考虑时间效应的粒状材料的UH模型

Time-dependent unified hardening model for granular materials

近年来,山区支线机场建设日益增多。机场高填方工程往往填方量较大,就地取材,填料含有土料、砂料、堆石料等不同岩土材料。准确预测填料的工后沉降变形影响到机场的安全性和正常运营。相对于黏土,粒状材料特性往往更复杂,可能会出现颗粒破碎等现象。现有的黏弹塑性本构模型大部分只适用于黏土,不能直接用于计算粒状材料流变变形。本文提出一个能够统一描述黏土和粒状材料应力–应变–时间特性的考虑时间效应的粒状材料的UH模型。并且给出了将该模型利用ABAQUS二次开发接口,编写用户子程序,进行有限元实现的过程。最后,利用模型对黏土剪切蠕变试验及砂土三轴不排水试验进行预测,并与试验结果对比,验证了模型的正确性,说明模型能够较好地描述黏土和粒状材料的应力–应变–时间关系。

In recent years,the construction of regional airports in mountainous areas is increasing.The high-fill engineering projects have large fill volume and use local materials,which contain soil,sand,rockfill materials and other geotechnical materials.Accurate prediction of the post-construction settlements of hill-fill foundations affects the safety and normal running of the airports.Compared with those of clay,the properties of granular materials are often more complex,such as particle crushing.Most of the existing viscoelastic-plastic constitutive models are only for the clay,and cannot be directly used to calculate the rheological deformation of granular materials.A time-dependent unified hardening model suitable for granular material is proposed,which can describe the stress-strain-time characteristics of clay and granular materials in a unified way.The process to develop the new constitutive model in ABAQUS by using the user subroutine is given and implemented.Finally,the new model is validated through test results,including triaxial drained creep tests on clays and triaxial undrained tests on sand.It is shown that the model can well describe the stress-strain-time relationships of clay and granular materials.