Establishment And Application Of Mechanics Models Of Frost Heaving Damage Of Concrete Lining Open Canal

Our country has a vast territory, but lack water resources. While, saving water resourcesand sustainable development will be the only direction of our agriculture. Building channelseepage controlling engineering is one of the basic methods to realize the aim. There are more than 3/5 of our territories are belong to forest area, frost heaving damageis the main destroying forms of the channel in the region. Based on the observation andanalysis of large number of literature references, the history and the development of channelseepage controlling techniques are discussed in the paper. Give a presentation of theproperties of channel lining from the cross section and the structure of the channel; analyzedthe advantage of the curve type channel (such as U type section, trapezoid section with arcbottom and trapezoid section with arc foot) than trapezoid section channel by diagram anddata, put forward a new type section channel, para-trapezoid section; analyzed the damagemechanism and forms of different lining form, summarized the basic methods of controllingfrost heaving damaged, probed into the internal force calculation problem of lining structurethat discussed merely at before, expect to build a sort of mechanics model to serve theengineering. By thorough analysis of the damage mechanism of frost heaving on the concrete lining ofthe channel with trapezoidal cross section, this article presents the following conclusions:First, it points out that the calculating diagram of the lining plates of canal bottom and slopesare two–ends-simply-supported beam. Both of them are combined deformation membersunder the loads of bending and compressing. Second, it gives the mechanics models of frostheaving damage of the concrete lining plates of the canal with trapezoidal cross section. Andpresents the calculating formula of the control internal forces and maximal tensile stresses ofthe canal slope lining plates and the canal bottom lining plates. Furthermore, by consideringthe conditions of crack resistance of the concrete plates, it presents a series of calculatingmethods of frost heaving forces,position of expansion cracks,proper depth of the liningplates to prevent frost heaving and cracks occurrence , and checking calculation forprevention of frost heaving. Finally, it also elucidates that the intensity and direction of thefrost heaving forces,adfreezing forces and interactionally restricting forces, except for thegravity, are all interdependent , and they all can be expressed as the function of the adfreezingforces. Moreover the adfreezing forces is a comprehensive reflection of soil quality, negativetemperature and the status of moisture, thereby the mechanics models can be solved providedthat adfreezing forces is determined according to the practical experience or experiment.Subjecting the models to the field engineering calculating test shows its safety, rationality,simpleness and practicability.