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

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

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16.2.9. Calc.: Bulldozer 2.<br />

<strong>The</strong> <strong>Delft</strong> <strong>Sand</strong>, <strong>Clay</strong> & <strong>Rock</strong> <strong>Cutting</strong> <strong>Model</strong>.<br />

A bulldozer with a blade height of 1.0 m and a blade angle of 90 degrees is pushing dry sand. <strong>The</strong> internal<br />

friction angle of the sand is 45 degrees. <strong>The</strong> sand has no cohesion or adhesion and the friction between the<br />

sand and the blade is assumed to be zero, so a smooth blade. <strong>The</strong> bulldozer has a maximum forward speed<br />

of 1.0 m/sec. <strong>The</strong> bulldozer has a maximum pushing force of 100 kN.<br />

1. What is the coefficient of passive failure for this sand?<br />

<br />

<br />

1 sin 1 sin /4<br />

Kp<br />

5.826<br />

1 sin 1 sin /4<br />

<br />

<br />

<br />

<br />

(-)<br />

2. What is the maximum width of the bulldozer blade?<br />

<strong>The</strong> density of the dry sand ρs with 40% porosity is about 1.6 ton/m 3 .<br />

1<br />

2<br />

F s g h w Kp<br />

100 kN<br />

2<br />

100 100<br />

w= <br />

2.187 m<br />

1 2<br />

2<br />

<br />

0.5 1.6 9.81 1 5.826<br />

s g h K<br />

<br />

p<br />

2<br />

Page 404 of 454 TOC Copyright © Dr.ir. S.A. Miedema

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