Author(s): D. Masterson; W. Graham
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Abstract: In the early 1970's oil and gas exploration efforts were beginning in the Arctic offshore and tools were sought to obtain the engineering strength properties of ice, properties which were required for the determination of ice forces on structures and ice bearing capacity. It was desirable to have a tool which would yield strength and stiffness at 0.3 to 0.5 m intervals through the depth of the ice cover since they vary with depth. Dr. Hans Kivisild first suggested in 1971 using the Menard Pressure Meter as a tool for obtaining strength profiles. The pressure meter uses a compressed gas to displace a fluid into a cylindrical probe installed in a hole, causing a uniform radial pressure to be applied to the hole wall over the depth of the probe. While the pressure meter yielded useful results, it was not strong enough for ice testing since it had been developed for soil testing, a material with ultimate strengths of the order of one tenth those of ice. Subsequently, a Goodman Jack was obtained from Slope Indicator of Seattle. It used hydraulic oil from a high pressure pump and pistons to push opposing rectangular plates against the wall of a drilled hole. It was strong (operating pressure internally of 70 MPa) but, because it had been developed for stiff rock testing, it did not have sufficient displacement to develop the ultimate strength of ice.
Year: 1992