结构性软土弹塑性损伤模型及其应用

Elasto-plastic damage constitutive model and its application to structural soft soil

为了考虑结构性对软土工程特性的影响,引入结构损伤变量,在岩土损伤力学理论和经典的修正剑桥模型基础上建立扩展的弹塑性损伤模型,通过固结压缩试验和三轴剪切试验确定模型参数.在通用有限元软件ABAQUS平台上开发所建立的弹塑性损伤模型UMAT子程序.将所建立弹塑性损伤模型应用到室内固结压缩试验和现场堆载预压试验的数值模拟中,并与修正剑桥模型所得结果进行对比.结果表明,当荷载较低时,弹塑性损伤模型计算所得沉降小于修正剑桥模型的结果;当荷载大于结构屈服压力时,弹塑性损伤模型计算所得沉降大于修正剑桥模型的结果,即弹塑性损伤模型能够反映软土结构性的特点.

Structural damage variable was introduced to consider the effect of structural property on the engineering characteristic of soft soil.An extended elasto-plastic damage model was established on the basis of soil damage mechanics theory and the classic modified Cambridge model.The model parameters were determined through consolidation test and triaxial test.The UMAT subroutine of the elasto-plastic damage model was developed on the platform of ABAQUS.Finally,the elasto-plastic damage model was applied in the numerical simulation of laboratory consolidation test and in-situ preloading test,and the results were compared with those of the modified Cambridge model.The results showed that the settlement computed by the elasto-plastic damage model is less than that of the modified Cambridge model when the load is low,but it is opposite when the load exceeds the structured yield stress,which indicates that the elasto-plastic damage model can reflect the structural property of soft soil.