by Van der Schrieck
Understanding the world of sand and water
The book is derived from chapters 4.1, 4.3 and 4.4 of the main book "Dredging Technology Book 1". It gives an overview of the physical behaviour of sand, clay and rock during cutting. Also formula’s to estimate and calculate cutting forces are being described. The phenomena “Dilatancy” an “Cavitation” inside a cut sand layer are being discussed together with their great impact on mixture formation.
The large effect of the rate of distortion on the specific energy when cutting Clay is explained. Several Rock failure modes are being described, depending not only on the ratio between the compressive strength and tensile strength of the rock but also on the actual level of the confining pressure inside the rock.
A description is given of the extremely high crack-tip velocity causing cavitation inside these cracks. It is explained why this phenomenon causes a mayor increase of the Rock cutting force and thus of the specific energy consumption when cutting at large water depths. This is still a problem in Deep Ocean mining.