. The elements of railroad engineering . I r^ I Fig. 395. Fig. 306. RAILROAD CONSTRUCTION. 899 railroad embankment where the back filling is subjected tothe constant vibrations caused by passing trains, its ultimatefailure is almost certain. A full proportion of large stones should show on bothfront and back and extend well into the wall, binding thewall compactly together, as shown in Fig. 396. RETAINING W^ALLS. 1480. A retaining -wall is one for sustaining thepressure of earth, sand, rock, or any other substancedeposited behind it after it is built. The material depositedis called filling or
. The elements of railroad engineering . I r^ I Fig. 395. Fig. 306. RAILROAD CONSTRUCTION. 899 railroad embankment where the back filling is subjected tothe constant vibrations caused by passing trains, its ultimatefailure is almost certain. A full proportion of large stones should show on bothfront and back and extend well into the wall, binding thewall compactly together, as shown in Fig. 396. RETAINING W^ALLS. 1480. A retaining -wall is one for sustaining thepressure of earth, sand, rock, or any other substancedeposited behind it after it is built. The material depositedis called filling or backing. Retaining walls are muchused in railroad construction, especially in sections wherethe natural slope of the ground approaches closely to that. Fig. 397. of the angle of ordinary earth filling, viz., 1^ horizontal to1 vertical. Railway tracks entering towns, especially wherethey cross or crowd other lines, terminal grounds, etc.,invariably require retaining walls. The pressure exertedby the backing will vary greatly, depending upon the slopeof the ground behind the wall, the nature of the materialcomposing the backing, and the manner of depositing it; butchiefly depending upon the height of the backing. Theusual form of retaining wall is shown in Fig. 397. There is 900 RAILROAD CONSTRUCTION. no invariable rule for determining the dimensions of retain-ing walls, and the rules of various authors differ following rule by Trautwine is based upon carefulexperiments and is widely adopted. The back of thewall is vertical, and the foundations not more than 3 Rule.— When the backing is elepositedloosely, being dumpedfrom earts, barrozcs, etc., ivall of e lit stone or first-e lass largeranged nibble in mortar, bas
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
