The trapezoidal CSG dam combines the characteristics of a trapezoidal dam and the CSG (cemented sand and gravel) method to simultaneously rationalize the materials, design, and execution of dam construction. CSG materials are prepared using simple facilities to mix cement and water with materials easily obtainable from the dam construction site without gradation adjustment or washing, and the CSG method builds a structure by spreading the CSG material with a bulldozer and then compacting it with a vibrating roller. The Japan Dam Engineering Center led the development of the trapezoidal CSG dam, earning it the “National Land Technology Development Award for Excellence in 2009”.

The method has already been applied to the construction of cofferdams, auxiliary structures, and landslide countermeasure works, and has been used to construct two main dams, the Tobetsu Dam (Hokkaido Prefecture) and the Okukubi Dam (Okinawa General Bureau, Cabinet Office). The method will be used to construct a number of dams in future, and can be applied to a range of structures other than dam bodies. The Japan Dam Engineering Center holds various technology patents related to trapezoidal CSG dams and is the only organization able to perform related surveys, testing, design, execution planning and quality control. In the future, the JDEC will advance trapezoidal CSG dam technologies and conduct studies to overcome technological challenges.