1992-03-02_REVISION - C1981035

• Permit No: C1981035
• IBM Index Class Name: REVISION
• Doc Date: 3/2/1992
• Doc Name: Amendment to TR 4 Mine Drainage Riprap Design for Eastside Drainage
• From: Don May
• To: DMG
• Type & Sequence: TR4
• Media Type: D
• Archive: No

RIP-RAP SIZE BASED ON STABILITY ANALYSIS
National King Coal Mine,Eastside Drainage Channel
Bank riprap design for noncritical locations,depth<= 10 fL
1 4 b 1 7 8 9 10 11 12 13 14 15 16
Manning Sb lamda,Se shea r stress angle if 9999 SF SF
d V n (ft(ft) Mitt) GdS I/8pfV2 z D50 repose z is to n B n' side (bed)
(ft) (fps) (degrs) (degrs) (I b/ft2) in (degr) big slope
0.5 8.0 0.03 0.0600 0.0000 1.87 2.01 2 0.41 21.72 0.28 1.18
3.43 0.00 2.0 14 41.0 2 0.33 17.64 0.21 1.27 2.52
0.0599 0.0000 2.0 16 41.0 2 0.29 15.55 0.18 1.32 2.81
(red) (red) 2 0.25 13.90 0.16 §W 3.09
2.0 20 41.0 2 0.23 12.55 0.14 1.39 3.35
2.0 24 41.0 45 184�J I
' o iner 10 D20 Mo MFO 1335 001 075 1 086 D90 D1
ize in 14 inch 5 7 9 11 14 16 19 21 25
ze W(in) 18 inch 7 9 12 14 18 21 24 27 32
izz-11
wt.of water G= 62.4 lb/ft3
wt.of sed. = Gs= 165.4 Ib/ft3
S.G.of sed = 2.65
**If 9999 appears the the side slope is to steep.
MODEL EXPLANATION:This riprap design model is based on the
concept Of stability theory.In short, R all the forces
acting on a particle which tend to displace it equal those
which tend to hold it in place,then the particle is in exact
equilibrium(incipient motion).At this condition the SAFETY
FACTOR is unity.In order to assure a stable riprap size the
design SF should be at least 1.5.Specific equations and
theory can be found in the accompanying documentation or in
'Sediment Transport Technology',by D.B.Simons and F.Senturk,
1977.
COLUMN EXPLANATION:
C1-05 are hydraulic data from HEC-2 or similar model.
• depth(d) and bed slope(Sb) are used to compute the shear
stress in C6.
• roughness(n) and velocity(V) are used to compute the
shear stress in C7.
the model uses the larger shear stresses,C6 or C7.
C8 z is the bank side slope as z horz.to 1 vert.,ZA.
C9-C1 0 are the trial median riprap size and the associated
angle of repose,which must be looked up and input here.
C11 is a check on the compatibility of the chosen side slope
and the following limiting conditions:the side slope
be less than the angle of repose minus 5 degrees and not
greater than 2:1.
z and 050 are the design variables.Adjust these until an
acceptable SAFETY FACTOR is attained.
C1 2-Cl 5 are the design equations which use the previously
generated data.C12 uses the larger of the shear stresses
from C6 and C7.
ALL UNITS ARE IN ENGLISH SYSTEM(FT,LBS,SEC),except
for 050 which is in inches.