Self-weight consolidation and compaction of sediment in the Yellow River Delta,China

Extensive studies of land subsidence in the Yellow River Delta (YRD) have identified sediment consolidation and compaction as important contributors to geologic processes. Although previous studies were informed by detailed knowledge of subsurface getechnical properties and depositional history, geotechnical data that are sufficient for detailed modeling are still unavailable for much of the delta. To overcome this limitation, we use a modified Monte Carlo method to model the incremental sedimentation and compaction in the delta and identify the stratigraphic characteristics of all abandoned lobes in the delta on a short-term scale of decades. A Digital Elevation Model (DEM) of the thickness of the delta plain is generated based on a contour map of the delta using Geographic Information Systems technology. Combining our simulation results and the DEM creates an overall view of the delta’s temporal and spatial land subsidence characteristics. Most data from the 152 boreholes show properties of soft soil, which is saturated and compressible. Our data confirm that the most rapidly compacting strata contain 100% soft soil. Research on settlement from soft soil compaction is particularly important because of the widespread distribution of soft soil in the YRD.     

Effect of self-weight consolidation on a hydro-sedimentological model for the Río de la Plata estuary

The effect of the consolidation process on the morphodynamics and fine sediment dynamics of the Río de la Plata estuary is explored through a circulation-wave-sediment transport model. The consolidation model is calibrated based on settling column experimental data. Different simulations are done in order to initialize the mud layer distribution and to investigate the impact of different erosion parameter assumptions on the modeled sediment dynamics. Finally a two-year simulation is done with and without the consolidation process and realistic hydrodynamic forcings. Considering the consolidation process, the model correctly reproduces measured vertical density profiles in the Montevideo Bay access channel. The simulated suspended sediment dynamics behavior in Montevideo Bay with the consolidation process provides a more realistic deposition pattern in regard to the dredging activities.     

土体自重固结压缩对地面沉降影响研究

以南通市为例,建立了土体自重固结压缩、地下水开采与地面沉降三维全耦合模型.在对模型进行识别、验证的基础上,模拟预测了南通市在地下水停止开采,仅在土体自重固结压缩影响下,自2010年12月31日-2025年12月31日各含水层组地下水流场变化和地面沉降的发展趋势.结果表明,在此期间,南通市由土体自重固结压缩引起的最大地面沉降量为2.42 mm,最大地面沉降速率为0.16 mm/a,土体白重固结压缩对南通市地面沉降的影响极为有限.