The Application Of Chair-type Wall In Expressway Construction

The high steep slope nearby K131of Algeria East-West highway is made by impropercutting during construction. It needs to be protected by a retaining structure. This retainingstructure is a new type of steel-reinforced concrete retaining wall. According to EUROCODEThis paper researches this retaining wall from the following parts: analyze the globe stabilityof the slope with retaining wall; use FEM (finite element method) to simulate various casesand stages, and assess the stability of retaining wall; distribute the steels in differentconstructional members of the retaining wall based on the moment and sheer force calculatedby FEM.This essay studies the high steep slope caused by the building of beam construction site;and design the structure of chair-shaped wall, as well as the structural calculation.The contents and conclusions are following:1）、The design of the size of the retaining wall: the height of wall is determinated by thedifference between road shoulder and the foot of embankment. The depth of foundationunderground is1.5m. In order to ensure the temporary slope is stable, the embankment ismade with a gradient1:1from the slope foot and a platform more than2.5m is built for thechair to make sure the chair is stable。2）、The distribution of steels in retaining wall: the moment and shear force are computedby FEM. The method of distribution is from the6and7chapter of BAELmod99.3）、The temporary supporting structure of the retaining wall: according the results ofFEM, when the completion of TVO (a kind of untreated gravel) under the chair and lowerpart wall (underneath corbel), the chair may not be stable; so a temporary external supportingstructure with163kN/msupporting strength is necessary.4）、The difference and commonness between the Chinese and European standard forretaining wall: the basic theory and method are in agreement. The major contradictions are theconsideration of seismic force, partial factors for load combination, global safety factors,ground bearing strength and eccentricity, etc. Additionally, for steel-reinforced concrete retainwall, the calculation of the strength of wall and distribution of steels are slightly different.