Face Settlement Reduction in High CFRDs through Optimisation of Rockfill Compaction.
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
China’s government invests in hydropower and explicitly in larger dams. An increasing share of such large dams is globally represented by the type Concrete Face Rockfill Dam (CFRD) due to its safe behaviour at a relatively low construction cost. China is however building them higher than has earlier been done and the lack of worldwide experience requires thorough studies on their behaviour. This report presents a study of the Cihaxia dam that is to be built in the river basin of Huang He, regarding the optimisation of an increased rockfill compaction and its final effects on the settlements of the concrete face.
The settlements of a typical cross section of the Cihaxia dam are modelled with a Finite Element Method (FEM) program with varying values for a number of structural properties. The effect of each variation indicates what properties that will have the largest effect on the behaviour of the finished structure and points out where focus shall be laid when optimising the design of a high CFRD.
The outcome of the FEM analysis shows the static comportment of the rockfill body and its concrete face at two stages, at the end of construction and after reservoir impoundment. The difference between the two provides data on what effects the water load would cause, which constitute the main displacements of the concrete slabs.
It is evident from the obtained results that the most important of the studied parameters alongside with the level of compaction is the geometrical extension downwards and inwards of the zone subject to increased compaction. A higher degree of compaction will always produce a beneficial decrease of settlements but might not always be economically legitimate as costs rapidly increase with higher levels of compaction. An adequate level of a CFRD’s compaction increase can with advantage be determined by comparing different designs regarding the volumetric percentage to compact against the calculated decrease in slab deflection.
Place, publisher, year, edition, pages
, TRITA-LWR Degree Project, ISSN 1651-064X ; 2012:38
High CFRD; Rockfill Compaction Optimisation; Dam Analysis
IdentifiersURN: urn:nbn:se:kth:diva-171818OAI: oai:DiVA.org:kth-171818DiVA: diva2:844638
Master of Science in Engineering - Urban Management