Local Scour And Protection Of Bridge Pier Under Ice Sheet

The local scour of bridge pier under ice sheet is a three-dimensional problemwith multitude of factors. There is currently no scour protection methods that havesufficient theoretical basis and fully effective.Theoretical analysis and experimentalresearch of local scour and protection under ice sheet of bridge pier is of greatsignificance for the construction of bridges at high latitudes of our country.In this paper, the turbulent characteristics of the flow under ice sheet aretheoretical analyzed and experimental researched, the local scour of bridge pierunder ice sheet is experimental studied, the protective effect of retainer isexperimental studied and numerical simulated. The main results are as follows:(1) In the case of flow conditions are basically the same, vertical turbulenceintensity of ice flow is bigger than that of free flow; and with ice roughness increases,vertical ice flow turbulence intensity increases.(2)There is a new monitoring device using light refraction in this paper is used tomonitor local pier scour. In contrast to traditional measurement methods, theadvantages of the device are: simple structure and easy to operate; economical andpractical; can be used with water; monitoring equipment is outside the body of water,has not affects for erosion process.(3)The presence of ice has facilitating role on the development of local scour,and with the ice roughness increases this role increases.(4) Scour pit slope is not static, it is fluctuate around a mean value.(5)Retainer has inhibit role to the development of the scour hole, and When theRetainer is closed to the bed it has a lag role to the development of the scourhole.The bigger the retainer is,the greater of these two roles are. When the Retainerdiameter equals to three times of the diameter of the pier, the local scour of the piercan not be observed within3hours.(6)Retainer has inhibited roles to the undercurrent in front of the pier and thewhirlpool behind the pier, with the ice diameter of the Retainer increases these roles increase.