Transactions of the American Society of Civil Engineers

Constructed to a height of 275 feet in 1923-25 Dix Dam was then the highest rockfill dam built. Over a period of 33 years considerable data on leakage, maintenance, condition and settlement have been accumulated. This information is presented herein for applicable consideration in the design of similar future projects.

Features of special interest attending the design, construction, and performance of two rockfill dams 280 and 380 feet in height, more or less, are treated in this paper. Particular attention is paid to such novel features in the design and construction as have proved to be advantageous and successful as well as those which, ingeniously, though they may have been conceived by the designer, were found to be undesirable, if not detrimental. The principal reason for the latter was the fact that conditions in the field failed to fully conform to those anticipated. Through frank discussion thereof it is hoped to avoid repetition and to thereby render a service to the profession.

The 28-year service record of Salt Springs Dam, in terms of settlement, leakage, face cracks and maintenance is presented, The troubles at Salt Springs are traced to specific construction weaknesses. The design, construction and performance of the two Lower Bear River Dams is presented and compared to Salt Springs Dam.

The design of a 250-foot high sloping core rockfill dam, part of a hydroelectric project, was determined to facilitate construction with materials readily available at the site. The paper describes the site and discusses construction procedures and performance.

Mud Mountain Dam, White River, Washington, an earth and rock fill structure 400 feet high, has settled in the core zone almost exactly as predicted during design studies which were based on large scale consolidation tests. Differential settlement between core and shell zones caused cracking at the crest parallel to the axis of the dam with rock shells settling about 18 inches more than the core.

Especially valuable are reports on the behavior of rock fill dams to compare with the design assumptions. The many variable and sometimes unknown conditions which influence the design of fill dams are sometimes either over or under-emphasized and, therefore, misapplied. Only by comparing the results with the design assumptions can better dams be built. The authors have made this comparison on three TVA fill dams.

This paper briefly reviews the principles which govern the design of a rockfill dam and discusses six rockfill dams with which the author has been intimately acquainted since completion of the Nantahala Dam. Bear Creek Dam, one of these six, incorporates most improvements in design and construction learned from experience.

The design and construction of seven dams is briefly reviewed and performance is discussed measured in terms of leakage, settlement, control and passage of floods, operation, repairs and maintenance. Conclusion reached that sloping core rockfill dams so far designed and constructed have performed to entire satisfaction of owners and operators.

Site and materials data, design criteria, construction procedures and some performance records are presented in this paper on two zoned rock fill dams in British Columbia. One is founded on rock and the second on a mud slide.

This paper is confined to a discussion of rock fill dams having impervious zones of earthen materials. Terminology for various zones is suggested. The importance of thorough investigation of sites and materials is stressed, and reasons given from the standpoints of the designer and of the contractor. Design theories are lightly touched upon, since there is already considerable technical literature available on these. Construction problems are discussed; scheduling, river handling and choice of equipment are mentioned, and foundation treatment and placing of materials in the various zones are considered in some detail.

This paper describes the design and construction of the rockfill dam embankment portion of Kajakai Project. This dam, in Central Afghanistan, was economically constructed despite its geographic isolation. The feat required maximum use of locally obtainable materials and complete training of a native work force.

This paper describes the Lemolo No. 1 Rockfill Dam of the California Oregon Power Company. The dam, which was built during the winter of 1953-1954 and the spring of 1954, is a deck type with a reinforced concrete deck. The reservoir was partially filled in 1954 and was filled in 1955. The dam is relatively small and is of interest primarily because the north abutment was founded on soil consisting of a mixture of old talus, ancient streambed material and clay. A deck type rockfill dam founded on soil is unusual, if not unique.

This paper describes the construction of Cherry Valley Dam of the Hetch Hetchy Water Supply of the City and County of San Francisco. Cherry Valley Dam is of the central core rockfill type. The central core is composed of compacted decomposed granite and the rockfill is of freshly quarried granite, placed in lifts of 15 to 30 feet and sluiced. The performance of the embankment during the first two fillings of the reservoir is also described and measurements of the settlements and deflections are given.

The 361-foot high Paradela Concrete Face Rockfill Dam forms part of the hydro-power development of Northern Portugal. The paper discusses the selection of site and type of dam, describes the design and the construction details and procedure, and presents performance data.

Foundation conditions at the site of the Paradela Dam in Portugal and the various problems they presented are described. The paper discusses the arrangement of grout curtains and other treatment carried out to suit the geological conditions, and presents performance data on seepage control.

This paper describes a rock-fill dam with an asphaltic concrete deck representing a new concept in dam engineering. It sets forth the reasons for selecting that type of dam and deck and explains various aspects of design and of construction, especially as regards the asphaltic concrete deck. It cites the advantages and economy attainable with such type of dam construction.

Speed of construction and structural integrity were the chief advantages gained by the use of a steel-plate facing on a rockfill dam built in Venezuela in 1958. At present, steel-plate facing is seldom considered for use on earth and rockfill dams, although a number of such dams have been built in the past and have seen many years of satisfactory service. The principal reasons for not considering steel facing the dams have been concern about possible corrosion of the steel and cost. However, the advantages offered by steel-plate impervious membranes for dams are such as to justify the consideration of this type of construction under some site conditions. Experience with structures in the Western United States gives weight to this statement.

Construction of a closure dam for The Dalles project in 180 -foot depth of water with flows up to 200,000 c.f.s. presented a problem solved by the design and construction of a rockfill structure, two-thirds of which was built under water without use of cofferdams.

The Bersimis No. 1 hydroelectric power development in Canada involved the construction of two earthfill and two rockfill dams. This paper describes the site, design, construction, and performance of these dams.

This paper describes the design and construction of the rockfill dam portion of Brownlee Hydroelectric Project. Of unusual interest are: diversion of flood waters over the partially completed embankment; inclusion of large quantities of compacted small rock material in the dam; and construction of the embankment on 110 feet of river-deposited materials.

Design considerations and construction of the two approximately 300-foot high dams are discussed. All changes in design and construction from previous P. G. and E. dams have been made to lower the cost without affecting the safety of the dams. Wishon was filled in May 1958 and initial crest settlement data is presented.

Described in this paper are the problems pertaining to the design of a 450-foot high central core rockfill dam. Foundation excavation and preparations for diversion are now under way. The Derbendi Khan project consists of the rockfill storage dam, chute spillway, outlet works, and provisions for a future powerhouse. Diversion of the river was provided for by two tunnels that will serve the permanent outlet works and powerhouse after construction. A thorough field exploration and materials testing program provided a sound basis for the selection and design of the dam. Major problems were anticiapted and are being provided for as a result.

The design of a rockfill embankment for Cougar Dam involved a choice between a central-core and a sloping-core section. The initial decision was for a sloping-core section, but this was later reversed and a central-core section was adopted. The principal factor in making the final decision was the uncertainty as to the amount of water load settlement that could be expected in a rockfill embankment the height of the proposed dam and the susceptibility of a sloping core of compacted earth to rupture from the type of settlement that would occur.

This paper reviews present practices. It develops a definition, classification and terminology for such dams and for those using earth in addition to rock fill. It discusses the advantages of deck-type dams; also settlement and economy of rock-fill dams. In its appendix it lists rock-fill dams constructed in the United States and in Foreign countries.