Natural water content, Atterberg limits, effective pressure 

 (effective unit weight x depth), laboratory vane shear strengths, ratio 

 of shear strength to effective pressure, sensitivity and liquidity index 

 are presented in Figure 10. Laboratory analyses were performed according 

 to standard specifications (ASTM, 1964) . According to the Trilineal 

 Oceanic Soil Classification Chart (Shepard, 1954), the sediment taken 

 from Site 1 is classified as a clayey silt; however, according to the 

 Unified Soil Classification System (WES, 1960), the sediment varies 

 from a clayey silt (ML) to a silty clay (CL) (Table 5) . This 

 discrepancy is not surprising because the Unified System is based on 

 grain size and plasticity where as the Trilineal System is based 

 strictly on grain size. The sediment is fairly insensitive (low ratio 

 of undisturbed vane shear strength to remolded strength) with values 

 generally from 1.5 to 2.5 and exhibits liquidity indices that denote a 

 loosely deposited material. 



Table 5. Classification of soil at Site 1. 



Classification System 



Depth - Inches 



9-12 



21-24 



33-36 



45-48 



Unified Soil Classification 



ML 



ML 



CL 



ML 



Trilineal Soil Classification 



Clayey 

 Silt 



Clayey 

 Silt 



Clayey 

 Silt 



Clayey 

 Silt 



Laboratory vane shear strength data taken from Figure 10 were 

 superimposed on a plot of laboratory vane shear strength data (Figure 11) 

 previously obtained in conjunction with the evaluation of the in-situ 

 plate bearing device (Kretschmer, 1967). There exists a certain amount 

 of data scatter, but data from Core PP-1 follow the same general trend 

 as the previous results. Since the data are limited and the core samples 

 probably disturbed, it is unrealistic to make any definite conclusions 

 regarding the sediment behavior. 



In-Situ Test Data . Data from the cone penetrometer and vane shear 

 tests at Site 1 are presented versus depth in Figures 12 and 13. A 

 total of three cone penetrometer tests and two sets of vane shear tests 

 were performed. 



The original cone test data were reduced to straightline plots of 

 unit cone load for the projected cone area versus depth in the sediment 

 (Figure 12). The three cone penetrometer plots show small discontinuities 



11 



