Figure 46 indicates that a deadweight weighing Detween 20 and 25 HN 

 (4.5x106 to 5.5x10° lbs) will be required to drive a cutting edge system 

 necessary to resist the deep ocean 18 MN lateral load. The waviness of 

 the dashed curve is due to change in the number of intermediate cutting 

 edges in order to maintain a b/Z < 2. As indicated before, the cutting 

 edges must be maintained this close together to cause the lateral sliding 

 failure to develop in the horizontal plane of the cutting edge tips. 



Figure 47 indicates that the minimum embedment force is reauired 

 for a cutting edge length to anchor width ratio of 0.1. Embedment force 

 is actually the weight reauired on the seafloor (for zero line angles). 

 Thus, by minimizing embedment force, weiqht is minimized and efficiency 

 is maximized. This figure demonstrates that efficiency is maximized at 

 the smaller cutting edge lengths. This trend is very favorable in that 

 overturning should not be a oroblem with such a wide and sauat anchor 

 unit. Fiqure 47 indicates a reauired embedment force of 11 MN in order 

 to realize the 18 MN lateral load capacity. 



For a cateaory C soil, Figure 48 indicates aaain that shorter cutting 

 edges are more efficient, in fact, the ontimum Z/B ratio is Drobably less 

 than 0.1. For the deeD ocean environment, a cutting edge embedment force 

 of 11 MN is reauired to achieve the 18 MN horizontal holding capacity. 

 The subject anchor block would be about 22 m (72 ft) on a side. For the 

 Gulf Stream environment, a cutting edae embedment force of 117 MN 

 (26x10 lbs) will be required to drive the required skirts to achieve the 

 required 180 MN lateral load capacity. This driving force cannot be placed 

 on the seafloor at one time because the largest lift system known can 

 handle only 62 MN, half of that necessary, and that load only to 1500 m 

 water denth. This limitation in load handling canability suggests that a 

 deadweight anchor in category C soil subjected to a Gulf Stream loadinn 

 would necessarily: 



a. Incorporate a sophisticated ballastina system to increase the 

 submerged weight of the anchor once it was on the seafloor in 

 order to fully embed the cutting edges. 



b. Incorporate a means for adding mass on too of the anchor to 

 help weight the anchor and drive the cutting edges in a uniform 

 manner. 



c. Incorporate a second anchor system to orovide the additional 

 lateral load capacity reauired, a system such as lateral load 

 resistina anchor piles emolaced through the anchor block. 



Fiaure 49 indicates that for a category D soil (sand) the most effi- 

 cient section in terms of reauired submerged weiqht reauired for embedding 

 skirts is that with no cuttina edges. This phenomenon occurs because the 

 lateral load capacity of a deadweiaht on a non-cohesive (sand) material 

 is predominantly influenced by the in-water weiqht of the anchor block. 

 The use of cutting edges to drive the failure zone deeoer in the sediment 

 does little to increase the lateral load canacity. 



97 



