有限元法在桩靴承载力计算中的应用  

Application of Finite Element Method in Calculating the Bearing Capacity of Pile Boots

作　　者：王楠[1,2] 朱龙海[1,2] 姜胜辉[1,2] 胡日军[1,2] 徐永臣[1,2] 

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266100 [2]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

出　　处：《海岸工程》2014年第3期36-46,共11页Coastal Engineering

基　　金：国家自然科学基金委员会青年基金项目--辽东浅滩潮流砂脊演化过程及响应机制(41106039)

摘　　要：自升式钻井平台插桩是地基土在桩靴荷载作用下发生连续的塑性破坏的动态过程,当地基极限承载力等于桩靴荷载时插桩完成。经典土力学极限承载力理论对土体潜在滑动面做了假设,无法有效分析土体内部的破坏过程。本研究应用有限元法(FEM)对插桩过程进行了模拟,得到地基土的破坏机制以及中间荷载下土体的应力、应变情况,通过和各理论公式计算的极限承载力进行对比分析,分析影响地基极限承载力的因素。研究表明,基础宽度与硬土层厚度的比值B/H越大,下卧软土层越容易发生塑性破坏,极限承载力明显下降,当B/H<0.286时,可以忽略下卧软土层对地基承载力的影响。Pitching pile of self elevating drilling platform is a dynamic process of continu-ous plastic damage of foundation soils in the pile shoe loads .When the ultimate bearing capacity of foundation equals to the load on pile boots ,the pile pitching is completed . Because the classical theory of limit bearing capacity of soil mechanics has made assump-tions to the sliding surface hidden in the soil body ,the damage process occurring inside the soil could not be analyzed efficiently .For this reason ,the finite element method （FEM ） is used to simulate the pile pitching process ,by w hich the failure mechanism of foundation soils and the stress-strain of subsoil body under a middle load are obtained . By comparing with the ultimate bearing capacity calculated by using different theoretical formulae ,the factors influencing the ultimate bearing capacity of foundation soils are analyzed .T he results reveal that the larger the B/H ratio is ,the easier the plastic dam-age occurs in the underlying soft stratum .As a result ,the ultimate bearing capacity re-duces obviously .When the value of B/H is less than 0 .286 ,the influence of the under-lying soft stratum on the ultimate bearing capacity of foundation soils can be ignored .

关 键 词：桩靴 有限元 极限承载力 

分 类 号：P752[天文地球—海洋科学]