中文摘要：

将基于固结试验建立的Koppejan蠕变模型应力一应变一时间关系改进为增量形式，并泛化到三维应力窄问，建立了改进的Koppejan蠕变模型。基于ABAQUS软件对改进模型进行二次开发，采用上海软黏土的长期周结试验结果对模型进行验证，结果表明，Koppejan模型能较好地描述上海软黏土的蠕变特性，且改进Koppejan模型的计算精度比经典Koppejan模型高，两种模型应用于淤泥质粉质黏土的计算效果均比粉质黏土好。将改进Koppejan蠕变本构模型应用于某高速铁路桥梁桩基长期变形的三维有限元分析，与现场实测沉降的对比表明，改进Koppejan模型能较好地应用于实际工程的长期变形计算，且计算效果较好。

英文摘要：

The stress-strain-time relationship of the Koppejan creep model based on consolidation tests is improved to theincremental form, which is generalized to 3D stress space, and then the improved Koppejan creep model for soft soil is established inthis work by the incremental form. Based on the ABAQUS software, an UMAT is developed by the improved Koppejan model. Usinglong-term consolidation tests of Shanghai soft clay to validate the model, the results show that the Koppejan model describes thecreep property of Shanghai soft clay very well; the computational accuracy of the improved Koppejan model is better than that of theclassical Koppejan model, and the two models work better for mucky clay than silty clay. Using the improved Koppejan creepconstitutive model to the three-dimensionaI FEM of a high-speed railway bridge pile foundation long-term deformation, andcomparing with the measured settlement, the results indicate that the improved Koppejan can be well used for computing long-termdeformation of actual projects.