粉土中吸力式桶形基础沉贯及抗拔特性试验研究  

Model tests on penetration and pullout of suction caissons in silt

作　　者：朱斌[1,2] 孔德琼[1,2] 童建国[3] 孔令刚[1,2] 陈仁朋[1,2] 

机构地区：[1]浙江大学软弱土与环境土工教育部重点试验室,浙江杭州310058 [2]浙江大学岩土工程研究所,浙江杭州310058 [3]浙江省电力设计院,浙江杭州310012

出　　处：《岩土工程学报》2011年第7期1045-1053,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50979097);国家"863"高技术研究发展计划资助项目(2007AA05Z427);浙江省重点创新团队支持计划项目(2009R50050)

摘　　要：吸力式桶形基础的负压沉贯控制和抗拔承载力确定是海洋钻井平台和海上风电机组多桶基础以及深海吸力锚基础设计和施工中的关键问题。通过室内大比例模型试验研究了吸力式桶形基础在饱和粉土中的负压沉贯及抗拔特性。负压沉贯试验结果表明负压并不能明显减小吸力式桶形基础在粉土中的沉贯阻力,基于CPT试验结果可较为准确地预估沉贯施工所需负压,从而确保沉贯的顺利实施和防止沉贯过程中地基发生管涌破坏。不同加载速率下的上拔试验结果表明存在一临界加载速率,当实际加载速率超过该临界值后,加载速率对吸力式桶形基础的抗拔特性影响较小。结合桶体及桶外土体的变形,提出了粉土地基中不同受力状况下吸力式桶形基础的抗拔承载力计算方法。Suction penetration and ultimate uplift capacity are the two key issues in the design and construction of suction caissons used as suction anchors in deep water or multi-caisson foundations for the offshore platforms/wind turbines.A programme of large-scale model tests on a suction caisson is carried out in a large soil tank in Zhejiang University to study the behaviors of the caisson foundations during suction penetration and pullout.The test results of suction penetration show that the suction under the lid just has a slight influence on installation resistance of the caissons in silt,and the suction required to penetrate the caisson without soil piping is well predicted based on the results of CPT tests.The pullout tests with different loading rates are also carried out,and the results indicate that loading rate has little effect on the performance of the caisson foundation if a critical loading rate is surpassed.Based on the test results,the ultimate pullout capacities of the caissons in silt for different loading conditions are presented.

关 键 词：吸力式桶形基础 粉土 沉贯 抗拔 承载力 

分 类 号：TU432[建筑科学—岩土工程]