Study On The Electricity Tower Bearing Capacity Of Foundation Soil Under Extremely Snow And Ice Condition Of Central South District

In early 2008, most regions of China suffered a big of snow disaster. The power grid in central south district which is not affected by ice and snow disaster perennial was destroyed by the big of snow disaster. And transmission tower foundation also changed all forms of destruction. Based on the base tilt factor related theory basis, the temperature, moisture content, freeze-thaw cyclic number of frozen soil are the research main, the base tilt factor of transmission tower is the core research. On the basis of the physical properties of frozen soil analyzed the relationship between the silty clay of central south district and three variables that are shearing strength, temperature, moisture content and freeze-thawcyclic number, namely at 0°~ 12°temperature range, the soil mass have the same moisture content, temperature is lower, the cohesion C and internal friction Angle phi is larger, the shearing strength of soil mass also gradually increased. When the moisture content was at 17% ~ 35% temperature range, the soil mass have the same temperature, moisture content is taller, its cohesion C and internal friction Angle phi are smaller, the shearing strength of soil mass also gradually decreased. When freeze-thaw cyclic number are less than 8, temperature and moisture content aer invariable, soil mass with the increase of number of freeze-thaw cyclic number, the cohesion C decreases. This paper analyzes the relationship between three factors which are temperature, moisture content and freeze-thaw cyclic number and the base tilt factor, it is concluded that a method to determine the base tilt factor of frozen-thaw soil. Using Terzaghi's formula of the limit equilibrium theory,the linear relationship between soil moisture at different temperatures and base tilt factor is established. Analysis the freeze and thaw temperatures, a method to determine the of base tilt factor. Based on the amended of base tilt factor formula, summarize that the proportional relation on the base tilt factor at different freezing temperatures and the base tilt factor at 0℃while the proportion relation on the base tilt factor at different thawing temperatures and the base tilt factor at - 12℃, which can give the base tilt factor at arbitrary temperatures. The paper use ANSYS7.0, under the environment of transmission Kentucky on snow and ice in different conditions shear and displacement, total strain was simulated analysis, simulation under the environment of internal force in ice and snow Kentucky changes, and corresponding conclusion drawn: Cladding ice load on the deformation of Kentucky has certain effect, and the surface temperature on the influences of Kentucky. As surface temperature decrease, the Kentucky maximum of displacement, the shear stress ratio of XY plane and Kentucky in hot - structural coupling conditions under the maximum stress ratio are tending to gradually increasing trend, and gradually become a steady value; In Kentucky load and wind load combination, Kentucky and basic contact point appears obvious stress concentration.This paper researches on the central south district in extreme snow disaster period, to properly determine the transmission of Kentucky foundation bearing capacity has certain practical significance.