RCC Construction Aspects and Quality Control of Spring Grove Dam (South Africa)

摘要

The Spring Grove Dam is located in the Mooi River near Rosetta in the KwaZulu-Natal province of South Africa.It is a composite dam with a concrete gravity section in the river and an earthfill embankment on the fight bank.The concrete gravity structure has a maximum height of 37m and the embankment is 11 m high.The concrete dam has been constructed with an innovative optimised Roller Compacted Concrete(RCC) mix.Preliminary works related with the development of the mix design were presented in RCC2012 Symposium in Zaragoza (Spain).The simplification and advantages of this very workable RCC mix will be commented in this paper.The same mix could be either compacted in the dam with very few passes of the 10t vibratory rollers or vibrated against formwork and in confined areas with 50mm poker needle vibrators without any additional grout (called Ⅳ-RCC =Immersion Vibrated RCC).RCC placement in the dam started in July 2012 and partial impoundment started in March 2013.This article focuses on the dam construction issues and will analyse the quality control and instrumentation records,from early construction times to final impoundment.First spilling of the stepped spillway located on the central section of the RCC dam took place in March 2015.