Rock Chute

1
Rock Chute Mike Cox State Conservation Engineer
Contractor Certification Training March 2008
2
Grade Stabilization Structure (410)

• Purpose Stabilize the grade and control erosion
  in channels. Prevent the formation or advance of
  gullies.

• Rock Chutes are commonly used to control grade in
  Indiana

3

• Rock Chute-Advantages
• Most of the construction can be done with a
  backhoe or excavator
• Economical compared with poured concrete

4

• Rock Chute - Disadvantages
• Rock can move during large storms
• Hard to find larger rock sizes in certain areas
• High overfalls require long chutes
• Small rock size increases width and length of
  chute

5

• Rock Size vs Velocity

6

• What is a d50?
• Expressed as D50 size (50 maximum passing by
  weight)

7
Example p1 24 p2 19.2 D50 (24
19.2)/8 5.4 inches
8

• Bedding
• Minimum Thickness 6
• INDOT Sizes Specified

9

• Geotextile

10

• Riprap Thickness
• Minimum of 1 thickness
• Must be 2 times D50 size
• Example
• If using D50 Size 7 Riprap
• Minimum Riprap Thickness 2 7 14

2xD50 min.
11
Installation Report http//www.in.nrcs.usda.gov/t
echnical/engineering/engineering.html
12
(No Transcript)
13

14
Helping People Help the Land