Rapid On-Site Improvement of Over-Wet Fluvioglacial Deposits Filler for Highway Subgrade Construction

The compaction of over-wet fluvioglacial deposits filler is difficult due to its high moisture content. This paper presents an easy but effective improvement method to treat over-wet fluvioglacial deposits using quicklime. Firstly, several tests are conducted to figure out the properties of the over-wet fluvioglacial deposits. Then, the relationship curves between the difference of natural-optimal moisture content and compaction degree are established. Finally, field test is carried out and the compaction degree of the subgrade soil is evaluated by sand cone method. The field test in the case study shows that the moisture content difference of filler is 10.9%, and the optimal quicklime content is 6% according to the curves. Results indicate that the average compaction degree of subgrade soil is 94.90% (>93%) and the value of CBR is much higher than required 3%, which proves that the method using quicklime works well to improve over-wet fluvioglacial deposits filler for rapid construction of highway embankment. Considering the inadequacy of stiffness of quicklime-treated filler, the rapid increase of stiffness for the upper roadbed using over-wet fluvioglacial deposits filler needs further research.