Unclassified 



Srcunlv Classification 



DOCUMENT CONTROL DATA -R&D 



Naval Civil Engineering Laboratory 

 Port Hueneme, California 93043 



Unclassified 



ENGINEERING PROPERTIES OF A PELAGIC CLAY 



April 1972 - January 1973 



middle initial, last name) 



H. J. Lee 



August 1973 



28 



13- 



YF53. 535.002.01.013 



TN-1296 



3RT NOIS) (Any other numbers that may be assigned 



Approved for public release; distribution unlimited. 



Naval Facilities Engineering 

 Command 



Pelagic clay is a common ocean soil type covering over 30 per- 

 cent of the seafloor. Two high quality box core samples of pelagic 

 clay were obtained and subjected to index and engineering property 

 testing. The results of tests on both cores were similar indicating 

 little areal variability. The shear strength near the soil-water 

 interface was about 1 psi, a relatively high value, and the soil was 

 found to be virtually incompressible up to a compressive stress of 

 about 4 psi. When remolded, the strength of the soil was signifi- 

 cantly decreased, by as much as a factor of 6. The soil was also 

 found to be very compressible beyond a stress of 4 psi. A technique 

 was developed for using triaxial test results to derive shear 

 strengths below the level of sampling. The resulting strength pro- 

 file indicates a very gradual increase of strength with depth. 

 Implications regarding the use of direct embedment anchors are 

 discussed. 



DD 



,1473 



Unclassified 



S/N 0101-807-680 1 



