New Research On The Mechanism Of Frost Heaving Failure Of Canal Lining Blocks Of Large-Scale Trapezoidal Channel With Curved Bottom

The general characteristics of the water resources in our country is abundant but distribution unevenly in space and time, the average possession of water resource per person is little, and the level of integrated utilization is also low. Especially in the northern China, rice production accounts for46%of the total national output, but the water resources quantity accounts for only about10%of the national total water, so to establish the water-saving society and to build the water-saving buildings are imperative in most of north china where the water resource is shortage and the contradiction between the supply and requirement are becoming aculeate increasingly. The most effective way of reducing of water loss is lining the channel. But the most region of northern China is situated in the seasonally frozen soil regions where the soil heaving during winter, while melting down during spring. Itcauses different form,, and varying degrees of frost-heaving destruction of the lining slab.This article was supported by the project of large and medium irrigation district project of Ministry of Water Resources "experimental study on the anti-freezing property of large concrete impervious structure with trapezoidal channel and curved bottom(Number:20081015)", based on the prototype in-situ observations of fourteen species different concrete lining plate with trapezoidal channel and curved bottom, meanwhile on the basis of literatures review and existing knowledge of permafrost rule, frozen heave mechanism, the dominating factor for the damage of the lining slab, the mechanical and ANASYS model for frozon heaving. The frost heave characteristics of the canal was studied during the two freezing and thawing time. This article revealed the new research on the mechanism of frost heaving failure of trapezoidal channel with curved bottom, which was according to the new discovery in text. The phenomenon was found in this text that is two lining slab in the same conditions and the sane size parameter turned out differently, one of them was cracked at the surface of lining slab, while the other one was intact with slab-soil separated. So the construction quality was considered to be one of the influence factors of cracked or not. Which means if the construction quality is perfect, the lining slab could be intact with slab-soil separated, whihe if the construction quality is general, the lining slab would crack. A new mechanical model of frost heaving damage with those above mechanism expounded was established, and on model-based, VB simulation program was procedured. This program was proved possible in experiment.The results show that:(1)The canal concrete lining slab with square hole wire mesh has smaller crack width then it not with wire mesh in thin lining slab that below10cm, while to the thick lining slab the crack width is larger for it with wire mesh.(2)The canal concrete lining slab with geomembrane has lager crack width.(3)The precast concrete lining slab has large crack width than cast-in-place concrete slab, and the small size of the casting the more fractures number..(4)crack widths are positive proportional to the thickness of canal liner plate, the width of crack increases gradually with the increasing of the thickness of concrete lining. And the crack widths are positive proportional to the negative accumulated temperature.(5)The thicker the lining slab, the more the crack residue, the low the crack position. (6)The preset cracks of lining slab at1/3projected depth is good at anti-freezing effects, but the construction process is complicated and increasing construction cost.(7)According to the predicted results, the lining slab would be thinner in the top than the bottom, when the construction quality was common.