lecture 10

Question 1

Profile

Answer 1

needs to start at elevation of starting point and end at elevation of ending point.

Question 2

To reduce earthwork and overall construction cost

Answer 2

#Set gradeline / profile as close as possible to natural ground level.
#Balance excavated volume (cut) with the embankment volume (fill)

Question 3

Earthwork calculations

Answer 3

#Take cross sections at regular intervals along profile (commonly every 20 m).
#Plot Natural ground level and profile grade level to indicate areas of fill and cut.
# At each cross section plot using scale areas of cut and fill.

Question 4

How to approximate volume of earthwork between two consecutive stations
If both sections are cut or fill

Answer 4

Apply average end area method

Vcut or Vfill equal to (A1(of first cross section) +A2(of second cross section)) /2 * distance between

Question 5

If one section has both cut and fill

Answer 5

(A1+A2’)/2*distance

A2’‘/2 *distance

Question 6

one section is cut and the other is fill

Answer 6

See slide 22

Question 7

Earthwork costs

Answer 7

These costs depend on:
– Total cut and fill
– Balance between cut and fill
– Material transport
-also depend on type of soil,
retaining structures, earth reinforcement, etc.

Question 8

Depth and heights of cut and fill sections

Answer 8

Cuts:
_Greatest depth of 10 m.
_Desirable max depth of 7m
with greater cut depths we will have slope instability and excessive costs
Fills
_Maximum fill height of 10m
_Desirable maximum height of fill is 7m , else it may be more economical to build a bridge.

Question 9

Side Slopes in Cut and Fill

Answer 9

#Gradient of side slope 1V for 3H or flatter 
#In case of high cut or fill (4.5 m and above) or in area with steep terrain implies we can use gradients of 1V for 2 Horizental
#flatter slopes depending on soil types and vegetation
#steeper slopes on rocks
# retaining wall may be utilized for steep slopes

Question 10

It is common to move material from cut areas to fill areas of highway

Answer 10

True

Question 11

Materials from cut sections are compacted in fill sections that is why we have a less volume of fill however and that is why we apply a shrinkage factor for the cut volumes

Answer 11

true

Question 12

Degree of shrinkage depends on material common 10-15%

Answer 12

true

Question 13

example page 28

Answer 13

true

Question 14

Mass diagram

Answer 14

from page 31 to 34

Question 15

Free haul distance

Answer 15

the distance over which material is moved from cut to fill without extra charges

Question 16

Over haul distance

Answer 16

when it is necessary to transport material for a distance greater than the free haul distance implies we will have additional charges.

Question 17

Overhaul distance

Answer 17

material transport distance minus free haul distance

Question 18

Borrow

Answer 18

material taken from outside the project

Question 19

waste

Answer 19

excavated material not used in the project

Question 20

length of economical haul

Answer 20

– The maximum distance beyond which it becomes more
economical to waste material excavated and borrow
material (fill) from a borrow pit instead of transporting
material within project

Question 21

There is example page 38

Answer 21

solve it