On the Construction Technology for Increasing the Thickness of the Core Material Layer for Embankment Dams and a Rational Quality Control Method for Its Compaction

摘要

This paper describes the results of an experimental study on increasing the thickness of the core material layer for embankment dams,and a proposition for a rational quality control method for the compaction of the core material.In constructing the core material for embankment dams in Japan,the finished thickness (compaction layer thickness) used to be mostly 20 cm until the first half of the 1990s.If a thicker compaction layer of the core material becomes possible,then the construction period of embankment dams will be shorter,which,in return,will result in reduced construction costs.We performed an experimental study to increase the compaction layer thickness of the core material,using a vibrating roller and a material slightly coarsergrained to the extent that ensures a required imperviousness. This experiment confirmed that compaction layer thickness of 30 cm and more would be feasible.In addition,use of the RI densimeter (SRID),developed by the author's group and capable of large cubic measurement and easy multi-point measurement,revealed the compaction density of the core material,distribution characteristics of water content,and compaction density's dependency on water content.Based on these findings,we have proposed a quality control method for compaction of the core material,controlling the overall grain diameter. This new quality control method uses a statistical technique different from the traditional quality control method. This method was applied to three dams,with good results.