Koyama, Tomofumi (Kyoto University) | Katayama, Tatsuo (KANSOTechnos, Co. Ltd.) | Tanaka, Tatsuya (Obayashi Corporation) | Kuzuha, Yuji (Japan Atomic Energy Agency (JAEA)) | Ohnishi, Yuzo (Kyoto University)
The importance of rock mechanics associated with geological storage of CO2 (GCS) is now widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO2 repository (as well as how it could impact the public perception of GCS). To date, no notable seismic event has been reported from any of the current CO2 storage projects, although unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large power plants will require injection at a much larger scale. For such large-scale injections, a staged, learn-as-you-go approach is recommended, involving a gradual increase of injection rates combined with continuous monitoring of geomechanical changes, as well as siting beneath a multiple layered overburden for multiple flow barrier protection, should an unexpected deep fault reactivation occur.
Leelasukseree, Cheowchan (Chiang Mai University) | Pipatpongsa, Thirapong (Tokyo Institute of Technology) | Khosravi, Mohammad Hossein (Tokyo Institute of Technology) | Mavong, Narongsak (Tokyo Institute of Technology)
Goel, R.K. (Central Institute of Mining & Fuel Research) | Dwivedi, R.D. (Central Institute of Mining & Fuel Research) | Viswanathan, G. (Chenani-Nashri Tunnelway Ltd) | Rathore, J.S. (Chenani-Nashri Tunnelway Ltd)
Thaya, S. (Tokyo Institute of Technology) | Pipatpongsa, T. (Tokyo Institute of Technology) | Takahashi, A. (Tokyo Institute of Technology) | Doncommul, P. (Electricity Generating Authority of Thailand)
The large deposits of freshwater snail fossils aging around 12-13 million years has been discovered at Mae Moh lignite mine in the northern part of Thailand. The preserved area of snail fossils with layers of up to 12 meters deep in the mining area has been set aside; however, there is a concern about the influence of mining activities in the vicinity area as well as excavations at a deeper depth. Therefore, detailed studies of the strength characteristics of snail fossils become necessary. The present study reported part of an investigation program in which direct shear strength properties of snail fossils were focused through the direct shear test with constant vertical stress under wet and dry conditions. The intact and disturbed samples were collected from a subsurface of a location deposited outside the preservation area. The effects of vertical effective stress, water, overconsolidation, and multi-reversal shearing on the shear strength properties of snail fossils were examined. The results show that the stress ratio decreases with increasing the vertical effective stress and the number of shearing. The presence of water appeared to have an impact on strength properties to some degrees. In addition, there is a rise in the stress ratio as the overconsolidation ratio increases.