Study On The Mechanism Of The Ice Covers’ Formation And The Impact On The Constructions Of The Water Transfer Project

To deal with the uneven distribution of the water resource and optimize theallocation of the water resource, the water transfer projects are being constructed inrecent years. When the projects are operating in winter, they inevitably face theproblems of the ice jams during freezing period. Because of the particularity andcomplexity, if we don’t apply special measures on the problems, it will decrease theefficiency of the project during the freezing period. Sometimes it will influence thesafety of the people and the property. So it’s very important to do research on the icecovers and the impact on constructions. Some scholars have done some research onthe ice covers during freezing period. But there are also lots of things to do. So thisarticle is studying on it.The article through the method of the theoretical analysis, the model test and thenumerical simulation, taking the south-to-north water transfer project as an example,study the mechanism of the formation of the ice covers and also the impact on theconstructions. This paper mainly male two parts. One part is mainly about themechanism of the formation about the ice covers. One part is about the ice mechanicalproblems (the force of the temperature expansion, the force of pulling out, the force ofcollision) during the freezing period. The main content of this article can besummarized as follows:(1) Trough the method of theoretical analysis and the model test, we study themechanism of the formation of the ice cover in the water transfer project. Firstly, wesummarize the ways and the influent factors of the formation of the ice covers. Andthen we do research on the process of the formation of the ice covers. From the test,we find out the relation between the temperature viscous sublayer and the velocity.(2) Through the method of theoretical analysis, the model test and the numericalsimulation, we study the thermal expansion pressure of the ice covers in the watertransfer project during freezing period. In the beginning, we analyze the mechanismof the thermal expansion pressure. And then we do the model test. From the study, weknow the thermal expansion pressure grows in a linear trend with the thickness of theice. Through the finite element simulation of the full scale model, we know themaximum thermal pressure is102.21kN/m, when we take the thermal expansionpressure as horizontal load. It’s very dangerous to the aqueduct structures, so we musttake some measures to prevent it. (3) Through the method of theoretical analysis and the model test, we study thepull force. From the study, we know the key point in the process of damaging due tothe pull force is the characteristics of the ice itself. The value of the pull force isdeveloping in a quadratic relationship with the strength of the ice itself. From themodel test, we can get the maximum value of the pull force, which is121.10N.According the ratio1:10and the similarity relation with the geometric prototype, wecan get the maximum pull force acting on the floodgate pillar is121.10KN.(4) Through the method of theoretical analysis and the model test, we doresearch on the impact force of the pack ice and the crushing force of an ice sheet.Firstly we study the mechanism of the forces. And then we do the model test. Fromthe study we know the impact force of the pack ice is larger than the crushing force ofan ice sheet. When the speed of the pier ice is0.79m/s and the thickness of the ice is0.41m, the ice force is2349.3kN, which is maximal. Through the analysis, we can seethe impact force of the pack ice and the crushing force of an ice sheet is very large,that should not be neglected.