4. The sounding data (friction sleeve and cone pressure) are 

 repeatable from test to test. 



5. The sounding data can be interpreted readily to determine soil 

 stratigraphy (using Figure 12). This stratigraphy compares well to core 

 records and other data used for comparison. 



6. The XSP is a reliable device for gathering marine soil data to 

 assist the Navy in siting and designing facilities and structures in 

 marine cohesionless sediments. 



RECOMMENDATIONS 



1. The XSP should be maintained ready for use on projects 

 requiring geotechnical data. The device should be available to the Navy 

 to assist in surveying underwater sites and in designing of seafloor 

 facilities and structures. 



2. Evaluation of the XSP cone penetrometer should be continued as 

 it is used in various seafloors on these projects. Cores should also be 

 taken at sounding locations to continue evaluation and perhaps for 

 modifications of Figure 12. 



3. The XSP should be updated to include a piezocone. This piezo- 

 cone measures pore water pressure response, which has been shown to 

 affect CPT data (ESOPT, 1982). 



4. To increase the XSP's usefulness, the water-depth capability 

 and soil penetration depth capability should be extended. 



ACKNOWLEDGMENTS 



The contributions of Woodward- Clyde Consultants, Plymouth Meeting, 

 Penn. , and Fugro-Gulf , Inc. , Houston, Tex. , are appreciated. The at-sea 

 testing in Norton Sound was supported by the U.S. Geological Survey and 

 the Bureau of Land Management through an interagency agreement with the 

 National Oceanic and Atmospheric Administration. The 481st Transporta- 

 tion Company (Heavy Boat) U.S. Army Reserve provided ship support for 

 the tests in San Francisco Bay. The contributions of Dr. Philip Valent 

 (now of NORDA) in the early development is acknowledged. The capable 

 assistance of Mr. P. Babineau and the Technical Services Division of 

 NCEL in performing at-sea tests is appreciated. 



REFERENCES 



Begemann, H.K.S. (1965). "The friction jacket cone as an aid in deter- 

 mining the soil profile," in Proceedings, Sixth International Conference 

 of Soil Mechanics and Foundations Engineering, vol 1, University of 

 Toronto Press, Montreal, 8-15 Sept 1965, pp 17-20. 



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