Expendable Doppler Penetrometer.
Interim rept. Dec 73-Apr 75,
CIVIL ENGINEERING LAB (NAVY) PORT HUENEME CALIF
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An expendable penetrometer using the Doppler principle has been developed to expediently test seafloor soils at water depths to 20,000 feet. The velocity of the penetrometer is measured as it penetrates seafloor soils from the velocity record, soil penetrability and an estimate of soil strength are available. The penetrometer weighs 365 pounds, is 10 feet long, is 3-12 inches in diameter, and is easily deployed from a ship. Initial testing indicates that the concept of a Doppler instrumentation system is workable, that penetration can be accurately determined, and that deceleration can be ascertained. The penetrometer reaches a terminal velocity of about 80 feet per second which, based on penetration theory, is sufficient to obtain about 30 feet of penetration in a pelagic clay. It is anticipated that with experience the penetrometer in many cases can be used by itself to design direct-embedment anchorages, thereby eliminating the need for cores and geophysical measurements for this purpose. For other cases, the penetrometer will supplement soil coring and geophysical measurements for anchorage and foundation design. Author
- Physical and Dynamic Oceanography