基于梯度优化法的单桩竖向承载力可靠性研究  

Research on the Reliability of the Vertical Bearing Capacity of Single Pile Based on the Gradient Optimization Method

作　　者：武运磊[1] 武清玺[1] 戚佩奇[2] 戚桂宾 

机构地区：[1]河海大学力学与材料学院,江苏南京210098 [2]南京水利科学研究院江苏科兴工程建设监理公司,江苏南京210024 [3]山东省城乡建设勘察院,山东济南250031

出　　处：《人民黄河》2013年第6期138-140,共3页Yellow River

摘　　要：采用可靠度理论对钻孔灌注桩竖向承载力进行研究,并建立桩基承载力极限状态方程,运用FORTRAN语言按梯度优化法编写计算可靠度指标程序。针对某灌注桩承载力进行可靠度计算,并对影响单桩竖向承载力的基本因素进行敏感性分析,探讨计算模式不确定系数、极限摩阻力、桩端极限阻力、桩顶荷载对桩基可靠度的影响,结果表明:桩基穿越多层土时,桩侧土质越好,即极限摩阻力越大,对桩基承载力可靠性影响越明显,其极限摩阻力变异系数对可靠指标的影响也越显著;桩基可靠指标随着计算模式不确定系数、极限摩阻力、桩端极限阻力、桩顶荷载变异系数的增大而减小。The vertical bearing capacity of the bored pile was studied by using the reliability theory,and the limit state equation of pile foundation bearing capacity was established.Meanwhile,the calculation reliability index program was written by using the gradient optimization method in FORTRAN Language.Reliability of one bored pile was calculated,and the sensitivity analysis was adopted to study the influences of the basic factors that affect the bearing capacity,also the influences of the uncertainty factors of calculation model,the ultimate friction resistance,the ultimate tip resistance of pile and the pile top load to the reliability of pile foundation were calculated.The results indicate that when the piles penetrat multiple layers of soil,of the pile side soil will be better,that is,the bigger of the ultimate friction resistance,the greater influence to the reliability of the bearing capacity of piles and the influence of the ultimate friction resistance＇s coefficient of variation on reliability index is more obvious;the reliability index of piles decrease with the increasing of the coefficients of variation of the uncertainty factors of calculation model,the ultimate friction resistance,the ultimate tip resistance of pile and the pile top load.

关 键 词：桩基 梯度优化法 可靠度指标 不确定性 承载力 

分 类 号：TU473.1[建筑科学—结构工程]