Abstract
Strong quake and the associated tsunami due to the 2011 off the Pacific coast of Tohoku Earthquake resulted in huge damage to many earth structures. A lot of coastal protection structures suffered heavy casualties due mainly to the erosion. However, the degree of damage to the river levees and embankments were different depending on the topography and the structural form. The main objective of this study is to collect basic information related to the seismic resistant and tsunami resistant characteristics of earth structures. To that end, site investigations and laboratory soil investigations on earth structures were performed at two locations of the central and southern part of Iwate prefecture. The investigation results show that subsidence related failure probably had taken place in the body of covered embankment with low penetration resistance and high water table. On the other hand, in the case of retaining wall made of tires, due to flexibility and ductility of the tires and the hoop tension that prevails within each individual tire prevented the wall from any damage due to erosion and the impact forces of tsunami.
