17- 



1± 



Anchor line broke; actual 

 fluke capacity would have 

 been higher, raising line. 



Numbers indicate anchor 

 test; see Table 3. 



SiltySand Stiff Clay SoftClay 



Figure 18. Relationship between the parameter tj (holding capacity/kinetic energy) and soil type. 



(short-term) as much as a large fluke. One possible 

 explanation for this is that the large flukes create 

 much more soil disturbance during dynamic penetra- 

 tion than do the small flukes. A method of counter- 

 ing this phenomenon would be to wait a day or week, 

 depending upon the rate of strength regain through 

 thixotropy or reconsolidation, to fully load the 

 anchor flukes. Also, in a highly sensitive seafloor 

 material the long-term capacity would far exceed the 

 measured short-term capacity. Another distinct 

 possibility is that the large flukes are not keying or 

 take considerably longer to key than expected in soft 

 sensitive clay. Both possibilities, disturbance and poor 

 keying behavior in soft clays, are being explored 

 through small-scale field tests and laboratory model 

 tests. 



The parameter -q can be used to get a better idea 

 of what force would have been required to pull out 

 the fluke in test 17 if the line had not parted. 

 Assuming a medium value of 10 x 10"^ for 77 instead 



of the recorded 8 x 10"-^, the short-term holding 

 capacity would have been 72 kips, which is 25% 

 greater than the peak recorded load of 58 kips. If this 

 plot could be verified with more data, then it would 

 provide a quick method of determining a specific 

 range of short-term holding capacity with only 

 limited site information. It is probable that the 

 parameter tj can be related to a specific seafloor 

 property, possibly undrained shear strength, to more 

 clearly express the short-term behavior of propellant- 

 actuated embedment anchors. This possibility and 

 others are being fully explored at CEL; the results of 

 the theoretical and empirical investigations will be 

 reported at a later date. 



Performance of Device 



The 20K anchor has operated successfully in 

 clays, silts, sand, rock, and rock conglomerate. 



22 



