中文摘要：

黏性非均匀沙起动和冲刷研究对于河口海岸工程的设计和安全具有重要的意义。在作者从概率论和力学角度所提出的黏性非均匀沙起动摩阻流速公式的基础上,建立起黏性非均匀沙的起动流速和冲刷率公式。在钱塘江河口河床获取2个钻孔共28个岩芯,进行起动和冲刷水槽试验。起动流速公式计算值与沙样起动试验数据符合良好,表明该公式能较好反应黏性非均匀沙的起动现象。进而根据冲刷试验资料确定了冲刷率公式的指数和冲刷常数,发现未充分固结的淤泥冲刷率与相对剩余切应力的二次方成正比,而固结已久的淤泥冲刷率与相对剩余切应力呈线性关系,冲刷常数分别为（2～3.5）×10^-5 m/s和（1～2）×10^-6 m/s,两者差一个数量级。

英文摘要：

Study of incipient motion and scour of cohesive nonuniform sediment is important for design and safety of hydraulic structures.Using the approach of probability theory and mechanics,an incipient velocity formula and a scour formula of cohesive nonuniform sediment were studied based on Sun Zhi-lin formula.The samples of the incipient motion and scour experiment were 28 drill core samples from the Qiantang River.Comparison of calculated velocity with the measured velocity indicated that the incipient velocity formula can describe the incipient motion of cohesive nonuniform sediment.On this basis,the parameters of sediment scour formula were further derived.Using the data of scour experiment,the scour rate of unconsolidated silt was in proportion to the square of relative surplus shear stress,while the scour rate of consolidated silt was in proportion to the relative surplus shear stress.The parameters of scour rate for the two cases were（2～3.5）×10^-5m/s and（1～2）×10^-6m/s,respectively.