Over consolidation ratio decreases with depth why give reasons?

The over-consolidation ratio (OCR) decreases with depth primarily due to the increasing vertical stress from overlying soil layers, which leads to greater consolidation of the soil. As depth increases, the historical maximum pressure that the soil has experienced—its preconsolidation pressure—also increases, resulting in a lower OCR. Additionally, deeper soils are often subjected to more geological processes, such as compaction and settlement, which can further reduce their over-consolidation status. Consequently, deeper soils tend to behave more like normally consolidated soils, exhibiting lower OCR values.