102 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Deoemeer, 



•' Sept. 12.— Mr. Bush again reported that he, accnmpanied by Lieu- 

 tenant Batt, R.N., in Her Majesty's cutter Sealarlc, matle a minute 

 siuvey of the caisson after the gale, (of the Gtb instant,) and found 

 that It had not tlie slightest effect upon it, and tliat it remained quite 

 perpendicular alter having been subjeoled for many liours to the 

 violence of the storm." 



A small stage was washed oti', which was not of any importance 

 whatever; and the spar aud derrick. The part shown by the dotted 

 line was also broken away. 



Fig. 2.— Section of Caisson. 



ll ci f ^Hi^fffCaissoon 



By a reference to our description in the Journal for October last, 

 the annexed engraving, Fig. 2, will explain the construction of the 

 iron caisson. 



NOTES ON EARTH WORK, EXCAVATION, CUTTING, AND FORMING 

 EMBANKMENT UPON RAILWAYS. 



Article III. — Extent, Form, and Proportions. 



" Modern practice has reduced it to a price per cubic yard." 



Professor Figjiolcs' Lecture. Dec. ISil. 



In my two previous communications (see pages 84 and 18G of the present 

 volume,) I have endeavoured to show what is tlic price of earth work, taking 

 ordinary soil as the standard, and then stated the price of excavation to be 

 4id., and of forming embankment under one mile in length to be 12d. and 

 3d. extra per additional mile ; and taking the average length to which earth 

 has been led, I find earthwork to liave cost on the following lines, Midland 

 Counties, 13</., Derby and Birmingham, 12\d., Great Western, 12d., and North 

 Union, lOJrf. I have aho stated, at page 186, the extent to which it is pru- 

 dent to employ horse power to be 2i miles, and even when there is a steam 

 liorse, as the locomotive was once named, it is not prudent to carry earth more 

 than 4 miles. I now propose to consider whether it be not more economical 

 to run excavation to spoil where it is got, and purchase earth on the spot 

 where it is wanted, aud for embankment to get it from a side cutting out of 

 the hne of railway. At [lagc 84 of t!ie present volume I have given a 

 table oi" the cost of back cutting or earth excavation from or in the hne of 

 intended railway. I now, fur the sake of comparison, give a similar table of 

 the cost of side cutting. 



The side cutting was of similar material to the cutting in line of railway 

 forajerly described, and was made from an angular severance; the length of 

 the side of the triangle next the line was about 'JO chains long, and the em- 

 bankment formed w;:.s about 12 ft. in length, about 12,000 cubic yards were 

 moved without the aid of rails, by barrows only ; the total quantity being 

 aiiout 40,000 yards; out of 20,000 yards that were moved, 18,000 were got 

 within 20 yards of the edge of the raiiwjy, fiOOO within 35 yards, and 2000 

 heyond 35 yards. The contractor was paid per cubic yard Od. within 20 

 yariJs, 'id. witl.in .j.') yards, and 8ld for all beyond that distance. .\s a 

 security for the performance of the contract, one penny per cubic yard was 

 retained out of his payments, until half the quantity was performed, and he 

 was paid Id. per cubic yard extra for ballast, *hich was raised from the 



bottom with horse runs. By a comparison with the price paid for the former 

 cutting, it will be seen that no great difference exists as to price, neither as 

 to the expedition of the one process over the other. ' The preceding and fol- 

 lowing tables were obtained by a close attention and personal superintend- 

 ence of several months, and at an expense that few contractors would go to. 

 The number of wagons were counted by the sub-contractor at the face of the 

 work, and by a person at the tip on the part of the employer ; in one case 

 the sub-contractor had bribed the counter to make a false return of the num- 

 ber, but as he was not content with a small defection, it was found out on 

 the second day. Had it been otherwise, the defalcation wouUl have been 

 difficult of detection, as from natural causes, weather, lost time, difference 

 of the earth's tenacity, the number of yards excavated by each man etiiploycd, 

 varying as much as cent per cent. 



Table of Cost of Excavation frou Sidk Cutting. 



No. of No. of Wagons No. of Wagons Cubic yds. 



1837 days' work, of 2 J c. yds. of lie. yds. per man. 



March 11 '208 40 1452 8J5j 



18 248 84 1150 8 nearly. 



25 358 243 1302 7^% 



April 1 376 338 1324 C full. 



8 312 213 1251 8 nearly. 



Table ok tke ncmbf.r of Men to number of Wagons. 



No. of Wagons of 

 li c. yd. each. 

 185 

 275 

 » 294 

 216 

 133 

 190 

 201 

 138 

 239 

 406 

 447 

 201 

 246 

 138 

 133 

 203 

 181 

 192 

 754 

 744 

 400 



By comparing the above table with the former tables, it will be found 

 that side cutting is a small fraction cheaper, but the extra quantity of ma- 

 terials and consequent expense will make the two processes equal or 

 nearly so. 



Now that the excavation is to be executed at both ends, it will cost only 

 9(/., and having previously stated four miles as the distance or extent to 

 which it is prudent earth should be transported, the cost of which is esti- 

 mated at Is. 9d. by the scale of leadage i have the difference of 1«. 

 to play upon. Let us suppose that the laud for side cutting is entirety 

 destroyed, and that it was purchased at the rate of 70/. per acre, and that trie 

 excavation could be got down feet over the whole surface without having 

 to contend with water, which would be as much as conld be done, the lo- 

 cahty of embankna-nt being valley, often abounding in water ; under the 

 above circumstances, the earth would cost excavating id, per cubic yard, at 

 the side cutting end, and if the value of the land at the spoil end be calcu- 

 lated at half the purchase price, which is only injured, not destroyed, it will 

 cost 2d. per cubic yard more, making, with the cost of excavating, 6d., 

 which will leave 6d. ; this will pay for carrying the earth 2 miles further 

 than first estimated, hence six miles will be the horizontal extent to which 

 earth work can be removed with prudence, or the point where back cuttings, 

 with a leadage of 4 miles, and siile cutting with a leadage of miles, will 

 cost equal or Is. Or/, per cubic yard. 



Having disposed of the horizontal extent to which earthwork may be re- 

 moveil, I will now consider the transverse extent, and the comparison of 

 the cost at one end of oi)en cutting with tunnel, and at the other end em- 

 bankment with viaihict ; I will first then proceed to show where the cost of 



' The Table in the last March No., p. 85, col. 2, hne 26, should be, 

 " the fourth the cubic yards moved per man," instead of " the fourth the 

 price per cubic yard." 



