N的幂率、超静孔压比与循环振次比N/NL的幂率均符合双曲线关系;分析了现有基于CPTu数据的液化判别方法在原状海洋细粒土中的适用性,基于现场与室内单元土体应力条件的相关性,建立了基于CPTu数据和埋深H的海洋黏土循环强度的评价方法。The cyclic force characteristics of seabed foundation soils and their evaluation methods are recognized as critical scientific issues in the design and stability analysis of marine engineering structures such as dikes,offshore wind turbines,subma-rine pipelines,offshore oil platforms,and breakwaters.To systematically investigate the cyclic strength of marine clay and its evaluation method,undrained cyclic triaxial tests and in-situ cone penetration test CPTu were conducted on clay from the Yangjiang offshore area.The primary objective of this study is to provide more reliable geotechnical investigation guidance for the rapid development of offshore wind farms.The results showed that the cyclic characteristics of marine clay significantly differed from those of onshore Fujian standard sand.Marine clay mainly exhibited tensile failure under cyclic loading.The double-amplitude axial strain(ε_(da))of samples under cyclic loading showed two development patterns:slow-sudden and rapid-stable.The power-law relationship between ε_(da) and the number of cycles(N),and that between excess pore pressure ratio and cyclic ratio(N/NL)conformed to a hyperbolic relationship.The applicability of existing liq-uefaction evaluation methods based on CPTu data for undisturbed marine fine-grained soils was analyzed.Based on the correlation between field and laboratory stress conditions of unit soil,an evaluation method for the cyclic strength of ma-rine clay was developed using CPTu data and burial depth(H).

关 键 词：海洋黏土 循环强度 原位孔压静力触探 孔压 轴向应变 

分 类 号：TU443[建筑科学—岩土工程]