Part 12
The iron was brought into the tunnel on flat cars, two segments to the car, and was lifted from the car and lowered into the invert of the shield by a block and fall and chain sling, as shown in Fig. 2, Plate XXXIX. The bottom three or four segments were pushed around into position with the erector, the head simply bearing against the longitudinal flange without being attached to the segment; the upper segments, however, were, as shown in Fig. 2, Plate XXXVIII, and Fig. 1, Plate XLI, attached to the erector, by using the expanding bar and the erector head designed by Mr. Patrick Fitzgerald, the Tunnel Superintendent. This was found to be a most convenient arrangement.
The single erector attached to the center of the shield was able to erect the iron as fast as it could be brought into the tunnel, and even when the weight of the segments was increased 25% (from 2,060 to 2,580 lb.) it always proved equal to its task, although occasionally one of the chains in the mechanism broke and delayed the work for an hour or so; but the sum of all the delays from this cause and from breaks and leaks in the hydraulic line only averaged 13 min. per ring. The operating valve which was first used was a four-spindle turning valve, but this was replaced by a sliding valve which was found to be much more satisfactory, both in ease of operation and freedom from failure.
As the iron was put into place, two of the middle bolts in each longitudinal flange and two in each circumferential one were pulled as tight as possible, and the others put in loosely; then, as soon as the ring was in position, as large a force as could be conveniently worked at one time was engaged in tightening the bolts. The shape of the tunnel depended on the thoroughness of the tightening of the bolts, and the shield was never shoved until the bolts in all the longitudinal flanges had been thoroughly tightened. In addition, all the bolts in the circumferential flanges below the axis were tightened, and at least three of the six in each segment above. After the shield had been shoved ahead, the bolts were found to have slackened, and, where the daily progress was four rings, or more, it was necessary to have a small gang of men always at this work.
In order to get at the bolts, special platforms were necessary, and throughout the greater part of the work, a traveling platform was used. This enabled the men to reach handily all parts of the seven leading rings. This platform was supported and moved forward on wheels fixed on brackets to the tunnel, and was pulled forward by connecting chains every time the shield was shoved. In the early part of the work it was not possible to use platforms, because, in order to maintain the correct circular shape of the iron lining, it was necessary to put in temporary horizontal turnbuckles at axis level. These, however, were very convenient for supporting the planks which were used as a temporary bolting platform for the sides of the tunnel, and a temporary platform resting on 6 by 6-in. timbers across the tunnel enabled the bolts in the crown of the tunnel to be reached, while the 6 by 6-in. timbers were left in to support the emergency platform previously described (Plate XL), which extended the entire length of the tunnel.
The time taken to erect the iron lining became shorter and shorter as the tunnel organization became more perfect and the force better trained, so that, whereas, in the early part of the work, it frequently took 6 hours to erect a ring, in the latter part, when the work was nearing completion, it was a common occurrence to erect a ring in 30 min. The average time in the "heavy iron" section, which included the greater part of the work under the river, was 1 hour 4 min. for the erection of the ring and 40 min. for tightening the bolts after that had been completed, so that the total time spent by the whole gang on erection and bolting averaged 1 hour 44 min. per ring, exclusive of the time spent by the small gang which was always engaged in tightening the bolts. The average time spent in erecting and bolting, for the whole length of the tube tunnels, was 2 hours 15 min. per ring.
_Tables of Progress._--Tables 24, 25, 26, and 27 have been prepared to show the time taken in the various operations at each working face.
In Tables 24, 25, 26, and 27, the following symbols are used:
_A_--Including assistant superintendents, foremen, and electricians, in driving the shield, erecting iron, mucking, attending to the electric lights, and repairing the pipe line.
_B_--Drillers, drillers' helpers, drill foremen, and nippers.
_C_--All men grouting.
_D_--Engineers and laborers wholly employed on transport between the first lock and the face.
_E_--In rock, one car = 0.60 cu. yd.; in sand or silt = 1.20 cu. yd. in place.
_F_--Time between completion of mucking and putting in first plate, spent in shoving the jacks back.
_G_--In ordinary iron = the whole time spent on erection and bolting. In heavy iron = the time between putting in the first plate and placing the key only.
_H_--Time between placing the key and starting the next shove, spent by the whole gang in tightening bolts. In addition to this, there was a small gang which spent its whole time at this work.
_I_--In Table 24 the first pair of bore segments is at ring 207-208. " " 25 " " " " " " " " " 201-202. " " 26 " " " " " " " " " 185-186. " " 27 " " " " " " " " " 171-172.
Outside diameter of tunnel = 23 ft. 0 in. Inside " " " = 21 ft. 2 in. Length of ring = 2 ft. 6 in.
In the "Ordinary Iron" section the time is divided between mucking (which included the shoving and pushing back of the jacks) and the erection time (which included the time spent by the whole gang in tightening bolts). In the "Heavy Iron" section these times are all separated into "Mucking," "Pushing Back Jacks," "Erecting," and "Bolting," and here the bolting time included only that spent on bolts by the whole gang; in addition, there was a small gang engaged solely in tightening bolts. The lost time is the average time lost due to the break-down of hydraulic pipe lines, damaged jacks, and broken erector chains. The erection time is separated for the various kinds of rings, that is, straight ordinary rings, rings containing No. 1 bore segments, rings containing No. 2 bore segments, and taper rings, and it will be seen that, on the average, taper rings took 22 min. (or 24%) more time to erect and to bolt than ordinary ones, and that rings containing No. 2 bore segments took 14 min. (or 15%) more.
TABLE 24.--SHIELD-DRIVEN TUNNEL WORK, MANHATTAN SHAFT, RIVER TUNNEL NORTH. Table showing the size of the gang, the amount of excavation, and the time per ring taken for the various operations involved in building tunnel through the several kinds of ground encountered; also the extent and nature of all the unavoidable delays.
TABLE 24 PART 1
=+===========+=======+=============+===+=============+=====+===+==+==| W| | | AVE. NO. | e| | | OF MEN | i| | DESCRIPTION | IN GANG | g| |-------+-------------+---+-------------+--+--+---+--+--| h| | | |Ave| | | | |A | | t| | | |air| | |D |G |i | | | | | | | | |r |r |r | | o| | | |P | |S |i |o | | | f| | | |r | |h |l |u |t |T | | | | |e | |i |l |t |r |o | | | | |s | |e |i |i |a |t | i| | | |s | |l |n |n |n |a | r| Section | | |u | |d |g |g |s |l | o| between | Length| |r |Method of |--+--+---+--| | n| rings |in feet|Material |e |Excavation |A |B |C |D | | -+-----------+-------+-------------+---|-------------+--+--+---+--+--| | 1-54 | 135.0|Rock | |[P] | | | | |14| | 55-80 | 65.0| " |19 |[P] |24| 7|1/3| 1|32| | 81-107 | 65.0|Soft rock |18 |[P] |22| 5| | 2|29| O| 108-153 | 117.5|Rock |14 |[P] |17|11| | 2|30| r| 154-194 | 102.5|Rock and |14 |[P] |23| 6| | 2|31| d| | |earth | | | | | | | i| 195-215 | 52.5|Silt |19 |[P]Breasting |28| | | 2|30| n| 216-393 | 445.0| " |20 |[Q]8 doors |27| | | 4|31| a| 394-429 | 90.0|Silt, piles, |24 |[C]Breasting |28| | | 4|32| r| | |rip-rap | | | | | | | y| 430-509 | 200.0|Silt |23 |[Q]1 door |24| | | 3|27| | 510-692 | 457.5| " |23 |[Q]3 doors |26| | | 4|30| | 55-692 |1,593.0| |20 | |25| 2| | 3|30| | 216-692 |1,192.5| |22 | |26| | | 4|30| -+-----------+-------+-------------+---+-------------+--+--+---+--+--| | 693-954 | 655.0|Silt |24 |[Q]1 door |28| | | 6|34| | 955-1,014 | 150.0| " |24 |[Q]1 " |28| | | 8|36| |1,015-1,074| 150.0| " |24 |[Q]1 " |25| | | 8|33| H|1,075-1,134| 150.0| " |24 |[Q]1 " |27| | | 9|36| e|1,135-1,194| 150.0| " |25 |[Q]1 " |26| | | 8|34| a|1,195-1,224| 75.0| " |25 |[Q]1 " |24| | | 9|33| v|1,225-1,262| 95.0| " |25 |[Q]1 " |23| | | 9|32| y|1,263-1,277| 37.5| " |25 |[Q]1 " |24| | |10|34| |1,278-1,307| 75.0| " |25 |[Q]1 " |21| | |10|31| |1,308-1,326| 47.5| " |28 |[Q]1 " |27| | |11|38| | 955-1,326| 930.0| |24 | |26| | | 9|35| | 693-1,326|1,585.0| |24 | |27| | | 8|35| -+-----------+-------+-------------+---+-------------+--+--+---+--+--| A| 216-1,326|2,777.5| |23 | |27| | | 7|34| l| 55-1,326|3,180.0| |22 | |26| | | 6|32| l| | | | | | | | | | | =+===========+=======+=============+===+=============+==+==+===+==+==|
TABLE 24 PART 2
=+===========+====+=====+=====+========+====+====+====+====+====| W| | | |Av. | | TIME FOR RING | e| | | | | | ERECTION, | i| | | |Time | | HRS. AND MIN. | g| |----+-----| | |----+----+----+----+----| h| |Av. |Time |per | | | | | | | t| |No. |Muck-| |T | O | | | | | | |of |ing, |ring,|i | r | | | | | o| |cu. |per | |m | d | B | B | | | f| |yd. |cu. |shov-|e J | i | o | o | T | | | |per |yd. |ing |a | n | r | r | a | M | | |ring| | |f c | a | e | e | p | e | i| | | |and |o k | r | | | e | a | r| Section | | | |r s | y | 1 | 2 | r | n | o| between | | |Muck-+--------+----+----+----+----+----| n| rings |E | |ing | F | G | G | G | G | G | -+-----------+----+-----+-----+--------+----+----+----+----+----| | 1-54 | | | |Time for|4-00| | |4-21|4-04| | 55-80 |41 |0-31 |21-00|jacks |6-04| | |5-30|5-57| | 81-107 |41 |0-33 |22-30|for |4-26| | | |4-26| O| 108-153 |41 |0-39 |26-31|light |3-10| | |3-30|3-12| r| 154-194 |41 |0-27 |18-34|iron is |2-08| J. | J. |2-40|2-10| d| | | | |included| | | | | | i| 195-215 |41 |0-10 | 6-46|in |3-03|3-30|3-30| |3-09| n| 216-393 |46 |0-05 | 3-53|shoving |2-40|2-56|3-00|3-10|2-50| a| 394-429 |46 |0-18 |17-09|and |3-43|3-39|4-46|4-11|3-56| r| | | | |mucking | | | | | | y| 430-509 |11 |0-10 | 1-42| |3-14|4-12|3-59|3-46|3-34| | 510-692 |30 |0-05 | 1-47| |2-08|2-21|2-32|2-50|2-18| | 55-692 |30 |0-15 | 7-35|[N] |3-02| | |4-31|3-12| | 216-692 |30 |0-07 | 3-42|[N] |2-38|2-59|3-08|1-30|2-50| -+-----------+----+-----+-----+--------+----+----+----+----+----| | 693- 954|11 |0-12 | 1-02|[N] |1-52|2-05|2-15|2-29|2-0 | | 955-1,014|12 |0-04 | 0-48|0-16 |0-51|1-18|1-08|0-50|0-58| |1,015-1,074|12 |0-03 | 0-41|0-13 |0-43|0-46|0-55|0-40|0-45| H|1,075-1,134| 8 |0-04 | 0-34|0-12 |1-04|1-01|1-15|1-20|1-08| e|1,135-1,194| 8 |0-04 | 0-33|0-13 |0-53|0-51|0-58|0-46|0-53| a|1,195-1,224| 6 |0-04 | 0-24|0-12 |0-58|0-42|0-53|0-50|0-54| v|1,225-1,262| 5 |0-05 | 0-23|0-10 |0-48|0-49|0-50|0-35|0-47| y|1,263-1,277|10 |0-04 | 0-36|0-11 |0-47|0-50|0-52|0-48|0-52| |1,278-1,307|17 |0-04 | 1-09|0-10 |1-03|1-01|1-06|0-00|1-04| |1,308-1,326|22 |0-05 | 1-39|0-18 |1-25|1-48|1-50|0-50|1-31| | 955-1,326|11 |0-04 | 0-41|0-13 |0-55|0-59|1-03|0-55|0-58| | 693-1,326|12 |0-04 | 0-51|[N] |1-27|1-34|1-41|1-38|1-31| -+-----------+----+-----+-----+--------+----+----+----+----+----| A| 216-1,326|19 |0-06 | 1-59|[N] |1-55|2-08|2-16|1-35|2-03| l| 55-1,326|21 |0-10 | 4-13|[N] | | | | |2-22| l| | | | | | | | | | | =+===========+====+=====+=====+========+====+====+====+====+====|
TABLE 24 PART 3
=+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| W| | BOLTING TIME, WHOLE |Time| | e| | TIME ON BOLTS AFTER | | | i| | RING IS COMPLETE. |lost| TOTAL TIME. | g| |----+----+----+----+----| |-----+-----+-----+-----+-----| h| | | | | | |re- | | | | | | t| | O | | | | |pair- | | | | | | | r | | | | |ing | | | | | | o| | d | B | B | | | | O | | | | | f| | i | o | o | T | |hy- | r | | | | | | | n | r | r | a | M |drau- d | B | B | | | | | a | e | e | p | e |lic | i | o | o | T | | i| | r | | | e | a | | n | r | r | a | M | r| Section | y | 1 | 2 | r | n |pip-| a | e | e | p | e | o| between |----+----+----+----+----|ing | r | | | e | a | n| rings | H | H | H | H | H | | y | 1 | 2 | r | n | -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| | 1-54 | Excavation partially completed previously. | | 55-80 |} {| |27-4 | | |26-30|26-57| O| 81-107 |} {| |26-56| | | |26-56| r| 108-153 |} {| |29-41| | |30-1 |29-43| d| 154-194 |} {| |20-42| | |21-14|20-44| i| |} {| | | | | | | n| 195-215 |} {| | 9-49|10-16|10-16| | 9-55| a| 216-393 |} Bolting time for {|0-09| 6-42| 6-58| 7-02| 7-12| 6-52| r| 394-429 |} light iron is {| |23-79|23-25|24-32|23-57|23-42| y| |} included in {| | | | | | | | 430-509 |} erection. {|0-18| 5-14| 6-12| 5-59| 5-46| 5-34| | 510-692 |} {|0-11| 4-06| 4-19| 4-30| 4-48| 4-16| | 55-692 |} {|0-17|10-54| | |12-23|11-04| | 216-692 |} {|0-25| 6-45| 7-06| 7-15| 5-37| 6-57| -+-----------|} {|----+-----+-----+-----+-----+-----| | 693- 954|} {|0-13| 3-7 | 3-20| 3-30| 3-44| 3-15| | 955-1,014|0-24|0-21|0-37|0-10|0-25|0 | 2-19| 2-43| 2-49| 2-04| 2-27| |1,015-1,074|0-31|0-30|0-52|0-23|0-34|0-02| 2-10| 2-12| 2-43| 1-59| 2-15| H|1,075-1,134|0-28|0-35|1-40|0-52|0-44|0-03| 2-21| 2-25| 3-44| 3-01| 2-41| e|1,135-1,194|0-32|0-20|0-24|0-18|0-26|0 | 2-11| 1-57| 2-08| 1-50| 2-05| a|1,195-1,224|0-19|0-20|0-34|0-35|0-23|0 | 1-53| 1-38| 2-03| 2-01| 1-53| v|1,225-1,262|0-29|0-29|0-36|0-18|0-30|0 | 1-50| 1-51| 1-59| 1-26| 1-50| y|1,263-1,277|0-23|0-23|0-41|0-23|0-27|0 | 1-57| 2-0 | 2-20| 1-58| 2-06| |1,278-1,307|0-33|0-34|0-51|0-0 |0-36|0 | 2-55| 2-54| 3-16| 0-0 | 2-59| |1,308-1,326|0-49|0-42|0-58|0-25|0-48|0 | 4-11| 4-27| 4-45| 3-12| 4-16| | 955-1,326|0-29|0-27|0-49|0-31|0-32|0 | 2-18| 2-20| 2-46| 2-20| 2-24| | 693-1,326|[O] | | | | |0-06| 2-24| 2-31| 2-38| 2-35| 2-28| -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| A| 216-1,326|[O] | | | | |0-16| | | | | 4-18| l| 55-1,326|[O] | | | | |0-12| | | | | 6-47| l| | | | | | | | | | | | | =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====|
TABLE 24 SUMMARY PART 1
===+===========+=======+==============+====+============+==+==+===+==+==| | | | 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 | ---+-----------+-------+--------------+----+------------+--+--+---+--+--| O {| 1-54 | 135.0|Rock |0 | [P] | | | | |14| r {| 55-194 | 350.0|Earth and rock|16 | [P] |22| 6|1/3| 2|30| d {| 195-393 | 497.5|Silt |20 |[P]Breasting|27| | | 4|31| i {| 394-440 | 117.5| " |24 |[P]Breasting|28| | | 4|32| n {| 441-692 | 630.0| " |23 |[Q]3 doors |25| | | 4|29| a {|-----------+-------+--------------+----+------------+--+--+---+--+--| r {| 216-692 |1,192.5| |22 | |26| | | 4|30| y {|-----------+-------+--------------+----+------------+--+--+---+--+--| {| 55-692 |1,595.0| |20 | |25| 2| | 3|30| ---+-----------+-------+--------------+----+------------+--+--+---+--+--| Hvy| 693-1,326|1,585.0|Silt |24 |[Q]1 door |27| | | 8|35| ---+-----------+-------+--------------+----+------------+--+--+---+--+--| All| 55-1,326|3,180.0| |22 | |26| | | 6|32| ===+===========+=======+==============+====+============+==+==+===+==+==|
TABLE 24 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 | [N] | [O] |time|Total| Items |hrs min| ---+--------+--------+-------+-------+----+-----+---------------+--------| O {| | | | 4-14 | | |First bulkhead |172 00| r {| 41 | 0-32 | 21-44 | 4-4 | |25-48|Second bulkhead|119 00| d {| 38 | 0-7 | 4-11 | 2-52 |0-9 | 7-12|Grouting |200 00| i {| 41 | 0-18 | 11-54 | 4-17 |1-41|17-52|Blowout | 73 00| n {| 17 | 0-6 | 2-04 | 2-34 |0-42| 5-20|Cradle |100 00| a {|--------+--------+-------+-------+----+-----+---------------+--------| r {| 30 | 0-7 | 3-42 | 2-50 |0-25| 6-57|Total |664 00| y {|--------+--------+-------+-------+----+-----+---------------+--------| {| 30 | 0-15 | 7-35 | 3-12 |0-17|11-04|Per ring | 0 30| ---+--------+--------+-------+-------+----+-----+---------------+--------| Hvy| 12 | 0-4 | 0-51 | 1-31 |0-06| 2-28| | | ---+--------+--------+-------+-------+----+-----+---------------+--------| All| 21 | 0-10 | 4-13 | 2-22 |0-12| 6-47| | | ===+========+========+=======+=======+====+=====+===============+========|
[N] Including time for jacks.
[O] Including bolting time.
[P] Excavating ahead of shield.
[Q] Shoving shield into silt with ... doors open.
TABLE 25.--SHIELD-DRIVEN TUNNEL WORK, MANHATTAN SHAFT, RIVER TUNNEL SOUTH. Table showing the size of the gang, the amount of excavation, and the time per ring taken for the various operations involved in building tunnel through the several kinds of ground encountered; also the extent and nature of all the unavoidable delays.
TABLE 25 PART 1