The discusser observes that in his experience, rockfills have attained pronounced settlements in a downward diagonal direction toward the toe, continuing for years and amounting to several feet in fills of commensurate size. In the Orkney Causeways, Scapa Flow, which were constructed of loose dumped rockfill clothed with heavy concrete blocks on the slopes as wave protection, heights were up to 60 ft and public roadways were built across the tops. The maximum top settlement, 2 yr after completion was 32 in. at the deepest point. Settlement appeared to be related to the square of depth. The maximum harizontal movement at the crest was 29 in. in 2 years. Both movements continued and aggravated the misalignment of the roadways that ultimately after several years had to be entirely reconstructed. Comparable settlements are described which occurred in dams in the western U.S. and elsewhere. The settlements are considered to have been caused by crushing for rock points bearing upon others throught the dam, which then allows the rocks to move toward the void spaces. It has been common practice to sluice the rock with monitors and sprinklers as it is being placed, the purpose water throught the construction perid. More recently it has been found feasible to compact large rockfills by mechanical means (rollers). These procedures have been accompanied by a marked reduction of subsequent settlements and movements.

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Filing Info

  • Accession Number: 00080525
  • Record Type: Publication
  • Report/Paper Numbers: Proc. Paper 10897
  • Files: TRIS
  • Created Date: Feb 27 1975 12:00AM