Research On The K₀ Consolidation Characters Of Unsaturated Intact Loess And Its Applications

With the development of the west of China, more and more high grade highways are built. In this region, unsaturated loess is dealt with frequently. So it is very necessary and urgent to estimate the deformation of it in highway construction. It is the intention of this paper.With considering loess's moistening deformation and without considering loess's collapsing ones, making use of GDS(Geotechnical Digital System), Ko consolidation tests under continuous loadingare carried out on the loess(Q3) which comes from Longxi area in Gansu province. When analyzing the experimental data, the unsaturated loess is regarded as macroscopical and its four-phase system is ignored. Based on the analysis, the deforming process of the intact loess is divided into three stages because of its special structure. In the first stage, its original structure is intact on the whole. In the second, its original structure is destroying. In the third, its new structure is formed. The deformation produced in the first stage can be ignored, but it is big more in the second. So all the analyses are done according to those different stages. In this paper, the updating secant modulus is proposed. During continuous loading, the loess's structure is destroyed completely at the point of the least secant modulus and the loess's deforming process goes into the third stage after it The experiential-analytical solution of the secant modulus of different stages is deduced and the influence of water content is analyzed. In the same way, the experiential-analytical solutions of the stress-strain relationship and the coefficient of lateral pressure are deduced with considering the influence of water content in different ones.On the basis of analyzing the experimental data, the constitutive model of the relationship among stress, strain and time is established. Based on the similitude theory, the model is used to calculate the settlement of highway subgrade.Additionally, computer program is formed to make the calculation of the settlement of highway sub grade concise and convenient.