4.5 Treated Site on Rokko Island
According to personnel from Fudo Construction Co., Ltd., a small area behind the sea wall at the southeast corner of Rokko Island was treated 2 to 3 years ago using sand drains in the alluvial clay and sand compaction piles in the overlying fill. A target post-treatment N-value for the fill of 15 blows per ft was established; however, a value of 20 to 25 blows per ft was actually achieved. Ground failure at this site developed, probably because of the large movements of the sea wall.