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 | [T] | [U] |time|Total|Items |hrs min| ---+--------+--------+-------+-----+----+-----+------------------+-------| O {| 41 | 0-14 | 9-53 | 5-07| |15-00|First bulkhead |160 00| r {| 54 | 0-19 | 17-20 | 2-26|0-05|19-51|Second bulkhead |157 45| d {| 37 | 0-09 | 5-39 | 2-47|0-63| 9-29|Grouting |200 00| i {| | | | | | | | | n {| 40 | 0-17 | 12-42 | 3-27|0-38|16-47|Blowout | 69 45| a {| | | | | | | | | r {| 24 | 0-05 | 1-58 | 2-29|0-22| 4-49|Waiting-heavy iron| 64 00| y {|--------+--------+-------+-----+----+-----+------------------+-------| {| 30 | 0-07 | 3-27 | 2-42|0-18| 6-27|Total |715 30| {|--------+--------+-------+-----+----+-----+------------------+-------| {| 36 | 0-11 | 6-40 | 2-52|0-15| 9-47|Per ring | 0 39| ---+--------+--------+-------+-----+----+-----+------------------+-------| Hvy| 18 | 0-05 | 1-29 | 1-45|0-06| 3-19| | | ---+--------+--------+-------+-----+----+-----+------------------+-------| All| 29 | 0-09 | 4-36 | 2-25|0-14| 7-15| | | ===+========+========+=======+=====+====+=====+==================+=======|

[R] Excavating ahead of shield.

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

[T] Including time for jacks.

[U] Including bolting time.

TABLE 26.--SHIELD-DRIVEN TUNNEL WORK, WEEHAWKEN 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 26