The results presented for each site include (1) a general 

 description of the sediment environment, (2) the location of the samples 

 in the soil profile, (3) the percentages of sand, silt, and clay, 

 (4) the index properties, and (5) the vane shear strengths. 



These data are then discussed with respect to relevant information 

 on the seafloor environment (such as geomorphic characteristics of 

 the site) and compared with results from sites which exhibit similar 

 characteristics. Conclusions and recommendations complete the summary. 



The scope of this report is limited to the presentation of vane 

 shear strength data and sediment index properties and to a brief 

 description of the geological characteristics at the sites. 



SAMPLING AND TESTING PROCEDURES 



The following three sections present general information concerning 

 the procedures and types of equipment employed during sampling and 

 testing. The first two sections, CORING and VANE SHEAR TESTING, review 

 techniques utilized aboard ship; while the last section, INDEX PROPERTIES, 

 concerns methods employed in the NCEL Seafloor Soil Mechanics Laboratory. 

 This review is included because the results are presented for both 

 engineers and geologists. Unfortunately engineers and geologists 

 do not always use the same terminology. These sections will, it is hoped, 

 eliminate some of the confusion which might otherwise arise. 



Coring 



Deep-water (greater than 100 fathoms) "undisturbed" sediment 

 samples were obtained with gravity corers. Each corer consisted 

 of a steel barrel with a plastic core liner, a finger-type sample 

 retainer, and a cutting head. The length of the core barrels varied 

 from 1.8 to 3 meters. The corers did not utilize pistons during 

 sample recovery. Table 1 lists some of the corers' critical dimensions. 

 Gravity corer A functioned as the primary sampling tool, while the 

 trip corer acted as a weight for the trip mechanism. Gravity corer B 

 was employed several times to verify the soil profile at a site. 



Table 1. Corer Dimensions 





Barrel Diameter 



Outer Diameter 



Inner Diameter 





Corer 



BD (cm) 



of Cutting 



of Cutting 



Area Ratio 







Head, OD (cm) 



Head, ID (cm) 



(%) 



Gravity 











Corer A 



7.3 



7.9 



6.7 



39 



Gravity 











Corer B 



7.0 



8.2 



6.0 



87 



Trip Corer 



7.6 



8.2 



6.7 



50 



