Settlement And Stability Analysis Of Railway Rock-Filled Embankment

With rapid development of China railway construction, crushed stone is used more and more in roadbed construction, especially in mountainous areas of southwest China. Currently, there is little domestic research on rock-filled embankment. At the same time, methods of specific construction and the control of settlement are not perfect. The standard of quality inspection has been not set up yet. Builders often refer to the highway and water conservancy rock-filled dam project. Settlement and stability are absolutly important to rock-filled embankment. There are many factors which will affect the stability and settlement of rocked-filled embankment. It is necessary to research each specific construction conditions influencing on embankment. Similarly, It will play an important roles to controlling the post-construction settlement of rocked-filled embankment and the train safe operation.The thesis is mainly based on the key railway technologies research subject of Guiyang to Guangzhou hard rock-filled embankment. According to the scene of the test section construction, we plan to carry out the research including the selection criteria of rockfill, construction procedures and the quailty control. Moreover, we will compare the actual measured value with the results of the finite element method analysis as well as propose the specific construction procedures to control the settlement of the rock-filled embankment and which measures should be taken to. Meanwhile, with the aid of the finite element analysis software, we established the2D and3D calculation model of the rock-filled embankment and research some factors and conditions which wil influence the deformation and the scope of mechanical properties. Under the effects of train load, we have analysised the time history of the displacement and stress and also put forward some advice for the design and construction. The main results of the paper are as follows:1. The choice of rock fill and each step of embankment construction have been strictly controlled in the whole course of construction to reduce the post-construction settlement and meet the safety stability.2. The two-dimensional model was established by the numerical analysis MIDAS/GTS. Under the train load, rock-filled embankments which are consist of five different particle size of rockfill was simulated to analysis the stable safety factor, all directions of displacement and maximum stress and strain. Compare the smaller particle size with the bigger, it can be concluded that embankment is relatively in a more safety state under the same load, boundary conditions and construction conditions. 3. The safety stability factor of embankment increase modestly with the decrease of the embankment slope. This change is also suitable for the unit stress and strain. It is indispensable to foundation treatment when the strength of foundation does not meet the basic bearing capacity which is required in the norm. The underground water level at different height almostly has no effect on rock-filled embankment4. Through the construction stage analysis of rock-filled embankment and comparing the measured values with calculated values of finite element, we can get the result that the two values coincide. Engineering practice shows that the finite element simulation is feasible.5. During the period of the train operation, the three dimensional finite element simulation which was under the train dynamic load mainly computed the force, settlement and stability of rock-filled embankments which were composed by the five rockfill of different particles size. The purpose is to analysis the eigenvalue and the time history of stress and displacement. In general, according to the dynamic analysis of rock-filled embankment, whether the stress and deformation of nodes or the whole embankment both can satisfy the requirement during the train operation. The calculation results indicate that the rock-filled embankment is in a safe and stable state.