The fiber inclusion could be easily distributed in the specimens and bear the pulling stress inside when the fiber content is relatively low. But it would be hard to blend the fiber or strips discretely if the fiber contents were excessive. Thus, excessive fiber inclusion might tangle together in some parts of the specimens so
that the cementation and fiber bonds there were obstructed. It can be concluded that both two types of improved soil reached their peak strength at the fiber content of 0.5% and that, considering the fiber content of 0.5% as a threshold, the strength had an overall trend to decrease with the increase of fiber content beyond the
threshold.