Chapter VI: Part 6

===+===========+=======+==============+====+============+==+===+===+==+==|
| | | 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 {| 1-24 | 60.0|Rock | 0 | [X] | 9|.04| 0 | 0|10|
r {| 25-55 | 77.5| " |20 | [X] |14|5 |0.5| 1|21|
d {| 56-72 | 42.5|Mixed sand and|10 |[X]Breasting|22|2 |.09| 2|26|
i {| | |rock | | | | | | | |
n {| 73-165 | 232.5|Sand & gravel |10 |[X]Breasting|22|0 |.1 | 2|24|
a {| 166-184 | 47.5|Sand and silt |20 {|[X]Breasting|22|0 |.38| 3|25|
r {| | |with piles | {|and cutting | | | | | |
y {| 185-253 | 172.5|Silt w/ piles |24 {|piles |23|0 |.71| 3|26|
{| 254-640 | 110.0|Silt |26 |[Y]Doors |22|0 | 0 | 3|25|
{|-----------+-------+--------------+----+------------+--+---+---+--+--|
{| 25-640 |1,540.0| |20 |[Y]Doors |21|0.3|.12| 3|24|
---+-----------+-------+--------------+----+------------+--+---+---+--+--|
Hvy| 641-1,110|1,175.0| |28 | |21| 0 | 0 | 7|28|
---+-----------+-------+--------------+----+------------+--+---+---+--+--|
All| 25-1,110|2,715.0| |26 | |21|0.1|0.1| 3|24|
===+===========+=======+==============+====+============+==+===+===+==+==|

TABLE 26 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 | [V] | [W] |time|Total| Items |hrs min| ---+--------+--------+-------+-------+----+-----+---------------+--------| O {| 46 | 0-06 | 4-32 |6-23 |0-00|10-55|First bulkhead |132-00 | r {| 46 | 0-51 |39-33 |4-29 |0-00|44-02|Second bulkhead|158-50 | d {| 44 | 0-21 |15-05 |2-55 |0-04|18-04|Grouting |240-00 | i {| | | | | | |Old cave-in |234-00 | n {| 39 | 0-11 | 6-56 |2-26 |0-09| 9-31|shoving tube |128-00 | a {| 42 | 0-09 | 6-19 |2-37 |0-07| 9-03|---------------+--------| r {| | | | | | | Total |892-50 | y {| 43 | 0-09 | 6-13 |2-15 |0-05| 8-43|---------------+--------| {| 11 | 0-07 | 1-13 |2-20 |0-08| 3-41| per ring | 0-49 | {|--------+--------+-------+-------+----+-----+---------------+--------| {| 24 | 0-14 | 5-06 |2-24 |0-08| 7-38| | | ---+--------+--------+-------+-------+----+-----+---------------+--------| Hvy| 8 | 0-04 | 0-44 |1-40 |0-11| 2-35| | | ---+--------+--------+-------+-------+----+-----+---------------+--------| All| 17.1 | 0-12 | 3-13 |3-05 |0-09| 5-27| | | ===+========+========+=======+=======+====+=====+===============+========|

[V] Including time for jacks.

[W] Including bolting time.

[X] Excavating ahead of shield.

[Y] Shoving shield into silt with ... doors open.

TABLE 27.--SHIELD-DRIVEN TUNNEL WORK, WEEHAWKEN 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 27 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 | | -+-----------+-------+------------+----+------------+--+--+---+---+--| | 1-27 | 67.5|Rock | 9 |[C] {|Excavation }| | | | | | {|partially }| | | | | | {|completed }| | | | | | {|previously. }| | 28-42 | 37.5| " |12 |[C] |13| 4|1 |1 |19| | 43-58 | 40.0|Rock or |12 |[C] |19| 2|2 |2 |25| | | | | | | | | O| 59-153 | 237.5|Gravel and |16 |[C]Breasting|25| |1 |4 |30| r| | |sand | | | | | | | | d| 154-170 | 42.5|Sand and |18 | " |26| |1 |5 |32| i| | |silt w/piles| | | | | | | | n| 171-236 | 165.0|Silt with |22 |Top half |22| |1 |3 |26| a| | |piles | | r| 237-259 | 57.5|Silt |25 |[D]1 door |18| |1 |3 |22| y| 260-302 | 107.5| " |27 |[D]1 door |15| | |2 |17| | 303-350 | 120.0| " |27 |[D]8 doors |15| | |4 |19| | 351-378 | 70.0| " |27.5|[D]8 " |18| | |6 |24| | 379-424 | 115.0| " |27.5|[D]8 " |19| | |4 |23| | 425-522 | 245.0| " |28 |[D]1 door |19| | |4 |23| | 523-625 | 257.5| " |28 |[D]1 " |20| | |4 |24| | 171-625 |1,137.5| |27 | |19| | |4 |23| | 28-625 |1,495.0| |25 | |19|.8|0.8|3.4|24| -+-----------+-------+------------+----+------------+--+--+---+---+--| | 626-649 | 57.5|Silt |28 |[D]1 door |16| | | 3 |19| | 650-733 | 210.0| " |28 |[D]8 doors |19| | | 4 |23| | 734-753 | 50.0| " |28 |[D]8 " |24| | | 5 |29| H| 754-844 | 227.5| " |28 |[D]8 " |26| | | 8 |34| e| 845-859 | 37.5| " |28 |[D]8 " |27| | | 9 |36| a| 860-899 | 100.0| " |28 |[D]8 " |24| | | 8 |33| v| 900-935 | 90.0| " |28 |[D]1 door |25| | | 7 |32| y| 936-963 | 70.5| " |28 |[D]1 " |25| | | 8 |33| | 964-1,003| 100.0| " |28 |[D]1 " |25| | |10 |35| |1,004-1,060| 142.5| " |28 |[D]1 " |26| | |10 |36| |1,061-1,110| 125.0| " |28 |[D]1 " |37| | |10 |47| |1,111-1,238| 320.0| " |28 |[D]1 " |30| | | 9 |39| |1,239-1,312| 185.0| " |28 | |39| | | 9 |38| | 626-1,312|1,717.5| " |28 | |35| | | 8 |33| -+-----------+-------+------------+----+------------+--+--+---+---+--| A| 171-1,312|2,855.0| |28 | |23| | | 6 |29| l| 28-1,312|3,212.5| |26 | |21| | | 5 |26| l| | | | | | | | | | | =+===========+=======+============+====+============+==+==+===+===+==|

TABLE 27 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 | -+-----------+----+-----+-----+--------+----+----+----+----+----| | 1-27 |Excavation| | |8-30| | |3-45|8-08| | | partially| | | | | | | | | | completed| | | | | | | | | |previously| | | | | | | | | 28-42 |48.7|0-25 |20-33| |4-23| | |4-00|4-21| | 43-58 |44.2|0-46 |33-44| |4-16| | |5-45|4-44| | | | | | | | | | | | O| 59-153 |39.0|0-12 | 8-06| |2-19| | |4-18|2-23| r| | | | | | | | | | | d| 154-170 |41.6|0-10 | 7-10| |2-00| J. | J. |1-48|1-59| i| | | | | | | | | | | n| 171-236 |42.6|0-10 | 7-23| |2-36|2-55|2-58|1-24|2-35| a| | | | | | | | | | | r| 237-259 |13.8|0-11 | 2-29| |3-01|2-05|1-28|2-00|2-32| y| 260-302 | 0 | | 0-32| |2-34|2-35|3-38|4-28|3-05| | 303-350 | 6.9|0-07 | 0-52| |2-59|2-28|2-37|1-44|2-41| | 351-378 | 0 | | 0-33| |2-05|2-32|2-48|2-00|2-18| | 379-424 | 6.9|0-07 | 0-48| |3-34|2-51|3-18|3-19|3-22| | 425-522 | 6.7|0-06 | 0-45| |3-09|3-51|3-00|3-28|3-16| | 523-625 | 0 | | 0-32| |1-36|1-37|1-47|1-51|1-39| | 171-625 | 9.7|0-11 | 1-44| [A] |2-37|2-41|2-41|2-32|2-38| | 28-625 |17.8|0-14 | 4-14| [A] | | | | |2-41| -+-----------+----+-----+-----+--------+----+----+----+----+----| | 626-649 |12.2|0-12 | 2-23| [A] |2-19|2-30|2-05|1-42|2-16| | 650-733 |13.5| | 0-57| 0-13 |1-42|1-24|1-47|1-48|1-39| | 734-753 | 8.3|0-05 | 0-41| 0-17 |1-06|1-55|0-38|1-20|1-12| H| 754-844 |12.8|0-04 | 0-51| 0-16 |1-19|1-41|1-52|0-50|1-29| e| 845-859 | 5.6|0-07 | 0-39| 0-19 |1-24|1-08|1-10| |1-20| a| 860-899 |16.5|0-02 | 0-39| 0-13 |1-00|1-05|1-13| |1-04| v| 900-935 |11.5|0-03 | 0-29| 0-14 |0-47|1-13|0-52|1-10|0-52| y| 936-963 | 5.9|0-03 | 0-19| 0-15 |0-59|0-47|0-55| |0-56| | 964-1,003| 8.1|0-03 | 0-27| 0-10 |0-51|0-52|1-05| |0-53| |1,004-1,060| 8.7|0-03 | 0-30| 0-15 |1-01|1-09|1-05|0-45|1-03| |1,061-1,110| 6.2|0-03 | 0-19| 0-10 |0-42|0-49|0-54|0-45|0-45| |1,111-1,238|15.6|0-02 | 0-38| 0-16 |0-48|1-06|1-04|1-23|0-56| |1,239-1,312|13.0|0-03 | 0-36| 0-18 |1-04|1-01|1-02|1-15|1-07| | 626-1,312|10.6|0-04 | 0-42| 0-14 |1-06|1-15|1-16|1-18|1-10| -+-----------+----+-----+-----+--------+--- |----+----+----+----| A| 171-1,312|10.2|0-07 |1-15 | [A] |2-09|2-13|2-21|2-20|2-13| l| 28-1,312|14.1|0-10 |2-28 | [A] | | | | |2-18| l| | | | | | | | | | | =+===========+====+=====+=====+========+====+====+====+====+====|

TABLE 27 PART 3

=+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====| W| | BOLTING TIME, WHOLE |Time| | e| | TIME ON BOLTS AFTER | | | i| | RING IS COMPLETE. |lost| TOTAL TIME. | g| |----+----+----+----+----| |-----+-----+-----+-----+-----| h| | | | | | |re- | | | | | | t| | S | | | | |pair- | | | | | | | t | | | | |ing | | | | | | o| | r | B | B | | | | s | | | | | f| | a | o | o | T | |hy- | t | | | | | | | i | r | r | a | M |drau- r | B | B | | | | | g | e | e | p | e |lic | a | o | o | T | | i| | h | | | e | a | | i | r | r | a | M | r| Section | t | 1 | 2 | r | n |pip-| g | e | e | p | e | o| between |----+----+----+----+----|ing | h | | | e | a | n| rings | H | H | H | H | H | | t | 1 | 2 | r | n | -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| | 1-27 |} {|0-14|21-11| | |16-26|20-49| | |} {| | | | | | | | |} {| | | | | | | | |} {| | | | | | | | 28-42 |} {|0-12|25-08| | |24-45|25-06| | 43-58 |} {|1-15|39-15| | |40-44|39-43| | |} {| | | | | | | O| 59-153 |} {|0-30|10-55| | |12-54|10-59| r| |{ {| | | | | | | d| 154-170 |} {|0-00| 9-10| J. | J. | 8-58| 9-09| i| |} {| | | | | | n| 171-236 |} Bolting time for {|0-05|10-04|10-23|10-26| 8-52|10-03| a| |} light iron is {| | | | | | | r| 237-259 |} included in {|0-20| 5-50| 4-54| 4-17| 4-49| 5-21| y| 260-302 |} erection. {|0-08| 3-14| 3-15| 4-18| 5-08| 3-45| | 303-350 |} {|0-07| 3-58| 3-27| 3-36| 2-43| 3-40| | 351-378 |} {|0-17| 2-55| 3-22| 3-38| 2-50| 3-08| | 379-424 |} {|0-25| 4-47| 4-09| 4-31| 4-32| 4-35| | 425-522 |} {|0-16| 4-10| 4-52| 4-01| 4-29| 4-17| | 523-625 |} {|0-12| 2-20| 2-21| 2-31| 2-35| 2-23| | 171-625 |} {|0-13| 4-34| 4-38| 4-38| 4-29| 4-35| | 28-625 |} {|0-16| | | | | 7-11| -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| | 626-649 |1-01|1-04|1-04|0-50|1-01|0-32| 6-15| 6-29| 6-04| 5-27| 6-12| | 650-733 |1-15|0-52|0-55|0-42|1-07|0-32| 4-39| 3-58| 4-24| 4-12| 4-28| | 734-753 |0-38|0-44|1-13|0-20|0-44|0-06| 2-48| 3-43| 2-55| 2-44| 3-00| H| 754-844 |0-39|0-50|0-54|0-40|0-44|0-25| 3-30| 4-08| 4-18| 3-02| 3-45| e| 845-859 |0-45|0-15|0-15| |0-37|0-48| 3-55| 3-09| 3-11| | 3-43| a| 860-899 |0-59|0-32|0-49| |0-52|0-07| 2-58| 2-36| 3-01| | 2-55| v| 900-935 |0-39|0-43|0-32|0-20|0-38|0-04| 2-18| 2-43| 2-11| 2-17| 2-17| y| 936-963 |0-34|0-16|0-41| |0-32|0-37| 2-44| 2-14| 2-47| | 2-39| | 964-1,003|0-32|0-45|0-37| |0-35|0-16| 2-16| 2-30| 2-35| | 2-21| |1,004-1,060|0-54|0-37|0-49|0-40|0-49|0-24| 3-04| 2-55| 3-03| 2-34| 3-01| |1,061-1,110|0-24|0-26|0-39|0-25|0-27|0-00| 1-35| 1-44| 2-02| 1-39| 1-41| |1,111-1,238|0-36|0-34|0-57|1-12|0-41|0-02| 2-20| 2-36| 2-57| 3-31| 2-33| |1,239-1,312|0-39|0-43|1-12|0-59|0-50|0-10| 2-47| 2-48| 3-18| 3-18| 3-01| | 626-1,312|0-45|0-40|0-52|0-54|0-47|0-16| 3-03| 3-07| 3-20| 3-24| 3-09| -+-----------+----+----+----+----+----+----+-----+-----+-----+-----+-----| A| 171-1,312| [C]| | | | |0-15| 3-39| 3-43| 3-51| 3-50| 3-43| l| 28-1,312| [C]| | | | |0-15| | | | | 5-01| l| | | | | | | | | | | | | =+===========+====+====+====+====+====+====+=====+=====+=====+=====+=====|

TABLE 27 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 |
---+-----------+-------+--------------+----+------------+--+--+---+---+--|
{| 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.

All materials of construction were loaded on cars on the surface at the point where they were stored, and hauled on these to the elevators, sent down the shaft, and taken along the tunnels to the desired point without unloading.

The narrow-gauge railway on the surface and in the tunnel was of 2-ft. gauge with 20-lb. rails. About 70 flat cars and 50 mining cars were used at each shaft. On the surface at Manhattan these were moved by hand, but at Weehawken, where distances were greater, two electric locomotives on the overhead trolley system were used.

_Tunnel Transportation._--The mining cars shown in Fig. 19 were of 1¼ cu. yd. capacity. The short wheel base and unbalanced loading caused a good many upsets, but they were compact, easily handled, and could be dumped from either side or end.

The flat cars shown in Fig. 20 were of 3 tons capacity, and could hold two tunnel segments. As the working face was down grade from the shafts, the in-bound cars were run by gravity. For out-bound cars a cable haulage system was used, consisting of double-cylinder, Lidgerwood, single friction-drum, hoisting engines (No. 32) of 6 h.p., with cylinders 5 in. in diameter and 6 in. stroke and drums 10 in. in diameter. These were handily moved from point to point, but, as there was no tail rope, several men had to be used to pull the cable back to the face. After the second air-lock bulkhead walls had been built, a continuous-cable system, worked electrically, was put in each tunnel between the first and second air-locks.

The engine consisted of an electric motor driving a 3-ft. 6-in. drum hoist around which a ¾-in. steel wire cable passed three times. The cable was led around a sheave, down the tunnel on the right side of the in-bound track, and returned on the left side of the out-bound track. It was then carried around a set of sheaves, where a tension of 1,000 lb. was supplied by a suspended weight which acted on a sheave with a sliding axle on the tension carriage. The cable was supported throughout its length on 8-in. pulleys set in the floor at 50-ft. intervals. All the guide sheaves were 36 in. in diameter.

Each car was attached to the cable by a grip at its side. This was fastened and unfastened by hand, but was automatically released just before reaching the turn in the cable near each lock. This system could haul without difficulty an unbalanced load of 10 muck cars, spaced 100 ft. apart, up a 2% grade. The cable operated over about 1,000 ft. of tunnel, the motor being placed at the top of the grade. The driving motor was of the semi-armored, 8-pole, series-wound type, rated at 25 h.p., 635 rev. per min., and using direct current at 220 volts. The speed of handling the cars was limited by their having to pass through the air-locks on a single track. As many as 106 cars have been hauled each way in one 8-hour shift.

_Disposal._--At Manhattan the tunnel muck was carried from the elevator over the upper level of the yard trestle and dumped into bins on the 33d Street side, whence it was teamed to the public dump at 30th Street and North River. At Weehawken the rock excavation was removed by the Erie Railroad on flat cars on which it was dumped by the tunnel contractor, but all the silt muck was teamed away to some marshy ground where dumping privileges were obtained.

The typical forces employed on transportation were as follows:

_Receipt and Unloading of Material: Surface Transportation and Disposal._

At Manhattan Shaft, on 10-hour shifts:

2 Engineers on derricks. @ $3.00 per day.
2 Foremen. " 3.25 " "
15 Laborers loading and unloading iron. " 1.75 " "
7 Laborers on disposal. " 1.75 " "
6 Teams. " 7.50 " "

At Weehawken Shaft, on 10-hour shifts:

3 Engineers on derricks and locomotives. @ $3.00 per day.
16 Laborers loading and unloading iron. " 1.75 " "
3 Foremen. " 3.50 " "
11 Laborers on disposal. " 1.75 " "
6 Teams on disposal. " 6.50 " "

Tunnel Transportation (Including Shaft Elevator):

Shaft elevators and to and from the first air-lock on 10-hour shift:

2 Engineers. @ $3.00 per day.
2 Signalmen. " 2.00 " "
1 Foreman. " 3.00 " "
12 Laborers. " 1.75 " "

Between first lock and working face, on 8-hour shifts, the force varied:

From 1 to 3 (average 2) Hoist engineers @ $3.00 per day.
From 0 to 2 (average 1) Lockman " 2.75 " "
From 1 to 2 (average 2) Trackmen " 3.00 " "
From 2 to 7 (average 4) Cablemen
(pulling back cable) " 3.00 " "

_Pumping._--The water was taken out of the invert by a 4-in. blow-pipe which was always kept up to a point near the shield and discharged into the sump near the shaft.

When the air pressure was removed and the blow-pipe device, consequently, was unavailable, small Cameron pumps, driven by compressed air, and having a capacity of about 140 gal. per hour, were used, one being set up wherever it was necessary to keep the invert dry; for example, at points where caulking was in progress.

_Lighting._--The tunnels were lighted by electricity, the current being supplied, at a pressure of 250 volts, from the dynamos in the contractor's power-house.

Two 0000 wire cables were used as far as the second air-locks, about 1,650 ft. from the power-house, on each side; and beyond that point, to the junction of the shields (about 1,750 ft.), 00 and 0 wires were used. These cables also carried the current for the cable haulage system. Two rows of 16-c.p. lamps, provided with reflectors, were used in each tunnel; one row was along the side just above the axis, with the lights at about 30-ft. intervals; the other along the crown, with the lamps halfway between the side lamps, also at 30-ft. intervals. At points where work was in progress three groups of 5 lights each were used. The tunnels as a whole were well lighted, and in consequence work of all kinds was much helped.

_Period No. 2._--_Caulking and Grummeting._--_November, 1906, to June, 1907._--After the metal lining had been built completely across the river in both tunnels, the work of making it water-tight was taken up. This consisted in caulking into the joints between the plates a mixture of sal-ammoniac and iron borings which set up into a hard rusty mass, and in taking out each bolt and placing around the shank under the washer at each end a grummet made of yarn soaked in red lead. These grummets were made by the contractor on the works, and consisted of three or four strands of twisted hemp yarn, known as "lath yarn," making up a rope-like cross-section about ¼ in. in diameter. Usually, one of these under each washer was enough, but in wet gravel, or where bolts were obliquely in the bolt-holes, two were used at each end. After pulling the grummets in, all the nuts were pulled up tight by wrenches about 3 ft. long, with two men on one wrench. Bolts were not passed as tight unless the nut resisted the weight of an average man on a 2½-ft. wrench.

Before putting in the caulking mixture, the joints were carefully scraped out with a special tool, cleaned with cotton waste, and washed with a stream of water. The usual mixture for sides and invert was about 2 lb. of sal-ammoniac and 1 lb. of sulphur to 250 lb. of iron filings or borings. In the arch, 4 lb. of sal-ammoniac and 3 lb. of sulphur to 125 lb. of filings was the mixture. A small hand-hammer was used to drive the caulking tool, but, in the sides and invert, air hammers were used with some advantage. The success of work of this kind depends entirely on the thoroughness with which the mixture is hammered in; and the inspection, which was of an exceedingly monotonous nature, called for the greatest care and watchfulness on the part of the Company's forces, especially in the pocket iron, where each bolt had to be removed, the caulking done at the bottom of the pockets put in, the bolts replaced; and the rest of the pockets filled. The results have been satisfactory, as the leakage under normal air and prior to placing the concrete averaged about 0.14 gal. per lin. ft. of tunnel per 24 hours, which is about 0.0035 gal. per lin. ft. of joint per 24 hours. With each linear foot of joint is included the leakage from 1.27 bolts. Afterward, when the concrete lining was in, the leakage was found to be about 0.05 to 0.06 gal. per lin. ft. of tunnel per 24 hours, which compares favorably with the records of other lined tunnels. The typical gang employed on this work was as follows:

_In Pocket Iron:_

1 General foreman @ $5.00 per day.
1 Mixer " 3.00 " "
1 Nipper " 3.00 " "
5 Caulkers " 3.00 " "
10 Grummeters " 3.00 " "

_In Pocketless Iron:_

1 General foreman @ $5.00 per day.
1 Mixer " 3.00 " "
1 Nipper " 3.00 " "
3 Caulkers " 3.00 " "
12 Grummeters " 3.00 " "

The average amount of caulking and grummeting done per shift with such a gang was (with pocketless grooves), 348 lin. ft. of joint and 445 bolts grummeted; and in pocket iron: 126 lin. ft. of joint and 160 bolts grummeted.

The caulking and grummeting work was finished in June, 1907, this completing the second period.

_Period No. 3._--_Experiments, Tests, and Observations._--_April, 1907, to April, 1908._--The third period, that of tests and observations in connection with the question of foundations, is dealt with in another paper. It occupied from April, 1907, to November, 1908. The results of the information then gathered was that it was not thought advisable to go on with the foundations.

_Period No. 4._--_Capping Pile Bores, Sinking Sumps, and Building Cross-Passages._--_April, 1908, to November, 1908._--In order to reduce the leakage from the bore segments to the least possible amount before placing the concrete lining, it was decided to remove the plugs and replace them with flat cover-plates; these have been described before, together with the filling of Bore Segments No. 2 with mortar to reduce the leakage around the distance piece.

During this period the turnbuckles to reinforce the broken plates were put in, and the sump sunk at the lowest point of the tunnel. These sumps have been described in a previous part of this paper; they were put down without trouble. As much as possible of the concrete lining was put in before the lining castings were taken into the tunnel, as the space inside was very restricted. The first lining casting was bolted to the flat flanges of the sump segment, the bolts holding the latter to the adjacent segments were removed, and the whole was forced down with two of the old shield jacks, taking a bearing on the tunnel. The two together exerted a pressure of about 150 tons. The plugs in the bottom of the sump segment were taken out, and pipes were put in, through which the silt squeezed up into the tunnel and relieved the pressure on the sump segment.

If the silt did not flow freely, a water-jet was used. The sump was kept plumb by regulating the jacks. In this way the sump was sunk, adding lining sections one by one, and finally putting on the top segment, which was composed of three pieces.

The time taken to sink one sump was about 4 days, working one 8-hour shift per day, and not counting the time taken to set up the jacks and bracing. The sinking of each section took from 4 to 6 hours. The air pressure was 25 lb. and the hydrostatic head 41 lb. per sq. in. The force was 1 assistant superintendent at $6.00 per day, 1 foreman at $4.50, and 6 laborers at $3.00 per day.

_Cross-Passages._--It was during this period that the five cross-passages previously mentioned were built. In the case of those in the rock, careful excavation was needed so as to avoid breaking the iron lining. Drilling was done from both ends, the holes were closely spaced, and about 2 ft. 6 in. deep, and light charges of powder were used. The heading, 5 by 7 ft. in cross-section, was thus excavated in five lengths, with 24 holes to a length, and about 23 lin. ft. of hole per yard. About 5.3 lb. of powder per cu. yd. was used. The sides, top, and bottom were then drilled at a very sharp angle to the face and the excavation was trimmed to the right size. This widening out took about 7½ ft. of hole per cu. yd., and 0.9 lb. of powder.

In the passages in silt the excavation had to be 12 ft. wide and 13 ft. 8 in. high to give enough room inside the timbers. The plates at one end of the passage were first removed. An air pressure of 17 lb. was carried, which was enough to keep the silt from squeezing in and yet left it soft enough to be chopped with a spade.

A top heading, of full width and 6 ft. 8 in. high, was first taken out, and the roof was sheathed with 2-in. boards held by 10 by 10-in. head trees at 3-ft. centers, with 10 by 10-in. side trees. The lower 7 ft. of bench was then taken out, a tight floor of 6 by 6-in. cross-timber was put in, and also longer side trees, the head trees being temporarily held by two longitudinal 10 by 10-in. stringers blocked in place. The bulk of the space between the side trees was filled with 10 by 10-in. posts and blocking. The plates at the other end of the passage were then taken out from the other tunnel.

After the excavation was out, the outer reinforced concrete lining was built. Rough forms were used, as the interior surfaces of the passages were to be rendered with a water-proofing cement. A few grout pipes were built in, and all voids outside the concrete were grouted. Grouting was also done through the regular grout holes of the metal lining around the openings.

In the case of the most westerly of the cross-passages at Weehawken, which was in badly seamed rock carrying much water, a steel inter-lining, rather smaller than the concrete, was put in. The space between the concrete and the steel was left open, so that water coming through the concrete lining was stopped by the steel plate. This water was led back to the shield chamber in a special drain laid in the bench of the river tunnel and behind the ducts. From the shield chamber the water ran with the rest of the drainage from the Weehawken Land Tunnels to the Weehawken Shaft sump.

_Period No. 5._--_Placing the Concrete Lining._--_November, 1908, to June, 1909._--During the fifth period the concrete lining was put in. This lining was placed in stages, as follows: First, the invert; second, the duct bench; third, the arch; fourth, the ducts; and fifth, the face of the bench. This division can be seen by reference to Fig. 21.

All the work was started on the landward ends and carried toward the middle of the river from both sides. Except where the Weehawken force passed the lowest point of the tunnel, which is at Station 241 or nearly 900 ft. to the west of the middle of the river, all the work was down grade.

Before any concrete was placed, the surface of the iron was cleaned with scrapers and wire brushes, and washed with water. Any leaks in the caulking and grummeting (finished by June, 1907, and therefore all more than 12 months old) were repaired. All the grout hole plugs were examined, and the plugs in any leaking ones were taken out, smeared with red lead, and replaced. The leakage in the caulking was due to the fact that the tunnel had been settling slightly during the whole 12 months of pile tests, and, therefore, had opened some of the joints. After the caulking had been repaired and the surface thoroughly cleaned, the flanges were covered with neat cement (put on dry or poured on in the form of thick grout) just before the concrete was placed.

_Invert Concrete._--The form used for the landward type of concrete, that is, the one with a middle drain, consisted of a frame made of a pair of trussed steel rails on each side of the tunnel and connected at intervals with 6 by 6-in. cross-timbers; two "wing forms" were hung from this frame by adjustable arms. These wings formed the curved sides of the invert, the lip, and the form for the middle drain. The whole form was supported on three wheels, two on the rear end running on a rail laid on the finished concrete, and the third in front attached to the frame by a carriage and running on a rail temporarily laid on the iron lining. The form was braced from the iron lining by 6 by 6-in. blocks.

For the soft-ground type of invert, namely, the one without the middle drain, a form of the same general type was used, except that the form for the middle drain was removed. After the form had been in use for some time, "key pieces" (made of strips of wood about 1 ft. 3 in. in length and 3 by 3 in. in cross-section) were nailed circumferentially on the under side of the wings at 2-ft. intervals. This was done because, at the time, it was not known whether ballasted tracks or some form of rigid concrete track construction would be adopted, and, if the latter, it was desirable not to have the surface smooth.

The concrete was received in cars at the rear end of the form and dumped on a temporary platform. It was then loaded into wheel-barrows on the runways, as shown in Fig. 22. The concrete was thrown from the barrows into the invert, where it was spaded and tamped.

In cases where there was steel-rod reinforcement, the concrete was first brought up to the level of the underside of these rods, which came between the wings; the rods were laid in place, and then more concrete was placed over the rods and brought up to the level of the bottom of the wings. Where there was no reinforcement, the concrete was brought up in one lift.