CHANGES OF LOESS ENGINEERING PROPERTIES DURING FLOWING PROCESS FROM YELLOW RIVER TO SEA

Millions of years ago, seemingly boundless sand storms covered northwestern China, which formed loess deposits several hundred meters deep. Some loess was transported thousands of kilometers away through the river system to the coastal area of the Bohai Sea, which generated the Modern Yellow River Delta. The engineering properties of loess changed from Yellow river to the sea. The physical mechanical properties, gradation composition, microstructure and dynamics properties of loess are obtained based on the achievements along the Yellow River in the past 30 years and researches on estuary sediment in the latest 10 years. Analysis of these data shows that the unit weight and water content increased in the process of transported into sea, while the plastic index decreased. The major contents of loess are silt, with little sand and clay. The clay content increased while sand content decreased. Consequently, the void was filled better, and the compressibility of loess reduced. The shear resistance shows big differences at different areas. The earthquake resistance and liquefaction resistance were increased. This paper is of great significance to better understanding the mechanism and prevention of the loess geological disasters.