CSG method using muck excavated from the dam foundation

Abstract

Cemented Sand and Gravel (CSG) is a material prepared by simple mixing of rock-based raw materials such as muck and riverbed gravel together with cement and water. CSG is being studied with an intention of making full use of site-generated materials. The CSG method can be used for dam construction to reduce construction costs and environmental burdens. In a counterweight fill work (fill volume of about 1,300,000 m3) to prevent a landslide around the reservoir of Takizawa Dam, an open channel was constructed by the CSG method to a temporary diversion facility of the Nakatsu River. Muck excavated from the dam foundation was used as a CSG material to suppress the cost of landslide prevention and topographic alteration. Wide variations were found in the test results of CSG properties, such as density and compressive strength. The quality of CSG is affected by various factors including grain size distribution, water content, cement mixing method, and compaction method. The muck used for the construction work contained top soil and severely weathered rock and thus had high content of silt and clay; this greatly affected the production and compaction of CSG.