The Analysis Of Subgrade Settlement After Construction Considering Rheology In Soft Soil Area

In order to meet the growing transportation demand of passengers and freight, China has raised a wave of high-speed railway construction. High-speed railways adopt the technology of ballastless track, and the ballastless track high-speed railway has a strict limit of settlement. However, the current criterion still lack of study for the long-term effects of soil consolidation and rheology on the composite foundation .These behavior of the soft soil have obvious effects on the post-construction settlemen of ballastless track high-speed railways.In China, there are large areas of soft soils, and soft soil have remarkable property of rheology. It will be of great significance of the studying on the effects of the rheology to settlement after construction.In this paper, based on the creep experiment, a railway settlement model considering both consolidation and rheology is established in the finite element software of ABAQUS. The embankment settlement is calculated using this model and making a comparison with the value of the model only considering the soil consolidation. After that, The effect of rheology of soil on post-construction settlement is analyzed.The main work of the thesis are as follows:1. The laboratory tests of rheological characteristic of soft clay are performed on the basis of papers abroad and in. Systematic test dates about strain-time and srtain-stress behavior of the soft soil under different stress levels are achieved.Rheology characteristic of soft soil in Tianjin-Binhai district are analyzed according to test results;2. Based on the test results and time-hardening law, a rheology constitutive model is established, and the parameters in the model is determined according to the tests data;3. A railway settlement model considering both consolidation and rheology of soft soil is established in the finite element software of ABAQUS. The embankment settlement is calculated using this model and making a comparison with the results calculated using the model only considering the soil consolidation. After that, the effect of rheology of soft soil on post-construction settlement is analyzed;4. Parameters sensitivity analysis is performed based on the basic model. The effects of soil parameters including the cohesion c, the soil friction angleφ, and the creep parameters A, m, and n on post-construction settlemen is studied.