Research On Effective Influence Depth Of Zhun Chi Heavy Haul Railway’s Loess Subgrade Under Impact Compaction

With the development of society and economy, more attention is paid to the heavy haul railway; subgrade’s quality improvement is the top priority of the heavy haul railway’s development. With the rise of the impact roller, using impact roller to reinforce the subgrade is widely paid attention to. Zhunchi railway is class-I heavy haul railway, this paper is based on the subject of "Study on mechanism and quality controlling about impact compaction of loess subgrade", studying the effective influence depth of the Zhunchi heavy haul railway’s loess subgrade under impact compaction.This paper’s main research contents are as follows:1. The impact load is simplified to triangle load, the vertical displacement of the loess subgrade under impact is calculated with improved Scott formula, and thus getting that the effective influence depth is related to impact times. Using the additional stress to calculate, it gets the stress of loess subgrade under impact process, after analyzing the calculation results, it is found that the effective influence depth at about 2 m.2. Simulated impact compacted loess roadbed using the finite element software ABAQUS, through the analysis of simulating stress and displacement results, it obtains that the effective influence depth was 1.8 m.3. In the field, through the soil pressure sensors embedding test, displacement monitoring test and drill core sampling test, the loess subgrade’s pressure value, displacement and compaction of different depth after impact compaction are obtained. After the analysis, it is found that the effective influence depth was 2 meters.After comprehensive analysis, in view of the ZCZQ-4 section’s loess subgrade construction of Zhunchi heavy haul railway’, the effective influence depth of impact compaction is 2m.