Design Criteria for Variable Rigidity Sections of Approach Embankments to Bridges and Overhead Crossings

Abstract

AbstractThe development of rail transport involves the elimination of barrier places, which include the transition sections from the artificial structures to the subgrade. The existing normative solutions on the arrangement of transitional sections with variable rigidity refer mainly to the new construction. And during development of new types of crossing sites which allow performing works on their arrangement without movement restrictions, there are questions of design and estimation of nonuniformity of approach embankment settlement on crossing sites. To solve the emerging issues, it was proposed to evaluate the transition sections “smooth approach”—the pattern of change in the longitudinal slope on the section of variable rigidity, which does not cause significant dynamic effects on the track structures and rolling stock when the latter approaches the railway bridge structure. In order to obtain the criteria for assessing the "smooth approach”, the nonuniformity of approach embankment settlement in the area of its interface with the bridge for the known structures of the transition sections has been investigated. Functional dependences of changes in the vertical deformation of the main site on the length of the section with variable rigidity were obtained. Differentiation of the obtained functional dependences by the length of the section of variable rigidity allowed revealing the law of change in the increment of vertical deformation by the length of the approach embankment section. In other words, the assessment criteria of "smooth approach" to the railway bridge construction in the form of the law of change in the nonuniformity of the slope angle of the main platform on the section with variable rigidity has been obtained. The principle of designing new types of variable rigidity sections using the developed criteria has been proposed.KeywordsRail transportTransition sections from the artificial structures to the subgradeBridgeOverhead crossings