南海某深水井场海洋黏土工程特性分析

Engineering Characteristics Analysis of Deepwater Well-site Marine Clay in South China Sea

为探究南海深水区域海洋黏土工程特性,基于多种室内土体强度测试方法对南海某平台场址高塑性海洋黏土强度特性进行了系统测试分析。量化了应变控制连续加荷固结试验(CRS)和标准固结试验(ODE)方法确定应力历史的差异;验证了基于单剪试验(SS)的SHANSEP试验方法在该海域的适用性,并结合原位应力状态和应力历史绘制了沿深度方向的强度剖面;基于k0固结三轴压缩/拉伸试验(Ck0UC/E)量化了土体强度各向异性;测试了高围压下土体不固结不排水抗剪强度;根据Ck0U和SS确定了土体的有效/总抗剪强度参数;整合分析了不同试验方法下土体归一化抗剪强度沿深度分布规律。成果可为南海深水海洋结构物基础设计提供工程地质参数测试分析方法和应用经验。

Multiple methods are employed to explore the deepwater marine clay engineering characteristics with high plasticity at one well site in south China sea. Based on the CRS and ODE tests, the differences of stress history are quantified. Test results indicate that the SHANSEP(Stress History and Normalized Soil Engineering Properties) method is suitable for the objective evaluation of offshore cohesive soils from the South China Sea, by which the strength profile along depth is described. The strength anisotropy is quantified by Ck0 UC/E tests and the unconsolidated undrained shear strength is tested under high confining pressure. Through Ck0 U and SS tests, the effective and total shear strength parameters are determined. Based on the research above, the distributions between normalized shear strength and depth under different methods are comprehensively analyzed. The results can provide engineering geological parameter analysis experience for the basic design of deepwater marine structures in the south China sea.