How to analyze whether sand produces quicksand under the action of hydrodynamic force

I know that the formation of quicksand is varied. The main reason is the sand layer formed by alluvial geological changes of rivers. In the case of water flow, the whole sand layer flows, thus forming a quicksand layer. There are also quicksand beds along the Yangtze River, along the Huaihe River and in Dangshan and Xiaoxian counties of our province. Quicksand, as its name implies, is quicksand, mainly because sand meets water underground. When the water pressure changes, the water flows, so the sand flows with it. In general, the pressure of groundwater is constant, but once the water pressure changes, the whole sand layer will also change, so it is of great significance to deal with quicksand for foundation construction. Correctly handling the negative influence of quicksand layer in foundation construction can not only effectively control the project cost, but also improve the construction technology level.

Liquefaction of sand refers to the mechanical process that saturated fine sand or light loam loses its strength instantly under the action of earthquake force and changes from solid to liquid. The liquefaction of sand is mainly due to the increase of pore water pressure on sand, the decrease of shear strength or shear stiffness, and tends to disappear under static or dynamic action.

With the devastating earthquake, the damage caused by sand liquefaction is very serious. Water-jet sand blasting makes the pore water and sand particles in the underground sand layer move to the surface, which makes the foundation invalid, and at the same time, the solid and liquid substances in the underground soil layer are missing, resulting in different degrees of settlement. The buildings on the ground tilt, crack, topple and sink, the road subgrade slips, and the pavement runs vertically on the river bank, which is manifested by the river bank sliding and the bridge falling off. In addition, a large number of sand grains in the soil layer will emerge together with the loss of powerful confined water, and accumulation in farmland will cause large-scale damage to crops.