Part 15
===+===========+=======+==============+====+============+==+==+===+===+==| | | | AVE. NO. | W| | | OF MEN | e| | DESCRIPTION | IN GANG | i| |-------+--------------+----+------------+--+--+---+---+--| g| | | |Ave.| | | | | | | h| | | |air | | | | | | | t| | | | | | | | | A | | | | | |P | | | D| G | i | | o| | | |r | | | r| r | r | | f| | | |e | | S| i| o | | | | | | |s | | h| l| u | T |T | i| | | |s | | i| l| t | r |o | r| Section | | |u | | e| i| i | a |t | o| between |Length | |r |Method of | l| n| n | n |a | n| rings |in feet| Material |e |Excavation | d| g| g | s |l | ---+-----------+-------+--------------+----+------------+--+--+---+---+--| {| 28-42 | 37.5|Rock |12 |[B]Breast |13| 4| 1| 1 |19| O {| 43-58 | 40.0|Rock & gravel |12 | " |19| 2| 2| 2 |25| r {| 59-153 | 237.5|Gravel & sand |16 | " |25| | 1| 4 |30| d {| 154-170 | 42.5|Sand or silt, |18 | " |26| | 1| 5 |32| i {| | | with piles | | | | | | | | n {| 171-236 | 165.0|silt w/ piles |22 | " |22| | 1| 3 |26| a {| 237-259 | 57.5|Silt |25 |[C]1 door |18| | 1| 3 |22| r {| 260-625 | 915.0| " |27 | 1 " |18| | | 4 |22| y {|-----------+-------+--------------+----+------------+--+--+---+---+--| {| 28-625 |1,495.0| |25 | |19|.8|0.8|3.4|24| ---+-----------+-------+--------------+----+------------+--+--+---+---+--| Hvy| 626-1,312|1,717.5|Silt |28 | |25| | | 8 |33| ---+-----------+-------+--------------+----+------------+--+--+---+---+--| All| 28-1,312|3,212.5| |26 | |21| | | 5 |26| ===+===========+=======+==============+====+============+==+==+===+===+==|
TABLE 27 SUMMARY PART 2
===+========+========+=======+======+====+=====+===============+========| W | | | | UNAVOIDABLE DELAYS | e | | | AVERAGE TIME |(NOT INCLUDED IN AVERAGE| i o| | | PER RING. | TIME PER RING). | g f| | |-------+------+----+-----+---------------+--------| h |Average | Time | | | | | | | t i| No. of |mucking,|Shoving| | | | | | r| cubic | per | and | Erec-| | | | | o| yards | cubic |mucking| tion |Lost| | | Time | n|per ring| yard | [Z] | [A] |time|Total| Items |hrs min| ---+--------+--------+-------+------+----+-----+---------------+--------| {| 48.7 | 0-25 | 20-33 | 4-21|0-12|25-06|First bulkhead | 80-00| O {| 44.2 | 0-46 | 33-44 | 4-44|1-15|39-43|Second bulkhead| 156-00| r {| 39.0 | 0-12 | 8-06 | 2-23|0-30|10-59|Grouting rock | 280-00| d {| 41.6 | 0-10 | 7-10 | 1-59|0-0 | 9-09| sections| | i {| | | | | | |Blow-outs | 222-00| n {| 42.6 | 0-10 | 7-23 | 2-35|0-05|10-03|Shield repairs | 326-40| a {| 13.8 | 0-11 | 2-29 | 2-32|0-20| 5-21|Horz. timbers | 69-30| r {| 3.6 | 0-06 | 0-40 | 2-39|0-14| 3-33| Total |1,134-10| y {|--------+--------+-------+------+----+-----+---------------+--------| {| 17.8 | 0-14 | 4-14 | 2-41|0-16| 7-11|Per ring | 0-53| ---+--------+--------+-------+------+----+-----+---------------+--------| Hvy| 10.6 | 0-4 | 0-56 | 1-57|0-16| 3-09| | | ---+--------+--------+-------+------+----+-----+---------------+--------| All| 14.1 | 0-10 | 2-28 | 2-18|0-15| 5-01| | | ===+========+========+=======+======+====+=====+===============+========|
[Z] Including time for jacks.
[A] Including bolting time.
[B] Excavating ahead of shield.
[C] Shoving shield into silt with ... doors open.
The average time taken for each operation at all the working faces is given in Table 28. The work has been subdivided into the different kinds of ground encountered.
The progress, as shown by the amount of work done each month by each shield, is given in Table 29.
TABLE 28.--SHIELD-DRIVEN TUNNEL WORK.--TOTAL NUMBER OF RINGS ERECTED AND SHIFTS WORKED BY ALL FOUR SHIELDS IN CONTRACTS GY-WEST AND GJ, AND THE AVERAGE SIZE OF GANG, AMOUNT OF EXCAVATION AND TIME TAKEN PER RING FOR THE VARIOUS OPERATIONS INVOLVED IN BUILDING TUNNEL IN EACH OF THE SEVERAL KINDS OF GROUND ENCOUNTERED; ALSO THE EXTENT AND NATURE OF ALL THE UNAVOIDABLE DELAYS.
TABLE 28 PART 1
===+===================+=====+========+======+==+====+====+====+====+====| | | | | |A | AVE. NO. | W| | | | |v | OF MEN | e| | | | | | IN GANG | i| | | | |a +----+----+----+----+----+ g| | | | |i | | | | A | | h| | | | |r | | D | G | i | | t| | | |Total | | | r | r | r | | | | | | |p | S | i | o | | | o| |Total| Total |number|r | h | l | u | t | T | f| | | | |e | i | l | t | r | o | | Description | No. | No. | of |s | e | i | i | a | t | i| | | | |s | l | n | n | n | a | r| of | of | of |8-hour|u | d | g | g | s | l | o| | | | |r |----+----+----+----+----+ n| Material |rings| feet. |shifts|e |Unit|Unit|Unit|Unit|Unit| ---+-------------------+-----+--------+------+--+----+----+----+----+----+ {|Rock. | 165| 412.5| 597 |16| 18 | 9 |0.25| 1 | 28 | O {|Rock and earth and | 177| 442.5| 500 |14| 22 | 5 |0.3 | 2 | 30 | r {| rock and gravel.| | | | | | | | | | d {|Sand and gravel | 188| 470.0| 241 |13| 24 | |0.6 | 3 | 27 | i {| (unobstructed), NJ| | | | | | | | | | n {|Sand and silt (with| 171| 427.5| 199 |22| 23 | |1.0 | 3 | 27 | a {| piles.)| | | | | | | | | | r {|Silt under R. R. | 396| 990.0| 355 |19| 27 | | | 3 | 30 | y {| tracks, NY| | | | | | | | | | {|Rip-rap and silt | 77| 192.5| 193 |23| 26 | | | 4 | 30 | | under bulkhead.| | | | | | | | | | i {| |-----+--------+------+--+----+----+----+----+----| r {|Total mixed and | | | | | | | | | | o {| difficult ground.|1,174| 2,935.0|2,085 |17| 22 | 4 |0.3 | 3 | 29 | n {|-------------------+-----+--------+------+--+----+----+----+----+----+ {|Silt--ordinary iron|1,302| 3,255.0| 676 |25| 22 | | | 4 | 26 | ---+-------------------+-----+--------+------+--+----+----+----+----+----+ Hvy|Silt--heavy iron. |2,209| 5,522.5| 791 |26| 25 | | | 8 | 33 | ---+-------------------+-----+--------+------+--+----+----+----+----+----+ |Silt--ord and heavy| | | | | | | | | | |iron under river. |3,511| 8,777.5|1,467 |26| 24 | | | 6 | 30 | |-------------------+-----+--------+------+--+----+----+----+----+----+ |Grand total. |4,685|11,712.5|3,552 |21| 23 | 2 |0.2 | 4 | 29 | ===+===================+=====+========+======+==+====+====+====+====+====|
TABLE 28 PART 2
====+====+=======+========+=======+=======+=============+========| | | | | | | | | | | | | | | | | | | | | | | | AVE. UNAVOIDABLE | | | | DELAY PER | | | AVERAGE TIME PER RING. | WORKING FACE. | Cu. |Time|------------------------+-------+-------------+--------| yd. |per |Shoving| | | | | Time | per |cu. | and | | Lost | | Items |--------| ring|yd. |mucking|Erecting| time | Total |not included |Ave unit| ----+----+-------+--------+-------+-------| in previous |--------| Unit|Unit|Hrs Min|Hrs Min |Hrs Min|Hrs Min| figures |Hrs Min | | | K | L | M | | | | ----+----+-------+--------+-------+-------+-------------+--------| 51 |0-27| 25 15| 3 41 | 0 02| 28 58|1st Bulkhead |136 00 | 45 |0-26| 19 31| 2 55 | 0 11| 22 37| 2d " |147 54 | | | | | | | | | 39 |0-12| 7 31| 2 24 | 0 20| 10 15|Grouting |246 00 | | | | | | | | | 43 |0-09| 6 46| 2 24 | 0 09| 9 19|Blow-outs | 91 11 | | | | | | | | | 42 |0-06| 4 09| 2 51 | 0 10| 7 10|Miscellaneous|230 33 | | | | | | | | | 43 |0-21| 14 47| 3 41 | 1 34| 20 02|Total |851 38 | | | | | | | | | ----+----+-------+--------+-------+-------+-------------+--------| | | | | | | | | 43 |0-18| 11 02| 2 54 | 0 16| 14 12| | | ----+----+-------+--------+-------+-------+-------------+--------| 12 |0-07| 1 20| 2 35 | 0 14| 4 12| | | ----+----+-------+--------+-------+-------+-------------+--------| 12 |0-05| 0 58| 1 44 | 0 10| 2 52| | | ----+----+-------+--------+-------+-------+-------------+--------| | | | | | | | | 12 |0-06| 1 09| 2 05 | 0 12| 3 26| | | ----+----+-------+--------+-------+-------+-------------+--------| 20 |0-11| 3 33| 2 15 | 0 13| 6 01| | | ----+----+-------+--------+-------+-------+-------------+--------|
Average delay per ring--0 hrs. 44 min. Average rings built by one shield = 1,146¼.
Average time per ring. 6 hr 01 min Delays. 44 min ----------- Total time per ring. 6 hr 45 min
NOTE.--The "unavoidable delays" included in this table do not embrace the periods during which the work was at complete or partial standstill due to experiments and observations, shortage of iron due to change of design, and holidays.
K-Including time for jacks.
L-Including time spent by the whole gang on bolting; in addition to this there was a small gang which spent its whole time bolting.
M-Chiefly due to breakdowns of hydraulic lines and erector.
_Air Pressure._--The air pressure varied from 17 to 37 lb. Behind the river line it averaged 17 lb. and under the river 26 lb. Behind the river lines the pressure was generally kept about equal to the water head at the crown, except where at Weehawken, as previously described, this was impossible.
In the silt the pressure was much lower than the hydrostatic head at the crown, but if it became necessary to make an excavation ahead of the shield, for example at the junction of the shields, the air pressure required was about equal to the weight of the overlying material, namely, the water and the silt, as the silt, which weighed from 97 to 106 lb. per cu. ft. and averaged 100 lb. per cu. ft., acted like a fluid.
TABLE 29.--MONTHLY PROGRESS OF SHIELD-DRIVEN TUNNEL WORK.
=====+=============================+=============================+ | North Manhattan. | South Manhattan. | +-----------------------------+----------------------+------+ | Number of | Station |Lin. | Number of | Station |Lin. | | rings | of |ft. | rings | of |ft. | | erected. | leading |for | erected. | leading |for | +-----------+ ring. |month.+-----------+ ring. |month.| |For | To | | |For |To | | | Month|month|date | | |month|date | | | -----+-----+-----+----------+------+-----+-----+----------+------+ 1905 | | | | | | | | | May | 26 | 26|200 + 83.7| 63.7 | | | | | June | 26 | 52|201 + 49.0| 65.3 | | | | | July | 28 | 80|202 + 19.2| 70.2 | | | | | Aug | 26 | 106|202 + 84.3| 65.1 | | | | | Sept | 21 | 127|203 + 36.8| 52.5 | 31 | 31|200 + 96.4| 76.4 | Oct | 25 | 152|203 + 99.4| 63.6 | 45 | 76|202 + 09.2|112.8 | Nov | 31 | 183|204 + 76.9| 77.5 | 31 | 107|202 + 86.5| 77.3 | Dec | 59 | 242|206 + 24.6|147.7 | 34 | 141|208 + 71.8| 85.3 | 1906 | | | | | | | | | Jan | 94 | 336|208 + 59.8|235.2 | 27 | 168|304 + 39.4| 67.6 | Feb | 78 | 414|210 + 54.9|195.1 | 64 | 232|205 + 99.6|160.2 | Mar | 56 | 470|211 + 95.2|140.3 | 96 | 328|208 + 39.9|240.3 | April| 119 | 589|214 + 93.0|297.8 | 84 | 412|210 + 59.1|210.2 | May | 129 | 718|218 + 15.7|322.7 | 70 | 482|212 + 25.3|165.2 | June | 218 | 936|232 + 60.9|545.2 | 140 | 622|215 + 75.5|350.2 | July | 155 |1,091|227 + 48.5|387.6 | 82 | 704|217 + 80.7|205.2 | Aug | 145 |1,236|231 + 11.2|362.7 | 134 | 838|221 + 15.8|335.1 | Sept | 89 |1,325|233 + 34.1|222.9 | 168 |1,006|225 + 35.8|420.0 | Oct | | | | | 105 |1,111|227 + 98.6|262.8 | Nov | | | | | 7 |1,118|228 + 16.8| 18.2 | =====+=====+=====+==========+======+=====+=====+==========+======+
=====+=============================+============================+======== | North Weehawken. | South Weehawken. | +-----------------------------+----------------------------+Average | Number of | Station |Lin. | Number of | Station |Lin. |progress | rings | of |ft. | rings | of |ft. |per | erected. | leading |for | erected. | leading |for |shield +-----------+ ring. |month.+-----------+ ring. |month|lin. ft. |For | To | | |For |To | | |per Month|month|date | | |month|date | | |month. -----+-----+-----+----------+------+-----+-----+----------+-----+-------- 1905 | | | | | | | | | May | | | | | | | | | 15.9 June | 24 | 24|260 + 76.6| 59.3 | 12 | 12|260 + 70.0| 30.0| 38.6 July | 12 | 36|260 + 46.6| 30.0 | 15 | 27|260 + 32.4| 37.6| 34.4 Aug | 15 | 51|260 + 09.1| 37.5 | 16 | 43|260 + 07.4| 25.0| 31.9 Sept | 1 | 52|260 + 06.6| 2.5 | 18 | 61|259 + 47.2| 60.2| 47.9 Oct | 10 | 62|259 + 81.5| 25.1 | 20 | 81|258 + 97.2| 50.0| 62.9 Nov | 29 | 91|259 + 09.0| 72.5 | 39 | 120|257 + 99.7| 97.5| 81.2 Dec | 46 | 137|257 + 94.0|115.0 | 77 | 197|256 + 07.1|192.6| 135.1 1906 | | | | | | | | | Jan | 77 | 214|256 + 01.4|192.6 | 73 | 270|254 + 24.6|182.5| 169.4 Feb | 133 | 347|252 + 68.6|332.8 | 165 | 435|250 + 11.7|412.9| 275.2 Mar | 142 | 489|249 + 13.3|355.3 | 111 | 546|247 + 34.0|277.7| 253.4 April| 32 | 521|248 + 33.3| 80.0 | 78 | 624|245 + 38.9|195.1| 195.7 May | 121 | 642|245 + 30.6|302.7 | 2 | 626|245 + 33.9| 5.0| 198.9 June | 162 | 804|241 + 25.3|405.3 | 157 | 788|241 + 41.1|392.8| 423.4 July | 113 | 917|238 + 42.4|282.9 | 118 | 901|238 + 45.9|295.2| 292.7 Aug | 138 |1,055|234 + 97.1|345.3 | 140 |1,041|234 + 95.8|850.1| 348.3 Sept | 55 |1,110|233 + 59.5|137.6 | 177 |1,218|230 + 52.8|443.0| 305.9 Oct | 1 |1,111|233 + 57.0| 2.5 | 94 |1,312|228 + 16.8|236.0| 125.3 Nov | 9 |1,120|233 + 34.1| 22.9 | | | | | 10.3 -----+-----+-----+----------+------+-----+-----+----------+-----+--------
A ½-in. air line was taken direct from the working chamber to the recording gauges in the engine-room, which enabled the engine-room force to keep a constant watch on the air conditions below. To avoid undue rise of pressure, a safety valve was set on the air line at each lock, set to blow off if the air pressure rose above that desired. The compressor plant was ample, except, as before described, when passing the gravel section at Weehawken.
Records were kept of the air supply, and it may be said here that the quantity of free air per man per hour was in general between 1,500 and 5,000 cu. ft., though in the open gravel where the escape was great it was for a time as much as 10,000 cu. ft. For more than half the silt period it was kept between 3,000 and 4,000 cu. ft., but when it seemed proved beyond doubt that any quantity more than 2,000 cu. ft. had no beneficial effect on health, no attempt was made to deliver more, and on two separate occasions for two consecutive weeks it ran as low as 1,000 cu. ft. without any increase in the number of cases of bends.
The amount of CO_{2} in the air was also measured daily, as the specifications called for not more than 1 part of CO_{2} per 1,000 parts of air. The average ranged between 0.8 and 1.5 parts per 1,000, though in exceptional cases it fell as low as 0.3 and rose to 4.0. The air temperature in the tunnels usually ranged from 55° to 60° Fahr., which was the temperature also of the surrounding silt, though at times, in the earlier parts of the work when grouting extensively in long sections of the tunnel in rock, it varied from 85° to 110° Fahr.
_Grouting._--Grout of one part of Portland cement to one part of sand by volume was forced outside the tunnel lining by air pressure through 1½-in. tapped and plugged grout holes formed in each segment for this purpose, wherever the ground was not likely to squeeze in upon the metal lining as soon as this was erected. That is to say, it was used everywhere up to the river line; between river lines it was not used except at the New York bulkhead wall in order to fill voids in the rip-rap, and at the point of junction of the shields where the space between the metal lining and the shield skins outside it was grouted. Cow Bay sand was used, and it had to be screened to remove particles greater than 1/10 in. in diameter, which would choke the valves. For later grouting work, namely, in the top of the concrete lining inside the metal lining, Rockaway Beach sand was used. This is very fine, and did not need screening; it cost more, but the saving of screening and the non-blocking of valves, etc., resulted in a saving.
The grout was mixed in a machine shown in Fig. 2, Plate XLI, which is a view of the grouting operation.
The grout pipes were not screwed directly into the tapped hole in the segments, but a pipe containing a nipple and valve was screwed into the grout hole and the grout pipe screwed to the pipe. This prevented the waste of grout, enabled the valve to be closed and the grout pipe disconnected, and the pipe to be left in position until the grout had set. In the full rock section, 20 or 30 rings were put in without grouting; then the shield was stopped, the last two or three rings were detached and pulled ahead by the shield, a masonry stop-wall was built around the outside of the last ring left in, and the whole 20 or 30 rings were grouted at one time. In the landward silt and gravel each ring had to be grouted as soon as the shield had left it, in order to avoid the flattening caused by the weight coming on the crown while the sides were as yet unsupported. The grout was prevented from reaching the tail of the shield by plugging up the space with empty cement bags, assisted by segmental boards held against the face of the leading ring by U-shaped clamps, fitting over the front circumferential flange of the ring and the boards, and tightened by wedges. The air pressure varied between 70 and 100 lb. per sq. in. above normal.
The force consisted of one pipe-fitter and one or two laborers employed part of their time. When a considerable length was being grouted at a time, as in the full rock section, many laborers were employed for a short period.
Transportation and Disposal.
The transportation and disposal will be described under the following headings:
Receipt and Unloading of Materials, Surface Transportation, Tunnel Transportation, Disposal.
_Receipt and Unloading of Materials._--At the Manhattan Shaft the contractor laid a spur siding into the yard from the freight tracks of the New York Central Railroad, which immediately adjoins the yard on the west. There was also wharfage on the river front about 1,500 ft. away.
At the Weehawken Shaft there were four sidings from the Erie Railroad and one from the West Shore Railroad. Access to the river was gained by a trestle direct from the yard, and Baldwin Avenue adjoined the yard.
All the iron lining arrived by railroad. It was unloaded by derricks, and stacked so that it was convenient for use in the tunnel. The Manhattan derricks were a pair of steel ones with 39-ft. booms, worked by a 30-h.p., 250-volt, electric motor. There was also a stiff-leg derrick with 50-ft. boom, on a platform near the shaft, which was worked by a 40-h.p., 250-volt motor. At Weehawken there were two 45-ft. boom, stiff-leg derricks of 2 tons capacity, one worked by a 42-h.p. Lidgerwood boiler and engine, and the other by a 25-h.p., 250-volt, electric motor. These derricks were set on elevated trestles near the Erie Railroad sidings. There was a 50-ft. stiff-leg derrick with a 70-h.p. Lidgerwood boiler and engine near the cement warehouse on the West Shore Railroad.
The storage area for iron lining was 1,800 sq. ft. at Manhattan and 63,000 sq. ft. at Weehawken; the maximum quantity of lining in storage at any one time was 150 rings at Manhattan and 1,200 rings at Weehawken.
The cement, which was issued and sold by the Company to the contractor, was kept in cement warehouses; that at the New York side was at Eleventh Avenue and 38th Street, or some 1,200 ft. from the shaft, to which it was brought by team; that at Weehawken was adjacent to the shaft, with a 2-ft. gauge track throughout it and directly connected with the shaft elevator.
_Surface Transportation._--In the early days the excavation was handled in scale-boxes of 1 cu. yd. capacity which were hoisted up the shafts by a derrick, but, when the iron period began, two-cage elevators were put in at each shaft. They were worked by a single, friction-drum, Lidgerwood, steam hoisting engine of 40 h.p.