Research Of Ice-Cover Breakup Mechanism Based On Mechanics Analysis

Ice is a natural phenomenon, the evolution of the river ice include ice period、forbidden period and thawing period, every period may lead to different ice disasters,especially in thawing period, the ice disaster occurred most frequently. The rapid changesof hydrodynamic conditions in cold region rivers during spring season often lead tomechanical ice-cover breakup (commonly known as "Wu Kai He" in China). In thisperiod, ice sheet rupture during ice-cover breakup period mainly because the temperaturemutation or upstream watershed concentrated rainfall which lead to river discharge andwater level rise rapidly. This phenomenon will lead to the formation of ice dams andeven natural disasters which hazard to people’s lives and property, so the analysis of riverice is very important for water resources construction in high latitude areas. Based onplastoelasticity, model of ice-cover breakup was established by theoretical analysis andice sheet cracks the critical deflection and break-up water level was studied under theelastic-plastic state, thus the impact of water level change on the break-up date wasobtained. Appling the measured data of the Yellow River to the calculate model can getthe usefulness of the discriminant function, thus the size of the ice sheet under the flowof critical on the lifting force was got during this period.