Theoretical Calculation Of Impact Roller Compaction In Loess Subgrade

In recent years, with the countries in central and western regions development, gradually speed up the development of the highway, railway industry in these areas. The problem is that the soil in the central and western regions are mostly loess, silt, sand and other poor soil, improve the quality of the roadbed has become the most important task. The fill of the Zhunchi heavy load railway subgrade is loess, in order to guarantee the engineering quality, impact roller is adopted for reinforcing roadbed rolling. In this paper, the application of the impact compaction technology on the loess subgrade is studied based on the project of the Zhunchi heavy load railway. The contents of this paper are as follows:1. For subgrade with indoor experiment analysis, get subgrade earth basic parameters; Analysis of the impact roller structure is studied, and the compaction mechanism of its two main parameters calculation, these are to provide the basis and reference for the next study.2. Through a cycle in the process of impact compaction is analyzed with mechanics, and a third of the impact load is reduced to a half sine load form, selects the pseudo-static method to calculate the stress of different filling depth of soil, get the stress distribution law.3. Through the analysis of the loess subgrade settlement, on the basis of half sine load, on the basis of FLAC3D on the description of the dynamic boundary conditions:the stress boundary calendar can be converted into velocity boundary, calculated the vertical displacement of roadbed under impact load.4. On the basis of the impact of the impact compaction characteristics, applying the theory of stress wave with double linear constitutive model, shock wave equation of a third wheel movement cycle is deduced, using the characteristic line method to calculate the soil in the process of loading and unloading stress, strain and vibration velocity of each point.5. Filling in the field with different depth of pressure test and displacement observation test, to verify the accuracy of the theoretical calculation.