Research On Soil Temperature Change Law In Seasonal Frozen Area And Freezing Damage Of Water Ank Engineering

The seasonal frozen soil area is widely distributed in China.Affected by the cold climate in the seasonal frozen soil area,the soil is frozen,and the corresponding depth of seasonal frozen soil layer is formed in different years.At the end of the cold period,with the rise of temperature,the soil gradually melts,and the seasonal frozen soil layer gradually thins down to complete melting.At the same time,the soil freezing effect also weakens and disappears.At present,there are few studies on the variation of soil temperature in seasonal frozen soil layer in China.Therefore,based on the measurement of soil temperature in different depths of seasonal frozen soil layer by using temperature observation equipment,this paper explores the variation law of soil temperature in each layer under the influence of external temperature,and provides reference for the basic research of seasonal frozen soil.In addition,the volume expansion of frozen soil will cause damage to the structures in contact with frozen soil,especially the soil layer in contact with water including water bank retaining wall,slope protection has high water content,sufficient external water supply,sufficient soil freezing conditions and strong frost heaving,which is more likely to cause frost damage of water bank structures.In addition,the ice sheet formed in the cold period of the plain type reservoir produces ice pushing at the end of the cold period,which is also an important reason for the failure of water bank structures.In order to explain the Frost Heave Mechanism of the ice wall in Changchun City during the freezing period,two measures were developed to explain the water heave mechanism of the ice wall in Changchun City.The main contents of this paper are as follows:(1)Three groups of stations were set up in the playground of Changchun Institute of engineering and Nanhu Park.Professional drilling equipment was used to drill 2.05 m,1.45 m,1.2 m,1.1 m,0.9 m,0.8 m,0.6 m,0.5 m,and the diameters of different depths were 0.02 M The soil temperature data of different depth layers in different periods(2019.9-2020.05)were recorded by toprie temperature observation instrument,and the daily temperature data of Changchun area in the same period were collected and recorded,and the relationship curve of soil temperature and air temperature in observation period was constructed.The comparative analysis shows that: the soil temperature of each layer has a cooling low temperature heating process corresponding to the continuous cooling stable low temperature rising stage of the external temperature during the observation period;the soil freezing depth also experiences three periods of variation,namely,increasing,peak value decreasing,until disappearing,and the maximum soil freezing depth is measured to be between 1.1 m and 1.2 m during the observation period;(2)Based on the data of frost heaving displacement of water bank retaining wall and the temperature data of the same period,the relationship curve between temperature and frost heave horizontal displacement of water bank retaining wall is constructed.Through comparative analysis,it is found that excessive horizontal frost heave displacement is the main reason for the damage of water bank retaining wall.In addition,the horizontal displacement of frost heave is different with different wall forms.Among them,the external convex wall is in a favorable "positive arch" stress state,and its frost heave horizontal displacement is smaller than that of the inner convex wall,and its frost heaving deformation resistance is strong,so it should be popularized in the construction of water bank;while the inner convex wall has large frost heave deformation,weak frost heave deformation ability,and is easy to be damaged by freezing damage,so it should be avoided;(3)Based on the field observation of the ice pushing in Xinlicheng Reservoir and the previous experience,the causes,formation process and interaction mechanism between the later stage and the slope protection are analyzed.New anti icing measures are developed for the phenomenon of ice pushing,and the anti ice pushing effect is verified.