Study On The Influence Of The Rheology In Subgrade Settlement After Construction Under The Load

With the great development of the high speed railway in China, the railway transportation changes upside down, which makes us more convenient. In order to ensure the comfort, amenity and safety, the track structure used to be ballastless. This structure require a strict after-construction settlement which depends on a high-precision calculation during the design process. Settlement of composite foundation is always an important engineering problem and the soft soil area distributes widely in China, rheological properties of soft soil has a large influence on the after-construction settlement. If we ignore the creep of soft soil, the calculated settlement will be too small or too conservative.In this paper, the author base on the Wuhan-Guangzhou high speed railway measured data of settlement, and use the finite element software ABAQUS to establish the corresponding model. The static load and dynamic load is applied to the model respectively. And compare to the model which ignore the creep of soft soil, the author got the the performance of rheological behavior of soft soil under the different conditions. Specifically, the author has done the following work:1. Through reading a great deal of literature and doing research on the existing academic achievements, the method of settlement curve fitting are summarized. Based on the actual settlement measurement data of Wuhan-Guangzhou high speed railway, the author calculated the final settlement by using the method of curve fitting and put forward the best and the most suitable method in the situation of the soil.2. Using the finite element software ABAQUS to build the two subgrade models, one of which considered the creep of soft soil and the other is not. Both of them are based on the actual subgrade design, choosing the corresponding constitutive models. Soil parameters, boundary conditions and strengthening methods are consistent with the actual engineering.3. Under the static load conditions, the simulation result is compared to the curve fitting result and the actual settlement measurement data, so as to verify the correctness of the model. On the other hand, the analysis are made from the final settlement and the pore pressure between the two models, which come to conclusion about the influence of settlement under the rheological soil factors. At last, in the model of creep, the author has the sensitivity analysis about the rheological parameters A,n,m, to summarize the numerical size effects on the rheology of soil settlement.4. In the study of the literatures, using the excitation formula to simulate the dynamic load under the different speed. And improve the original model to load the dynamic load. Compare the model considered creep to the model not, find out the influence of the rheological factors under the dynamic load. At the same time, the dynamic response at different speed of load in the rheological model is analyzed, in order to find out the effect of soft soil rheology.