Unclassified 



Srcuntv Classifi< 



DOCUMENT CONTROL DATA -R&D 



• lication of title. 



Naval Civil Engineering Laboratory 

 Port Hueneme , California 93043 



Unclassified 



IN-SITU STRENGTH OF SEAFLOOR SOIL DETERMINED FROM TESTS ON 

 PARTIALLY DISTURBED CORES 



NorFinVl^'january' 'lffl'- """May 19 72 



H. J. Lee 



August 1973 



31 



25 



„ P ro JE ctno YF38. 535.002.01.013 



TN-1295 



I (Any other number. 



Approved for public release; distribution unlimited, 



Naval Facilities 

 Engineering Command 



The major obstacle to rational design of seafloor foundations and anchors has been a lack of 

 good quality information on the bottom sediment engineering properties. Considerable engineering 

 property data have been obtained through laboratory testing of core samples, but most of these data 

 are of questionable validity because of the sample disturbance factor. To improve the usability and 

 credibility of laboratory test data, an experimental investigation was undertaken to determine the 

 extent of disturbance involved in seafloor soil sampling and handling. In-situ tests were performed 

 and related to comparable laboratory tests. The soils tested were from the Santa Barbara Channel 

 with a terrigenous (land-derived) origin. A technique based on earlier work was developed for 

 predicting in-situ shear strength on the basis of laboratory test results. Various disturbance 

 mechanisms including sampling, vibration, long-term nonrefrigerated storage, and water and air 

 expansion were investigated and analyzed quantitatively. Strength reductions varying between 

 15 and 50 percent were observed to result from these disturbances. The in-situ strength prediction 

 procedure appears to be capable of compensating for all forms of disturbance except for those 

 developing as a result of gas expansion. 



DD 



1473 



Unclassified 



S/N 0101-807-6601 



