Application of Ground Improvement to Restoring of the Mansory Wall of Yashima Castle

Abstract

The Yashima Castle remains were found recently in the Park of Yashima, Takamatsu City.The mansory wall of the castle is found to have greate historical value through archeological study.However,the castle wall was severly damaged due to sevier weather condition for long period of time. The Takamatsu City decided to restore the castle in orginal shape and structure and open to public uses. Through geotechnical survey, it is found that the foundation of the castle is unstable state and needs to stabilize through any kind of stabilizeing method.However, it is requred to sustain the original structure as using original materials.The method adopted is stabilization by MgO for upper portion of the fill behind the wall, and steel pipes for draining and reinfocemet of the lower portion of the wall.These methods were found to be effective throgh experiment and numerical analysis.The restoring works has been completed successfully using monitoring of deformations of the wall and strain mesurement of pipes.