05.06.2013 Views

\fdO'^ - Old Forge Coal Mines

\fdO'^ - Old Forge Coal Mines

\fdO'^ - Old Forge Coal Mines

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

286 RAILROAD CONSTRUCTION.<br />

(859) First £^raviijf, i.e.,<br />

the weight of the wall itself,<br />

and second friction produced<br />

by the weight of the wall upon<br />

its foundation and by the<br />

pressure of the backing<br />

against the wall.<br />

(860) The angle of wall<br />

friction is the angle at which<br />

a plane of masonry must be<br />

inclined in order that dry<br />

sand and earth may slide<br />

freely<br />

over it.<br />

(861) The base ^/, Fig.<br />

74, of the triangle b d f is<br />

12.73 feet, and the altitude<br />

^ ^ is 16 feet. Hence, area of<br />

b d f is 12.73 X 8 = 101.84<br />

square feet. Taking the<br />

weight of the backing at 120<br />

pounds per cubic foot, we have<br />

the weight of bdf^ 101.84 X

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!