适于基坑开挖分析的一个改进双屈服面模型

Modified Two Yield Surface Constitutive Model for Finite Element Analysis of Deep Excavation

针对基坑开挖应力路径的复杂性及土体剪切变形显著的特点 ,将椭圆抛物线双屈服面模型应用于开挖有限元分析 .该模型可避免常规模型 (如邓肯模型、修正剑桥模型等 )的理论局限 ,又可避免一些特殊模型要做非常规试验才能确定参数的缺点 .研究表明 ,按原有参数确定方法确定的KG 偏大 ,致使计算的支护桩体位移和地面沉降偏小 ,弯矩偏大 ,文中对其作了改进 .

Considering the complicated stress pathes and the apparent shear deformation of soil during excavation,a modified two yield surface constitutive model is applied to finite element analysis of deep excavation.The model can avoid some defects of other models.However the parameter“ K G ”is too large if it is determined by the original method;for this reason,a modified method is proposed.