摘要
对利用有限元计算分析张紧式吸力锚承载力的方法进行了研究,结果表明:锚土之间接触特性的描述取决于锚的破坏模式;当锚为竖向破坏时,采用临界剪应力摩擦模型描述锚土间接触是恰当的;当锚为水平破坏时,采用库伦摩擦模型描述锚土间接触是恰当的。计算中若采用基于Mises屈服准则的理想弹塑性本构关系描述软土的不排水应力应变特性,且按位移标准确定极限承载力,则弹性模量的取值对确定软土中吸力锚承载力有影响且取决于锚的破坏模式;当锚发生竖向破坏时,弹性模量按约150倍的不排水强度取值是恰当的;当锚发生水平破坏时,弹性模量按约75倍的不排水强度取值是恰当的。探讨了依据软粘土循环强度利用拟静力弹塑性有限元计算,估算平均荷载与循环荷载共同作用下吸力锚平均位移变化趋势的可行性,计算与模型试验结果比较说明,计算得出的拟静力荷载位移曲线能够对锚实际平均位移的变化趋势给出一个恰当的估计。
The method to analyze the bearing capacity of suction anchor is studied by finite element calculations.The interaction between anchor and soil should be determined by the failure mode of anchor.When the failure mode of anchor is vertical pullout,it is proper to use a critical shear stress friction model to describe the interaction between anchor and soil.When the failure mode of anchor is lateral failure,it is proper to use the Coulomb friction model to describe the interaction between anchor and soil.The value of elastic modulus has effects on the ultimate bearing capacity and depends on the failure modes of anchor if the undrained stress-strain relationship of soft clay is described by the perfect elastic-plastic model obeying Mises failure criterion and the ultimate bearing capacity is determined based on the displacement standard.The elastic modulus is determined using 150 times of the undrained shear strength of soil when the failure mode of anchor is vertical pullout.The elastic modulus is determined using 75 times of the undrained shear strength of soil when the failure mode of anchor is lateral failure.The feasibility estimating average displacement of anchors is also investigated by pseudo-static elasto-plastic finite element calculations using the cyclic shear strength of soft clay under combined average and cyclic loads.The comparison between the calculation results and the results of model tests shows that variations of average displacement can be estimated.
出处
《海洋工程》
CSCD
北大核心
2013年第4期10-20,共11页
The Ocean Engineering
基金
国家自然科学基金资助项目(51179120)
关键词
粘土
吸力锚
破坏模式
循环强度
承载力
soft clay
suction anchors
failure modes of anchor
cyclic shear strength
bearing capacity
