Deformation Mechanism for the Pavement and Embankment of Jinsha Flyover of Yihuang Expressway

摘要

Embankment deformation such as slope sliding and lateral cracking will affect adversely the quality of the expressway, obstruct traffic flow and shorten the service life of the expressway. It is therefore necessary to study the deformation mechanism. The embankment of Jinsha Flyover is 8-11 meter high and the pavement and embankment had witnessed a substantial deformation since the expressway was put into operation. The deformation trend has been summarized and the cause of the embankment deformation has been subsequently analyzed by carrying out deformation measurement and analysis. It is found that the embankment deformation is due to the poor engineering properties of the backfill; the non-uniformity and certain degree of expansibility and contractibility of the backfill; high and steep embankment formation; and erosion. It is also found that the lateral deformation was caused by the interaction of these factors and stress concentration on the embankment slope. The embankment deformation can be categorized as four stages: ① Lengthways cracks appear on the slope surface; ② the cracks extend to the embankment shoulder; ③ the pavement yields lengthways cracks while the lengthways cracks on the slope and shoulder continue to expand; ④ The further expansion of these cracks and local slope instability results in separation between the pavement and embankment, which damages the expressway.