INTRODUCTION 



This paper is the first of three Hydrographic Office reports describing results of 

 an investigation of engineering and mass physical properties in 35 sediment cores 

 collected from Hydrographic Office oceanographic ships (Frontispiece) in 1958 and 

 1959. Principal objectives of this paper are to acquaint oceanographers, engineers, 

 and military personnel unfamiliar with soil mechanics with: (1) methods of core 

 collection and testing for physical analysis of sediments, (2) the range of measured 

 shear strength in 30 cores, strength versus depth relations, and general validity of 

 the measurements in light of factors affecting strength of sediments, (3) the practical 

 application of using shear-strength information to compute ultimate bearing capacity 

 of sea-floor sediments, and (4) the practical aspects of consolidation of sea-floor 

 sediments under applied loads. 



The second report in the series (Richards, in preparation) describes and discusses 

 the mass physical properties of the 35 cores investigated in this study and relates 

 these properties to depth. Tabulated laboratory test and computed data are contained 

 in the second report. A third report considers computed and laboratory measured con- 

 solidation of these sediments. 



The first series of cores collected expressly for soil mechanics and soil physics 

 tests were obtained in the spring of 1958. In June, arrangements were made by the 

 Hydrographic Office to have cores tested in the Soil Mechanics Laboratory of the 

 Navy's Bureau of Yards and Docks (BUDOCKS), and testing began the same month. 

 Since then, many more cores were added to the test program at BUDOCKS. Analysis 

 of results of laboratory tests began during 1958. This paper was started during the 

 same period while I was an oceanographer with the Hydrographic Office; it has been 

 concluded during a leave -of -absence while I was a National Academy of Sciences- 

 National Research Council Postdoctoral Resident Research Associate* at the U.S. 

 Navy Electronics Laboratory in San Diego, California^. 



Skempton (1953) and Terzaghi (1955) are recommended for a geological orientation 

 to some fundamentals of soil mechanics; those readers wishing a more exhaustive 

 treatment are referred to standard texts: for example. Capper and Cassie (1960), 

 Hough (1957, Spongier (1960), Taylor (1948), Terzaghi (1943), Terzaghi and Peck 

 (1948), and Tschebotarioff (1951). 



At NEL a decade ago the problem of bearing capacity of fine-grained sediments was 

 considered briefly (Butcher, 1951). 



'■'The author was assigned recently to the Office of Naval Research Branch Office, 

 London W.l, England, 



