===+========+========+=======+=======+====+=====+===============+========|
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.