Modified Duncan-Chang Model Considering Soil Structure

Recently,more and more phenomena have not been explained by the existing theories,which being noticed by engineers and researchers. As one important characteristic,structure of soil has attached more and more attention. Structure is the most important factor determining the soil's characteristics. Then it comes to be "the nucleus problem in soil mechanics in 21st century" that to establish an model about soil structure.Duncan - Chang model,an non-linear elastic model,is widely used in engineering. Because the model reflects the main rules of the deformations of soils,and parameters can be gained from triaxial tests. But there will be some differences comparing with the fact when the model used for natural clay,for the model was based on reconsolided clay,which is not the same with natural clay. The research about soil structure is not consummate,and it is difficult to make up a new mathmatic model. In this paper,basing on the results of soil tests,introducing the concept of damage,considering soil's structure,the author modify the Duncan- Chang model.Firstly,the engineering characteristics of natural clay and the research actuality,including macroscopical and microcosmic aspects. Secondly,based on the results of laboratory tests of Wenzhou clay,a kind of natural clay with most strong structure,the consolidation,the stress:strain relationship,the pore pressure and the strength of natural clay will be discussed in this paper. Then the Duncan- Chang model,which is based on the results of remolded soils,is introduced in detail,and discussed when using in practice. Based on the results mentioned above,the author modified the model,aiming at the shortage of the model. The modified model introducing damage variable takes soil's structure into account. Finally,the modified model can reflect the actual characteristics of natural clay,when using in practice.