Experimental And Numerical Simulation Of Frost Heave On Integral Long-span U-shaped Concrete Lining Canals

In seasonal frozen soil area,soils freezing in winter and induced frost heaving damage to many types of engineering structure,include the canal of irrigation distraction.This dissertation proposed a new type of concrete lining,integral long-span U-shaped concrete lining,using its good frost resisting ability in order to alleviate the degree of frost heaving damage,based on deeply analysis of frost heaving failure mechanism of lining.Through cancelling the rigid seams between slabs partly to strengthen the structural integrity and lighten the frost heaving damage of canal linings.Summarized the research results of frost soil,using soil freezing experiment,large-scale frost heave centrifugal modeling test,prototype measurement,theoretical analysis and numerical modeling to study the influence of temperature and water to soil frost heaving ability;research the frost heave characters of small U-shaped concrete linings,include the frost heave force and deformation;realize the frost heave characters of the integral long-span U-shaped concrete lining,and reveal its damage mechanism;analysis the frost heaving effect of these U-shaped concrete linings using numerical simulation.The main research conclusions and achievements are concluded as follows:(1)Freezing temperature of Silt of Ningxia Yellow diversion irrigated area is about-0.21 ?,through the freezing and thawing cycle test.(2)Different structural characters of small U-shaped concrete linings due to arrangement form of rigid seams between adjacent slabs,is primary cause of linings' widely different failure mode.The rigid seams not only changed integrity of lining,but also changed the direction of shearing force and bending moment under frost heaving,influenced the mechanical property of linings ultimately.Hence,rigid seams are the most weak part of lining,.(3)Given out the internal force formulate of every part of lining under frost heaving through establish the mechanical model of small U-shaped concrete lining,in order to procedural design.(4)Frost heave centrifugal modeling test are carried out,it reveals law of frost heave action in centrifugal modeling.All the linings were lifted during the test,the deformation of bottom of lining,up to 16mm,larger than slab slope which were only 4mm.Meanwhile,the horizontal deformation of its cross section reaches to 5mm inwards.(5)The frost heave deformation along horizontal and vertical has few relationship with the slab span.There is longitudal and symmetric deformation with the increasing of slab span,the deformation of the fringe is larger than inner.These research results enrich the content on frost heave deformation and failure characteristics from U-shaped canal in the research field of irrigation building frost heave injure with seasonally frozen environment,provide technology support on constructure high standard farmland and keep on steady development of modern agriculture in arid areas.