Mitigation of Disasters by Earthquakes, Tsunamis, and Rains by Means of Geosynthetic-Reinforced Soil Retaining Walls and Embankments

Abstract

The number of relevant case histories on the use of geosynthetic-reinforced soil (GRS) structures, including retaining walls and embankments, and their performance against large earthquake loads and heavy rainfalls is still limited. Their performance against tsunami is not well known, either. In view of this, in the first part, while focusing on the case histories during and after the March 11, 2011 East Japan Great Earthquake Disaster, Japan, performances of GRS structures against earthquake load and tsunami overflow are briefly summarized. Then, their application to rehabilitation works of the damaged structures is reported. In the second part, the development of L-shaped geosynthetic drain (LGD) is introduced, together with the relevant case history of rainfall-induced damage. In the LGD system, the water collected at vertically mounted geosynthetic drain sheet is drained through a horizontally installed drain. By having such an arrangement properly applicable to the drainage system, it is verified through a series of model tests and numerical analyses that the GRS structure is protected against any water invasion. It is also demonstrated that the use of steel slag in the construction of GRS structure is promising.