Measurement of Frost Heaving Force on Ground Anchor and Soil Nailing

摘要

Ground anchor and soil nailing have been mainly applied in Japan as permanent and stable construction technology for unstable cut slopes. However, slope surface structures, such as ground anchor and soil nailing, may be damaged in cold districts like Hokkaido. Cut slopes in cold districts have experienced surface layer loosening due to the repetition of freezing and melting. Such a frost heaving phenomenon of the foundation is thought to be one of the causes of cut slope damage. However, the effects of the frost heaving pressure and time, acting to cause the damage, have not been confirmed, and as a consequence, no design or maintenance methods considering countermeasure technologies against frost heaving in slope surface structures have been established. Therefore, to study countermeasure technologies against frost heaving acting on slope surface structures, the load acting on ground anchor and soil nailing was measured in many places in Hokkaido. The results of the study enabled confirmation that the load acts on ground anchor and soil nailing in winter and is released in the early spring. Moreover, this phenomenon was repeated in the investigation period of more than multiple year years. Furthermore, it was found that the load does not act on ground anchor or soil nailing in regions with non-frost heaving soil, much snow, and cover soil.