The Research Of Replacement Depth Of Canal Foundation In The Cold Regions

The distribution area of permafrost accounts for about 23% of the land, mainly distributed in Russia, Canada, China and Alaska in the United States, etc, among which the distribution area of the permafrost in our country accounts for about 10 percent, it accounts for 21.5 percent of our land area, and our conntry is the third permafrost superpower. Meanwhile the permafrost in China mainly distributed in the qinghai-tibet plateau touted as the world third pole which is located in the middle or low-latitude. Seasonal frozen earth generally distributes in the region than 24°atitude, in our country seasonal frozen earth distribution area accounts for 53.3 percent of our land area. Therefore,the permafrost is also considered as the precious land resources.In water conservancy engineering foundation construction, channel engineering is the most basic and the most used one. In the the process of channel design the main problem we encountered is the frost heaving damage in the channel. According to the observation of built channels, in Xinjiang the anti-seepage channel has locally appeared frost heaving damage, whic light affected the impervious effect of the channel of and the durability of the lining,or even resulted in the water repair in channels, which directly affects the agricultural production.The thesis firstly described the freezing mechanism of canal lining in seasonal frozen soil area and failure features, summarized the significance of channels anti-frost, the composition of frozen soil, research status and mechanism of moisture migration in freezing soil, then, through ANSYS finite element software the frost heaving damage mechanics model was built in the trapezoidal concrete lining channel. Combined with the engineering practice, the thesis did the thermal stress simulation focusing on the frost heaving in trapezoid lining channels, some conclusions were drawn:(1)The replacement measures of channel can not affect the distribution of temperature field.(2) After filling the channel the horizontal displacement is more uniform, but without filling the channel the horizontal displacement is changed greatly and uneven.(3)When the replacement of channels is to 80cm, whether it is slope boards, sunny or floor planes, frost heave has been reduced significantly, frost heave force is perpendicular to the freezing front.(4)When concrete channels have a replacement, whether horizontal or vertical stress have been reduced, but it can not change the phenomenon that stress concentration occurs in the top of Yin and Yang hill, both sides of channel bottom...