Amid high expectations for core sampling in fault fracture zones, our company developed a method for high-quality core sampling using microbubbles called Improved Fresh-Water Core Sampling or IFCS (patent No. 4025485). This method allows for the collection of core samples with minimal loosening from locations that are normally difficult to sample, such as fault fracture zones, loose sand layers, gravel layers, landslide clay layers, and underground layers below ground water. Additionally, continuous sampling can be conducted at diameters of 66-116 mm with daily drill depths of 3-12 m, for up to several hundred meters underground. Furthermore, slime is efficiently discharged through microbubbles, created with a commercially available high polymer paste. While maintaining drilling speed, it is possible to collect cores with sedimentary bands kept intact. There is no need to choose between salt, fresh, hard, or soft water for the drilling water; this method can also be used in both clear and muddy water. Since its development, IFCS has allowed us to provide high-quality cores, and has produced proven results in various surveys and research related to active faults, dams, geological disposal, stratigraphy, landslides, geothermal heat, and railway embankments.
Winner of the 2015 Japanese Geotechnical Society Kanto Branch Technology Award