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10 - 1
CHAPTER
10
Excavators, Draglines, and Clamshells
1.
Fill factor for front shovel for common earth is found in Table 10.1 to be 1.025 by
taking the average for earth.
𝑚𝑖𝑛.)(60𝑚𝑖𝑛.
ℎ𝑟. )
2. a.
Fill factor for front shovel for bank clay is found in Table 10.1 to be 1.025 by
taking the average for bank clay.
Correction Factor from Table 10.2 is 0.86.
ℎ𝑟. )
3. Fill factor for front shovel for rock-earth mixture is found in Table 10.1 to be 1.025 by taking
the average for rock-earth mixture.
Correction Factor from Table 10.2 is 0.86.
ℎ𝑟. )
4.
Assume average conditions and determine productivity in BCY per hour. From Table
10.6, the average cycle time is 26 sec. Average fill factor for hard, tough clay from
Table 10.5 is 0.85.
(26 𝑠𝑒𝑐.)(1.18𝐿𝐶𝑌
𝐵𝐶𝑌)=𝟑𝟖𝟐 𝑩𝑪𝒀
5. a.
Average fill factor for hard, tough clay from Table 10.5 is 0.85. Average cycle time
from Table 10.6 is 17 sec.
10 - 3
𝑚𝑖𝑛.)(45𝑚𝑖𝑛.
ℎ𝑟. )
(17 𝑠𝑒𝑐.)(1.33𝐿𝐶𝑌
𝐵𝐶𝑌)(27 𝑐𝑢.𝑓𝑡.
𝑐𝑢.𝑦𝑑.)=𝟕𝟏.𝟒 𝑩𝑪𝒀
5. b.
(27 𝑐𝑢.𝑓𝑡.
𝑐𝑢.𝑦𝑑.)(16 ℎ𝑟.) =55.6 𝐵𝐶𝑌
Average fill factor for sandy clay soil from Table 10.5 is 1.05.
Assume that required bucket size is less than 1 cu. yd., which means cycle time is
17 sec. from Table 10.6.
7. a.
Average fill factor for hard, tough clay from Table 10.5 is 0.85. Average cycle time
from Table 10.6 is 23 sec.
𝑚𝑖𝑛.)(30𝑚𝑖𝑛.
ℎ𝑟. )
7. b.
ℎ𝑟. )
10 - 4
8. a.
Ideal cycle time for 2 LCY bucket excavating clay from Table 10.9 is 27 sec.
ℎ𝑟.)
(27 𝑠𝑒𝑐.)(1.22 𝐿𝐶𝑌
𝐵𝐶𝑌)=218.6 𝐵𝐶𝑌
Optimal Depth from Table 10.10 is 11.8 ft.
Correction Factor from Table 10.11 is 0.91.
8. b.
8. c.
10 - 5
9.
ℎ𝑟.)
Correction Factor from Table 10.11 is 0.88.
10.
Assume average ideal cycle time of 30 sec.
ℎ𝑟.)
(30 𝑠𝑒𝑐.)(1.13𝐿𝐶𝑌
𝐵𝐶𝑌)=212 𝐵𝐶𝑌
Correction Factor from Table 10.14 is 0.91.
ℎ𝑟. )(0.91)(0.67)=𝟏𝟐𝟗 𝑩𝑪𝒀
𝒉𝒓.
11. a.
ℎ𝑟.)
10 - 6
Operating Factor from Table 10.3 is 0.78.
11. b.
ℎ𝑟. )
11. c.
(323𝐿𝐶𝑌
ℎ𝑟. )=$𝟎.𝟔𝟐
12. a.
Try 2 cu. yd. bucket:
Try 1.5 cu. yd. bucket:
12. b.
10 - 7
ℎ𝑟.)
12. b. (continued)
ℎ𝑟. )
