ESTIMATION OF SEDIMENT COMPACTION AND ITS CONTRIBUTION TO LAND SUBSIDENCE IN THE YELLOW RIVER DELTA

Using the stratified summation method based on soil mechanics with 152 boreholes obtained from the Project on Comprehensive Engineering Geological and Hydrogeological Survey (1987), we estimate the land subsidence in the Yellow River Delta caused by sediment load. Results show that almost the whole Yellow River Delta is influenced by land subsidence caused by sediment load. The subsidence changes from 157mm to 1 398mm and the average is 669 mm. It shows an increasing trend from the southwest to the northeast. Our estimates also suggest that soft soil layer is the major contributor to the land subsidence which accounts for 65% of the total compaction subsidence. The results is reasonable after comparing with the benchmarks obtained from near 10 boreholes. Furthermore, the contribution of sediment compaction to land subsidence is computed. The results range from 2.1% to 15.0%, and the average is 4.0%. Sediment compaction is expected to retain for a long time in the Yellow River Delta area.