INTRODUCTION 



The DOSIST (Deep Ocean Sampling and In Situ-Testing) cruises are 

 part of a continuing effort at CEL to investigate the engineering proper- 

 ties of marine sediments. The cruises consist of in-place vane shear 

 testing and sediment coring leading to laboratory engineering property 

 testing. The overall objective of the work is to develop laboratory 

 testing and coring procedures that can be used to obtain good estimates 

 of in-place engineering behavior of sediments. Coring and laboratory 

 testing is emphasized because it is more economical, more parameters 



(including long-term drained properties) can be measured, and a greater 

 range of subbottom depths can be investigated. In-place testing is 

 conducted during the DOSIST cruises to provide a basis for evaluating 

 the properties measured in the laboratory. That is, the properties 

 measured in the laboratory are compared with the in-place properties, 

 and techniques are developed for estimating the latter given only the 

 former. The difference between the results obtained from the two types 

 of measurements is termed sampling disturbance. The procedures used for 

 obtaining in-place properties using results of laboratory tests are 

 termed sample disturbance correction techniques. 



One sample disturbance correction technique was presented by Lee 



(1973a). It involved measuring the residual negative pore water pressure 

 retained by cored samples and using the relative magnitude of this 

 pressure as an indicator of the property changes that occurred during 

 coring and handling. Good correlations between degree of disturbance 

 and the residual pore water pressure were found for cohesive marine 

 sediments. Other sample disturbance correction techniques have also 

 been proposed (Ladd and Lambe, 1963). 



OBJECTIVE 



The objective of this interim report is to present and analyze the 

 results of in-place and laboratory tests conducted on typical ocean 

 sediments from the Western North Atlantic Ocean. A final report to be 

 prepared in about one year will recommend procedures for coring, testing, 

 and estimating the in-place behavior of most of the typical deep ocean 

 sediment types. 



A secondary objective of DOSIST II was to obtain the strength 

 properties of three sites where the CEL 20K anchor is to be field-tested. 

 The results presented in this report can be used to predict the holding 

 capacities of the anchors prior to the field tests. 



