LAUFZEITMESSUNGEN AN BOHRKERNEN UND GESTEINSPROBEN MIT ELEKTRONISCHEN MITTELN*

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Abstract
Supersonic pulses are transmitted into rock samples and cylindrical drill cores of about 10 cm to about 100 cm in length by a magnetostrictive driver attached to one end. The pulses are received at any chosen distance along the core by a small crystal geophone resting on the specimen. The beginning of the supersonic pulse and the wave form of the received disturbance, together with the marks of an accurate timer by a quartz clock, are made visual and stationary on the screen of a cathode‐ray oscillograph and the travel‐time is measured. Thus the core is picked up at different distances and a travel‐time curve is drawn from which the velocity of the waves is determined.The method is interpreted and the measuring device described. Graphs give several travel‐time curves of different rock samples, drill cores, metal rods and rods of other solid materials. The elastic moduli E of the samples are communicated, and an example is given for determining Poisson's ratio S from longitudinal and transversal velocities on two cores of sandstone.

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