Deformation Characteristics Of Unsaturated Loess,

Highway subgrade is the main body of the highway structures. The study of the subgrade settlement is excited attention from the beginning of express highway construction.However there is still no one reliable and simple method to calculate the settlement. This will influence the highway construction and the development of the theory. As a result, the paper will discuss the relationship among stress, strain and time of unsaturated remolding loess and rheological characteristic of loess. A simple and practical method calculating the settlement process of fill will be put forward.According to the consolidation tests indoors, this paper analyzes the secant modulus of the unsaturated remolding loess, the curve of stress and strain can be described with hyperbolic curve; the definition of secant strain rate is put forth; the deformation behaviors of soil are analyzed in terms of rheology; contrasting the resultwith the test data, the paper approves that the hyperbolic curve and the ln(ε/t) ~ Int curve can describe the development process of strain with time; the ε ~ In t curve and the ln(ε /t) ~ e curve are linear under low stress and become apparentnon-linear when the stress level is high; through the analysis of the their parameters and theoretical derivation, three computational modelings are established: hyperbolamathematic model, Kelvin-hyperbola mathematic model and ln(ε /t)~Intmodel(logistic model).At last the settlement process of the road embankment of Lan-Hai express highway is calculated with the computational modelings given in the paper. Contrasted with the practical settlement process, the computational modelings are feasible to calculate the settlement process of soil body.