Application Research Of Lightweight Concrete In Railway Embankment Widening Project

With the development of China's railway construction industry,more and more railway stations are merged,lines are connected in parallel,and they are crossed.Embankment widening on the existing railway line has become a development trend.This method can not only improve the utilization rate of the line,but also save land and reduce economic consumption.However,when widening the existing line,the foundation and embankment of the original line should not be disturbed too much,which limits the construction of large and heavy machinery and equipment and large space.In the application of highway backfill engineering,this paper comprehensively studies the static and dynamic characteristics of two types of lightweight concrete in widening the railway embankment,and contributes to the application and promotion of lightweight concrete in widening the railway embankment.The specific research content is as follows:(1)Summarize the development status and existing problems of the widening of existing railway embankments by referring to domestic and foreign literature.Based on the research and application progress of foamed lightweight concrete and polystyrene lightweight concrete by domestic and foreign scholars,based on its lightness and self-reliance,the interaction between old and new embankments is reduced by reducing the upper load.As a starting point,research was carried out to apply it as a railway embankment filler to a railway embankment widening project.(2)The foaming rate,density and settling distance of the foaming lightweight concrete foaming agent are simply studied to determine whether the selected foaming agent meets the engineering requirements.The variation of compressive strength,splitting strength,flow value,and wet density with the amount of foam and the amount of fly ash replacement was studied,and the optimal mix ratio meeting the requirements of railway embankment fillers was derived from it.Orthogonal tests were performed on polystyrene lightweight concrete,and the effects of fly ash,slag powder,silica fume,particle size,binder,and fiber on their compressive strength,splitting strength,and frost resistance were studied.And the optimal mix ratio which meets the requirements of railway embankment filling is derived from it.(3)According to a project example,two types of lightweight fillers and traditional A / Bgroup fillers are respectively applied by numerical simulation.The additional settlement of different fillers on existing railway embankments is studied,and different fillers under dynamic loading are studied.Attenuation of dynamic stress and interaction between old and new embankments.