Abstract
Application of Electrical Resistivity Tomography (ERT) to quarry site bedrock above groundwater level at the Oyama dam and its evaluation are discussed in this paper. The method contributed to supplement boring investigation data, and to complete information acquisition on: geological features; distribution of targeted materials at the quarry site; and its quality. The Andesite is selected for aggregate of which concrete is produced for the dam. The rock is hard but with multiple cracks. At the beginning of excavation, it revealed that the bedrock in shallow part is not suitable for aggregate, and that it is required to conduct further investigation of the quarry site and revise the mining plan without delay in the project schedule. Groundwater was not found in the bedrock. To apply ERT above the groundwater level, water has to be filled in the boring holes. However, it was not possible due to geological features at the site. ERT was improved to meet the requirement. Filling the bubble in the holes was tested, and the investigation was successfully completed.
