Abstract: The compaction column is a common soil improvement method for the collapsible loess soils and the verification of the soil improvement effect of the compaction columns can improve the understanding of this method. A trail site was selected before the soil improvement project. Laboratory tests, field plate loading tests and the geophysical surface wave methods were used to examine the effect of the trail compaction columns. The soil physical and mechanical properties of before and after the improvement were compared. The results indicate that the collapsibility of the loess soils within the foundation influence zone can be eliminated and the bearing capacity of the composite ground is also satisfactory.

Key words: Compaction Columns, Collapsible Loess Soils, Experiments, Soil Improvements