摘要
为进一步深入分析饱和黏性土的一维流变固结机制,引入Koeller定义的弹壶元件修正Merchant模型,并以此描述土骨架的黏弹性变形行为;同时引入非牛顿指数渗流模型描述流变固结中的非达西渗流,推导出一个新的饱和黏性土一维流变固结方程,并用隐式有限差分法进行数值求解。通过与有关文献中退化模型结果的对比,验证了有限差分算法的有效性。在此基础上,分析非达西渗流模型参数以及分数阶Merchant流变模型参数对流变固结过程的影响。计算结果表明:分数导数阶数和黏滞系数对地基沉降的影响比对孔压消散的影响更为明显,且分数导数阶数越小或黏滞系数越大,地基沉降需要的时间越长。同时,比起达西渗流,非牛顿指数渗流会延缓地基中的孔压消散,使得沉降发展变慢。另外,考虑流变效应时地基沉降要慢于孔压的消散。
To further investigate the rheological consolidation mechanism of saturated clay,the Koeller spring-pot element based on Caputo’s fractional derivative is introduced to replace the Newton dashpot element of the classical Merchant model.The flow model with the non-Newtonian index is employed to describe the non-Darcian flow in the process of rheological consolidation.Accordingly,a one-dimensional rheological consolidation equation is obtained,and its numerical analysis is conducted by the implicit finite difference method.In order to verify its validity,the numerical solutions by the present method for some simplified cases are compared with the results in the related literature.Then,the effects of the parameters of non-Darcian flow and fractional-order Merchant’s model on the rheological consolidation are investigated.Numerical results indicate that the fractional order and the viscosity coefficient more greatly affect the ground settlement than the dissipation of pore water pressure.The rate of ground settlement lowers as the fractional order decreases or the viscosity coefficient increases.The flow described by non-Newtonian index delays the dissipation of pore water pressure and reduces the rate of ground settlement compared with the Darcy flow.Moreover,the development of ground settlement is always slower than the dissipation of pore water pressure considering the rheological effect.
作者
刘忠玉
崔鹏陆
郑占垒
夏洋洋
张家超
LIU Zhong-yu;CUI Peng-lu;ZHENG Zhan-lei;XIA Yang-yang;ZHANG Jia-chao(School of Civil Engineering,Zhengzhou University,Zhengzhou,Henan 450001,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第6期2029-2038,共10页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.51578511)~~
关键词
饱和黏性土
流变固结
分数阶导数
非达西渗流
非牛顿指数
有限差分法
黏弹性
saturated clay
rheological consolidation
fractional derivative
non-Darcian flow
non-Newtonian index
finite difference method
visco-elasticity
