Procedures for dealing with the sand layers require further develop- 

 ment. A new work unit initiated in FY76 will approach this problem and 

 utilize the data presented in this report. 



The measured field sensitivities (around 2) are quite low. The 

 sediments at Site IV appear to be well suited for supporting foundations 

 or resisting anchor pullout. 



SUMMARY AND CONCLUSIONS 



1. In- situ strength testing and coring were conducted in a proximal 

 turbidite and a foraminifera dominated calcareous ooze. Coring was 

 conducted in a deep ocean pelagic clay. 



2. The pelagic clay is quite weak and displays properties similar to 

 Pacific Ocean pelagic clays tested previously. 



3. The calcareous ooze has high in-place strength [2 to 4 psi (10 to 



30 kPa) ] which is almost completely lost during sampling. Consolidated- 

 undrained triaxial tests produce strengths which are about 70% of the 

 in-place values. The material is very sensitive (sensitivities of 5 to 10) 

 and would probably serve as a poor foundation or anchorage support. 



4. The proximal turbidites also have high in-place strengths that are 

 greatly reduced by sampling. Triaxial testing of silt layers accurately 

 reproduces the field strengths. The material has low sensitivity and 

 should provide an excellent support for foundations or anchors. 



5. The method of residual pore pressures cannot be used to correct the 

 strengths of highly foraminif eral oozes and proximal turbidites. Tri- 

 axial testing and the methods of Lee (1973b) appear to offer a suitable 

 means of disturbance correction for these materials. 



6. Techniques for dealing with seafloor sands require additional research 

 and development. 



7. Estimated strength profiles are given for the three sites so that 

 predictions of anchor holding capacity can be made. Tests of the CEL 

 20K anchor will be conducted at the these sites in the near future. 



ACKNOWLEDGMENTS 



Many individuals contributed to the successful execution of this 

 field and laboratory testing program. The help of the crew and officers 

 of the USNS LYNCH, the personnel of the Naval Material Center, Charleston 

 (particularly LCDR Waldrop) , Mr. Shun Ling of NAVFAC (FPO-1), Mr. Bache 

 of Roosevelt Roads Annex, San Juan, Puerto Rico, and F. 0. Lehnhardt and 

 A. Jackson of CEL is gratefully acknowledged. 



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