Study On The Filling Heave Classification Of The Railway Subgrade

The frost heave is one of the railway subgrade unique diseases in cold area; therefore, when it is constructed in the cold area, the roadbed should not only conform to standard in warm zone, but also consider the impact of water in the frozen soils and the heave sensitivity of the filling. At present, the measure of preventing the embankment disease is to prevent the surface water and groundwater submerging into roadbed, as well as use the heave insensitive filling. However, when the applicability is considered, there is some problem which should be solved in design. For example: How to define the heave sensitivity? What is the factor affecting the heave? How to divide the grade of the heave? And so on. There is more important that how to solve the problem of the roadbed by the way of changing filling.Based on these questions, the paper has done the work as follows:Firstly, through the domestic and foreign data analyzing, the factors influencing heave of the roadbed have been founded, including the soil, the water, the temperature, the saline matter, the external applied load and so on. The soil mainly refers to the mineral ingredient, the mechanical component (soil fraction); The water mainly refers to moisture content and the change of the moisture content; The temperature mainly refers to the change of the temperature and the temporal and spatial variation; The salt mainly refers to the ingredient of the soluble salt and the content; The external applied load refers to the load dimension, the speed and the way that applied to the subgrade and so on;Secondly, through the laboratory experiments, the paper has analyzed the classification way of the heave sensitivity, the heave graduation way which domestic and foreign often adopts about the soil heave classification, proposed the index mark that the filling heave classification and graduation of the roadbed, and the scheme of the filling heave classification;The index includes the soil and moisture content: the soil refers to the content of the silty and clayey (<0.075mm) for the coarse- grained soil heave and it refers to the plasticity index and liquid limit.The index mark which has been adopted by the filling classification plan is the heave high, it was divided four classes, they are I level, II level, III level, IV level, the...