高含水率疏浚泥沙堆场的颗粒分选特性研究

Study on grain sorting characteristics of dredged slurries in disposal area

疏浚泥吹填时的水力分选,导致堆场疏浚泥土性分区,影响堆场存储能力评估和疏浚泥脱水工艺选择。基于不平衡输沙理论,将连续方程、悬移质级配等离散求解,构建疏浚泥分选模型,分析底泥物质组成、初始含水率和吹填速率对分选的影响。结果表明:底泥物质组成对分选起主导作用,初始含水率和吹填速率对分选具有显著影响。底泥细颗粒含量高、不均匀系数大时,分选系数大,颗粒分选显著,偏离系数沿程增大,堆场疏浚泥颗粒组成与底泥差异增大。偏离系数的沿程分布特性受控于底泥物质组成。初始含水率越高,分选系数越大,偏离系数越小。吹填速率越大,分选系数和偏离系数越大。堆场疏浚泥分选规律与土性分布的相关性较好,可有效预测堆场疏浚泥土性分布。

Hydraulic sorting behaviors of dredging slurries with high water content during dredging cause uneven distribution of soil properties in the disposal area,which affects the evaluation of storage capacity of disposal area and the selection of dredging slurry dewatering process. A sorting model was considered based on the theory of non-equilibrium transportation of non-uniform suspended particles. The influence of particle composition of sediment,initial moisture content and filling rate on grain sorting are analyzed by the model. Results show that the composition of sediment plays a main role in the sorting of the dredged slurry. Initial water content and dredging rate have a significant influence on the sorting. When the content of fine particles( d<0. 075 mm) and the non-uniform coefficient are large,the sorting coefficient is large,the grain sorting is obvious,the deviation coefficient increases along the distance,and the difference between the composition of the dredged slurry particles and the river sediment increases. The larger the dredging rate is,the larger the sorting coefficient and the deviation coefficient are,and the grain sorting is obvious. The sorting law of the dredged slurry in the disposal area shows a good correlation with the distribution of soil properties.