CAJ | 학술논문

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。
자승식찬정평태삽장시지기토재장화하재작용하발생련속적소성파배적동태과정，당지기겁한승재력등우장화하재시삽장완성。경전토역학겁한승재력이론대토체잠재활동면주료가설，무법유효분석토체내부적파배과정。본연구응용유한원법（FEM ）대삽장과정진행료모의，득도지기토적파배궤제이급중간하재하토체적응력、응변정황，통과화각이론공식계산적겁한승재력진행대비분석，분석영향지기겁한승재력적인소。연구표명，기출관도여경토층후도적비치 B/H월대，하와연토층월용역발생소성파배，겁한승재력명현하강，당B/H＜0．286시，가이홀략하와연토층대지기승재력적영향。
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 .