Role of a constitutive model in the stability problem of clay

在本研究项目中，我们推导了从各种室内和现场粘土试验中获得的强度参数。其基本思想是建立增量型弹粘塑性本构模型。特别是对等体积剪力箱试验和现场叶片试验所获得的强度参数进行了分析，这两种试验费用相对较低，但由于其理论基础不成熟，在工程实践中并未得到广泛应用。除了强度参数的纯理论推导外，我们还开发了计算机程序来模拟与粘土破坏有关的三维土/水耦合问题。这个有限元程序需要一台超级计算机来解决问题。利用基于弹粘塑性本构模型的三维土/水耦合有限元程序，成功地模拟了定容剪切箱试验和现场叶片试验。这一结果与从全国各地采集的各种粘土的试验结果吻合较好。

In this research project we have derived the strength parameters to be obtained from various kind of laboratory and field tests on clay. The basic idea is in the development of an elastic-viscoplastic constitutive model of incremental type. Especially we have paid attention in analysing the strength parameters to be obtained from the constant-volume-shear-boxtests and the field vane tests both of which are relatively inexpensive and yet are not widely used the in engineering practice for a reason that their theoretical backgrounds are not well-established. In addition to the purely theretical derivation of the strength parameters, we have developed computer programs to simulate the 3-dimensional soil/water coupling problems associated with the failure of clay. This FEM program requires a super-computer to solve the problems. By using the FEM program developed for 3-D soil/water coupling problems based on an elasto-viscoplastic constitutive model, constant-volume-shear-box tests and field vane tests are successfully simulated. The results are in good accordance with the tests on various kind of clays collected from over this country.