An experimental study on the short and long-term behavior of pillars of Ryukyu limestone

The subsidence and collapses are of great concern and cause severe problems in urban areas, which are located above the abandoned mines or quarries when the extraction of ore or stones was carried out using the room and pillar mining method. Particularly the stability of pillars is one of the most important items in their overall stability. An experimental study is performed to obtain some fundamental data on the variations of multi-parameters on Ryukyu limestone pillar samples during deformation and failure for assessing actual performance of pillars in the field in short and long terms. Tests were carried out at Tokai University, Ryukyu University and Toyota National College of Technology. During tests, various parameters such as load, displacement, electrical potential, temperature and acoustic emissions are measured, which may be useful for monitoring the stability of abandoned mines and quarries. The authors report the results obtained from this experimental study and discuss their applicability in geo-engineering field.