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The Delft Sand, Clay & Rock Cutting Model, 2019a

The Delft Sand, Clay & Rock Cutting Model, 2019a

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A Wedge in Atmospheric <strong>Rock</strong> <strong>Cutting</strong>.<br />

Figure 14-4: <strong>The</strong> forces on the blade when a wedge is present.<br />

14.3. <strong>The</strong> Equilibrium of Moments.<br />

In order to solve the problem, also the equilibrium of moments is required, since the wedge is not subject to<br />

rotational acceleration. <strong>The</strong> equilibrium of moments can be taken around each point of the wedge. Here the tip of<br />

the blade is chosen. <strong>The</strong> advantage of this is that a number of forces do not contribute to the moments on the<br />

wedge.<br />

Figure 14-5: <strong>The</strong> moments on the wedge.<br />

In order to derive the equilibrium of moments equation the arms of all the forces contributing to this equilibrium<br />

have to be known. Since these arms depend on the length of all the sides in the cutting process, first these lengths<br />

are determined. <strong>The</strong> length of the shear plane A-B is:<br />

L<br />

1<br />

h<br />

<br />

sin<br />

i<br />

<br />

(14-19)<br />

Copyright © Dr.ir. S.A. Miedema TOC Page 389 of 454

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