The authors report an earthquake response analysis of a tailing dam with a foundation composed of jointed rock masses. The non-linear deformation characteristics of the rock joints are assumed to be combinations of different angles of joint sets using the Multiple Yield Model introduced by Sasaki et al. (1994). The non-linear deformations of a joint in the normal direction and in the shear direction are dependent on the confining pressure presented by Bandis et al. (1981) and Kulhawy (1975), respectively. The results indicate that the tailing dam is sound and that the water-gathering basin with a gravity-type wall should be collapsed. They also show that the additional small gravity dam is sound when the countermeasures considered are taken, and that acceleration at the gravity-type wall is reduced by one-third compared with the structure with no countermeasures taken.
In 1955, the Japan Atomic Agency constructed a tailing dam to contain the debris and debris water from a mine in order to provide advanced water treatment of the mineral poison. Later, in 1980, the Agency reconstructed an extension of the dam to a height of 1 m. As of this writing, the volume of debris in the dam has reached 3.6 × 104 m3. According to the Headquarters for the Promotion of Earthquake Research under the Japanese Ministry of Education Culture, Sports, Science and Technology and the Division of Disaster Prevention in Okayama Prefecture, the existence of active faults near the dam site indicates that several earthquakes have occurred. The authors have therefore evaluated the stability of the dam using the Multiple Yield Model (MYM), a non-linear finite element analysis of joint sets in rock masses introduced by Sasaki et al. (1994). This paper reports the results of the analysis on the present state of the dam structure and state of the dam countermeasure design determined through earthquake response analysis.
