硬土层地基破坏模式及承载能力有限元分析

Research on Foundation Damage Modes and Bearing Capacity in Hard Soil with Finite Element Method

王楠 吴建政 徐永臣 黄忠平 朱龙海

WANG Nan WU Jianzheng XU Yongchen HUANG Zhongping ZHU Longhai

中国海洋大学海洋地球科学学院, 山东青岛 266100; 中国海洋大学海底科学与探测技术教育部重点实验室, 山东青岛 266100; 中石化集团胜利油田海洋钻井公司, 山东东营 257000

College of Marine Geosciences, Ocean University of China, Qingdao Shandong 266100, China; Key Lab of Submarine Geosciences and Prospecting Techniques Ministry of Education, Ocean University of China, Qingdao Shandong 266100, China; SINOPEC Shengli Offshore Drilling Company, Dongying Shandong 257000, China

存在硬土层的层状地基承载能力分析是自升式平台插桩分析的关键问题。目前对于成层土地基的极限承载力往往采用近似的方法进行计算,对地基土的破坏机制以及中间荷载下土体的应力、应变情况等问题未得到很好的解决应用有限元法(FEM)对自升式平台在硬土层地基中插桩时地基土的破坏模式和承载能力进行了分析,研究表明,B/H越大,下伏软土层越容易发生塑性破坏,极限承载力明显下降,当B/H<0.3时可以忽略下伏软土层对地基承载力的影响有限元法与3:1扩散法计算的地基极限承载力结果十分接近,通过对某平台就位实例的分析表明,有限元法分析结果与实测结果较为吻合。

The bearing capacity of hard soil shell over a layered foundation is the key for calculation of penetration of jack-up leg footing. Currently, the ultimate bearing capacity of layered foundation is usually calculated with approximation method. With this approximation method,the damage modes and the stress of foundation under middle load can not been solved fully. The Finite Element Method has been used for simulating the damage process of foundation. The study results reveal that the plastic damage of soft stratum occurs more easily with the increasing of B/H value,and the ultimate bearing capacity reduces obviously. The soft stratum should not influence the ultimate bearing capacity of foundation when the numerical value of B/H is less than 0.3. Results show that the Finite Element Method matches well with the method of 3:1 Expansion Angle. Through analysis on a penetration example of jack-up leg footing, the analyzing results with Finite Element Method are coincided with the actual measured results.

胜利油田海洋钻井公司重点科技攻关项目"胜利海区地基上对自升式平台桩基作用的响应研究"(编号:GKZ1215)

https://doi.org/10.3969/j.issn.1008-2336.2012.04.088