Experimental Study on the Over-Consolidation Stress History of Subgrade Compacted Clay

To study the over-consolidation stress history of clay in a high-filled embankment during hierarchical compaction, indoor compaction and one-dimensional consolidation tests are performed on roadbed backfill clay. Two homemade compaction devices are used to drill into standard heavy compacted clay to prepare compacted clay samples and subsequently investigate the influence of compaction work, compaction impulse, water content, and compaction degree on over-consolidation stress history. Results provide an experimental basis to determine the parameters of an over-consolidated constitutive model. Experimental results show that compacted clays with the same compaction degree and water content can differ in stress history, and that this stress history increases as the compaction impulse per unit area builds up. Under the conditions of the same compaction work and over-consolidated formation, the compacted clay achieves the maximum compaction degree and stress history if water content is at the optimal level. If the water content deviates from the optimal level, the stress history of the compacted clay decreases, and it is more significantly affected by the compaction degree with increased water content.