Study Of Rheological Characteristics And Constitutive Model Of Peaty Soil In Kunming Basin

It is known that the formation of soil is related with its surroundings. Kunming area is in Dianchi lake watershed, which has many rivers and lakes, and lots of aquatic and hygrophytes plants. After many years of paludification and sedimentation, the residue of these plants form peaty soil that is full of organic matter.The rheology behavior is one of the most remarkable characteristic for weak soil. The peaty soil in Kunming basin, a special weal soil, shows rheology behavior, which has reflected in many existed program. But the research on the rheology behavior of peaty soil in Kunming basin is still in initial stage and the soil is treated as elasticity or elastoplasticity, which is not agree on the fact. With the development of Kunming economy and the increase of constructing and proposed program, the land has been increasingly scarce. Therefore, many programs have to be constructed on peaty soil. In order to decrease building risk caused by its rheology behavior, it is necessary to give more attentions on the research of rheology behavior. For this reason, the rheology behavior of peaty soil is studied in this paper and the main content and the conclusions are listed as the following:(1)The subject of this research is peaty soil in Kunming basin, and indoor constant load loading creep test and constant load unloading creep test are made on it. The simultaneous part loading and step loading are adopted by analyzing the pros and cons of creep test loading styles. The loading and the unloading creep curves are obtained by analyzing the test data and the results show that the peaty soil in Kunming basin has the rheology behavior noticeably。(2)Based on creep curves, the stress-strain tautochrone curves are analyzed, which divides the creep deformation of peaty soil in Kunming into three different styles, i.e. linear visco-elastic deformation, linear visco-plastic deformation and nonlinear visco-plastic deformation. The model theory is used to model the linear deformation and the empirical model of power function is adopted to model nonlinear deformation. Then the parameters in the model are solved.By comparing the results in the tests and the results of the model, it's shown that the model has good effectiveness.