As mentioned in the first two paragraphs, the torsional resistance 

 of the spring to vane rotation was related to the strength of the 

 soil. This interpretation was based upon the following equation: 



2 

 T F = -y- (1 + W ) S (2) 



where T = the failure torque (gm/cm) 



r 



D = vane diameter (cm) 



H = vane height (cm) 



2 * 

 S = vane shear strength (gm/cm ) 



By applying the appropriate torque factors, the original and remolded 

 vane shear strengths were calculated. 



Difficulties associated with performing certain index property 

 classification tests aboard ship prevented immediate completion of the 

 soil test program; therefore, each sediment section was visually 

 classified, labeled, and stored at 4 degrees Celsius in containers 

 filled with seawater until they could be returned to the United States. 



Index Properties 



When the sediment samples arrived at NCEL, personnel from the 

 Seafloor Soil Mechanics Laboratory performed a series of tests to 

 define the sediment index properties. These laboratory tests included 

 the determination of original water content, grain size distribution, 

 specific gravity, carbonate carbon and organic carbon contents, and 

 Atterberg limits. 



The number of laboratory tests on each core varied. When the 

 material within the core appeared homogeneous, a single representative 

 sample was selected from the core for grain size, specific gravity, 

 and carbonate carbon and organic carbon contents tests. If major 

 variations (evidenced by change in color or noticeable change in 

 grain size) were detected, a representative sample from each soil 

 type was tested. The laboratory test program established the 

 original water content and Atterberg limits at every interval upon 

 which a vane shear test was performed. 



The following paragraphs present a general review of the 

 laboratory testing procedure. In most cases these procedures follow 



S is considered to be approximately equal to the undrained shear 

 strength of the soil, c. 



