require still more complex state-of-the-art advancements, for example, 

 an underwater pile emplacement system. 



The necessary pump, accumulator, switching apparatus, and battery 

 package required for a 10-foot diameter prototype are within the ex- 

 isting state-of-the-art. Measurements were made of the quantity of 

 water pumped through some of the models under a head of 10 psi. The 

 power involved in expelling this water is about 0.002 watts for the 

 12-inch diameter footing. The requirements of a 10-foot diameter pro- 

 totype footing with a pump system operating at an efficiency of 10 per- 

 cent could be supplied by 14 pounds of lead-acid automobile storage 

 battery. This evaluation presumes the availability of specially design- 

 ed equipment. An alternate, empirical approach to determining the power 

 requirement, using off-the-shelf equipment, indicated a need for 120 

 pounds of lead-acid storage batteries. Thus, the concept is workable. 



CONCLUSIONS 



1. The seafloor preconsolidating foundation concept can be effectively 

 used for the support of sensitive and/or heavy undersea structures on 

 seafloor sediments. 



2. Laboratory model tests and supporting analytical work indicate that 

 use of the concept reduces the structure settlement by 80 to 95 percent 

 and doubles the vertical load capacity. Comparable improvements in 

 performance are expected for prototype in-situ foundations. 



3. Laboratory model tests indicate that use of the concept does in- 

 crease the foundation lateral load capacity, possibly doubling the 

 magnitude. The present failure model used for foundation lateral load 

 capacity prediction is not applicable to preconsolidated foundations. 

 Research is needed to develop such a predictive capability. 



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