Theoretical Calculation of Crack Performance in Continuous Track Slab in Severe Cold Area

In order to study the crack performance and its influencing factors in the continuous track slab in severe cold area, previous assumptions and mechanical models for the calculation of cracks in continuous track slab were modified according to their actual working states in severe cold area. Based on theoretical derivation and experimental verification, a methodology for calculating the crack performance in continuous track slab in different working conditions was proposed; the cracking law of the continuous track slab and the development trend of cracks with temperature drop were summarized. Results show that the crack performance in continuous track slab is closely related to the temperature drop amplitude and the spacing between adjacent cracks. The continuous track slab undergoes a primary cracking phase in a concentrated manner at a temperature drop of about 5 ℃. As the temperature drops further, the fixed zone length of the track slab will decrease to 0, and a secondary cracking phase occurs to the track slab in a single and sporadic manner; what’s more, the smaller the spacing between adjacent cracks is, the larger the temperature drop magnitude to initiate the secondary cracking of the track slab is. Tests show that when the spacing between adjacent cracks is smaller than 3.25 m, the track slab will not cause the secondary cracking at a temperature drop less than 37 ℃. The generation of a single crack only affects the mechanical properties of the track structure in the range of its left and right sliding zones, and if the sliding areas of the new and old cracks partially overlap, the new crack will cause a sudden decrease in the reinforcement stress and crack width amplitude of the adjacent existing cracks.