Study On Frost Resistance Numerical Simulation Of The U-shaped Concrete Lining And Transverse Joint

This paper contrapose the frost damage problem of the prefabricated u-shaped concrete channel in seasonal frozen soil irrigation area,Based on with three places in five channels in northern Yinchuan irrigation area as research area,meanwhile the wild frost heaving observation base of prefabricated u-shaped concrete channel in Wencui campus of Ningxia university as research area,Using the method of combining survey research,field observation and computer numerical simulation,provideing a theoretical basis for popularizing anti-seepage and frost resistant technology of fabricated U concrete channel.The main results of this study are as follows:(1)Come to a conclusion through field experiment of frost-heaving data collection of u-shaped concrete channel:low temperature period of channel soil and high value area of frost heave amount appear in late December,2015 and late January of the following year,the least value of temperature and the crest value of the frost heave amount tend to appear in this range.The temperature of channel soil is close to frost heave force and frost heave amount.With lower temperature,frost heave force,frost heave amount has a rising trend.The influence of frost-heaving among sunny slope straight line segment,sunny slope curve segment,shady slop straight line segment and shady slope curve segment are significantly different and the frost heave amount of channel soil reaches crest value in shade slope curve segment.(2)Come to a conclusion through observation research of the U-shaped concrete lining channel in the northern Yinchuan irrigation area.In the geometric parameters setting of finite element model,the conclusion is:the width of the lining plate be set to 40 cm,angle be set at 22°,thickness be set to 6 cm,the width of the joints is set in 3-18cm between the scope of the study,the research range of concrete strength is C15-C30,frost heave cracking position is generally on the junction of straight line segment and curve segment with about 2mm width,and the frost heaving damage is more serious in transverse joints than in lining slab and more serious in shade slope lining slab than sunny slope lining slab.(3)Come to a conclusion through the frost heave simulation analysis of the U-shaped concrete lining channel:increased strength of concrete in transverse joints is favorable for channel resistance to frost heave,especially in straightsections,but in arc sectionsthe performance is more obvious.Compared by the maximum amount of frost heave reduction,selection of strength grade C25 concrete as a transverse joint material to consider more appropriate.In the process of increasing the width of the transverse joints,the frost heave displacement of the transverse joint is decreasing.When the width of the transverse joint is 15cm,the reduction of maximum frost heave displacement in shady slope,taking into account the site construction work,therefore,it can be used as a reference value of the width of the transverse joint in the channel design.The cracks of U-shaped channel is mainly due to the connection between the straight sction and the arc section.In case of frost heaving damage,the shady channel is more serious than sunny one.The characteristic of the simulated cracks coincide with the actual one.