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Title: Influence of soil properties and construction methods on the performance of homogeneous earth dams
Authors: Sherard, James L.
Keywords: Earth dams
Soil mechanics
Publisher: United States. Bureau of Reclamation.
Series/Report no.: Technical Memorandum ; 645
Abstract: The purpose of the investigation is to study the consequences of important departures from those practices accepted at the present time for construction of homogeneous earth dams. At the present time, essentially identical construction methods are usually employed for all soil types. The consequences of deviating from these methods, and particularly the influence of the embankment soil properties on these consequences, are not yet understood except in a very general way. Up to 1900, relatively few large earth dams had been built and little experience was available. In the period between 1900 and 1920, due largely to the expansion of irrigation in the western United States, a great number of earth dams were built. Because of lack of experience, there were no generally accepted methods available for the design and construction of these dams. It was a period of experimentation. In different places, widely varying designs and construction methods were used. Many of the dams constructed in this period failed in some degree. By 1920, engineering literature was filled with descriptions of earth dam failures and the profession had become thoroughly alarmed by their high frequency. In the early 1920's, the experience of the previous two decades already was strongly influencing earth dam construction practice. Failures were studied and dams were patterned after the successful structures. Because there were no means available for defining quantitatively the properties of fine grained soils, none of the descriptions of dam failures in the literature included the soil type. As a consequence, the methods of construction which evolved were not influenced by soil properties and were adequate for the worst soil type. By the early 1930's, slopes were made, in general, flat enough to eliminate danger from slides. About the same time, wide acceptance of Proctor's control procedures assured well-constructed embankments. As a result, the percentage of failures has been reduced practically to zero in the past 15 years. Yet, some of the dams which were constructed before 1920 with little or no compaction equipment and no moisture control have given adequate performance. This fact indicates that for some types of soils, and perhaps under other special conditions, present methods of construction are unnecessarily conservative . It was believed that a study of a group of these old dams might lead to a valuable correlation between soil type, construction method, and performance. Particularly for small dams, this correlation would justify relaxation of present construction practices for some soil types.
Description: Technical Memorandum
Gov't Doc #: Technical Memorandum 645
Rights: Approved for Public Release; Distribution is Unlimited
Size: 260 pages/77.31 Mb
Appears in Collections:Design and Construction Division. Engineering Laboratories Branch

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