'•^^'ff^ 





Figure 25 . Slip surface for a deeply embedded 

 circular plate. 



As presented in the section on Tests and Results, NCEL and OS&E 

 have tested the anchor in several types of soils. In some instances 

 very good penetration did not produce adequate holding capacities. In 

 other instances, rather poor penetration produced relatively high 

 holding capacities. One extreme example is a series of tests conducted 

 at Seneca Lake by OS&E where penetrations were not limited. (This 

 particular test series was not part of the Laboratory program and is 

 not included in the test results.) An anchor system similar to the 

 NCEL vibratory anchor achieved exceptional penetrations (over 50 feet) , 

 but breakout resistances were minimal (less than 15,000 pounds). It 

 should be noted that in these tests a more powerful vibrator unit was 

 used and the support guidance frame was not used thus permitting the 

 vibrator unit to follow the fluke-shaft assembly into the soft sediments. 

 At the other extreme are tests conducted by NCEL in a sandy silt where 

 desired penetrations were not achieved, but results indicated that the 



48 



