Selected clay borrow materials were obtained from an old lake bed to form a flexible core in the construction of Cedar Springs Dam, a 215-foot- (66-meter) high zoned earth- and rock-filled structure, San Bernadino County, California, USA. The dam is designed to withstand a mazimum credible accident, which included 3 to 5 feet (0.9 to 1.5 meters) of lateral or vertical displacement that could possibly occur within the foundation of the dam during a strong earthquake. The clay borrow was selected after an extensive investigation for plastic material that could deform without cracking or losing strength. Results of soil tests on materials placed in the dam differed somewhat from the results of soil test data used in design. However, based on the tests and upon the performance of the dam structure since 1971, the inplace material met the design requirement and is able to maintain its integrity as an impervious membrane. The design objective required the core to be flexible in nature and to be able to adapt to large deformations without cracking. The suitability of the inplace clay core was measured by its Atterberg limits and grain size gradation. Although the clay core was more clayey and more plastic inplace than predicted, it is believed to meet the design intent. Factors leading to the differences between the design soil test results and the inplace material soil test results are principally attributed to differences in handling of the materials. The source of the selected clay fill was approximately 25 miles (40 kilometers) from the dam. The contractor's construction procedures required the stockpiling and moisture the final analysis, the laboratory program should serve as a was re-excavated and placed in the dam. There were measurable differences in test results with various amounts of handling of the clay materials. These differences have been noted by others and are generally anticipated and quantified for design purposes by adjusting the testing program to simulate mechanical mixing of clay particles and methods of adding water anticipated during construction. In the final analysis, the laboratory program should serve as A model of the construction processes utilized. (a) (TRRL)

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 119-125

Subject/Index Terms

Filing Info

  • Accession Number: 00311806
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-7277-0069-3
  • Report/Paper Numbers: Proceeding
  • Files: ITRD, TRIS
  • Created Date: Jul 22 1980 12:00AM