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This document summarizes the hydraulic design and stability analysis of Storm Water Drain 5B for the Kannur International Airport construction project. It analyzes two sections of Drain 5B from chainage 0 to 287 meters and chainage 287 to 520 meters. For both sections, it calculates the discharge, velocity, bed slope, and other hydraulic parameters to ensure the drain can safely pass 3.6 cubic meters of water per second. It also performs stability calculations to verify the retaining wall has sufficient safety factors against overturning and sliding. The analysis considers two different soil types, with slightly different parameters and safety factors for the last 50 meters containing clay soil.

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58 views6 pages

AL de Fil

This document summarizes the hydraulic design and stability analysis of Storm Water Drain 5B for the Kannur International Airport construction project. It analyzes two sections of Drain 5B from chainage 0 to 287 meters and chainage 287 to 520 meters. For both sections, it calculates the discharge, velocity, bed slope, and other hydraulic parameters to ensure the drain can safely pass 3.6 cubic meters of water per second. It also performs stability calculations to verify the retaining wall has sufficient safety factors against overturning and sliding. The analysis considers two different soil types, with slightly different parameters and safety factors for the last 50 meters containing clay soil.

Uploaded by

nidhisasidharan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as XLSX, PDF, TXT or read online on Scribd
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KIAL -Construction of storm water drain beyond the boundary of Kannur International Airport

Hydraulic Design of Storm water drains- Drain 5B from chainage 0.0 to 287 m

Drain 5B (Ch 0 to 287 m) Q= 3.6 cumecs


1.45 m

0.7 m

1.25 m

Length of drain= 287 m


RL at entry point = + 96.88 m
RL at exit point = + 86.31 m
Bed slope=(96.88-86.31)/287=10.57/280.0368
=1/0.0368= 27.174

Adopt Bed slope= 1 in 35


Velocity is limited to 6m/s
n= 0.016 (Rugosity coefficient)
Check for discharge
A= ((1.25+1.45) /2*)0.7
= 0.945 m2
incli length 0.707 m
P= 1.25+2*0.707
= 2.664 m
R=A/P= 0.355
V=(1/n)R2/3 S1/2
V=(1/n)*(0.355^(2/3))*1/35^(1/2)
= 5.3 m/s
Q=AV= 0.945*5.3 = 5.01 m3/s
> 3.6 m3/s
The velocity obtained is high, but the velocity might reduce due to the bends in the canal stretch .
Bed slope 1 in 35 is required to pass 3.6 cumecs discharge and also to keep velocity within 6 m/s
As there is an existing culvert at the end of the stretch, drops may be provided at
suitable locations to maintain the level at the culvert.
STABILITY ANALYSIS OF THE SIDE WALL OF THE DRAIN 5 B (Ch 0 to 287 m)
Condition :- No water in the canal and backfill saturated

0.3

water 0.9 Φ= 35 Gravel


0.7 earth sinΦ= 0.573
ka = (1-sinΦ)/(1+sinΦ) = 0.271
0.4
0.271*2.1*1/2*0.9*0.9
Lateral earthpressure=1/2 *(Ka ϒsat h) 0.23
=

V (t) H (t) LA (m) MR Mo


Wt of C.C wall body ϒconcrete=2.5t/m3
0.3 0.9 2.5 0.675 0.250 0.169
0.1 0.7 2.5 0.088 0.067 0.006
Lateral earth pressure 0.230 0.300 0.069
Total 0.763 0.230 0.175 0.069

F.S (Overturning)= 0.175/0.069 2.536 > 2 Hence ok


F.S (sliding)= 0.7*0.763/0.23 2.322 >or = 1.5 Hence safe
KIAL -Construction of storm water drain beyond the boundary of Kannur International Airport
Hydraulic Design of Storm water drains- Drain 5B from chainage 287 to 520 m

Drain 5B (Ch 287 to 520 m)


Q = 3.66 cumecs
1.45

0.7

1.25

Length of drain= 233 m


RL at entry point = + 86.31 m
RL at exit point = + 83.44 m
Bed slope=(86.31-83.44)/233=2.87/233= 0.012
=1/0.012=83.333
Adopted Bed slope= 1 in 60
Where Max. velocity is 6m/s
n= 0.016 (Rugosity coefficient)
Check for discharge
A= ((1.25+1.45) /2*)0.7
= 0.945 m2
incli length= 0.707 m
P= 1.25+2*0.707
= 2.664 m
R=A/P= 0.355
V=(1/n)R2/3 S1/2
V=(1/n)*(0.355^(2/3))*1/60^(1/2)
= 4.048 m/s
Q=AV= 0.945*4.048= 3.825 m3/s
> 3.6 m3/s
Bed slope 1 in 60 is required to pass 3.6 cumecs discharge and also to keep velocity within 6 m/s
Ascertain that the end level of drain must be above the bed level of Karathodu for safe discharge of
storm water
STABILITY ANALYSIS OF THE SIDE WALL OF THE DRAIN (Ch 287 to 520 m)
Condition :- No water in the canal and backfill saturated
0.3

water 0.9
0.7 earth
Φ= 35 Gravel
A 0.4 sinΦ= 0.573
ka=(1-sinΦ)/(1+sinΦ) = 0.271
Lateral earth pressure=1/2 *(Ka ϒsat h)* h= 0.271*2.1*1/2*0.9*0.9= 0.23

V (t) H (t) LA (m) MR Mo


Wt of C.C wall body ϒconcrete=2.5t/m3
0.3 0.9 2.5 0.675 0.250 0.169
0.1 0.7 2.5 0.088 0.067 0.006
Lateral earth pressure 0.230 0.300 0.069
Total 0.763 0.230 0.175 0.069

F.S (Overturning)= 0.175/0.069 2.536 > 2 Hence ok


F.S (sliding)= 0.7*0.763/0.23 2.322 >or = 1.5 Hence safe

For clay at last 50 m Φ= 28


sinΦ= 0.469
ka = (1-sinΦ)/(1+sinΦ) = 0.361
0.361*2.1*1/2*0.9*0.9
Lateral earth pressure=1/2 *(Ka ϒsat h)* h = 0.307 t
=

V (t) H (t) LA (m) MR Mo


Wt of C.C wall body ϒconcrete=2.5t/m3
0.3 0.9 2.5 0.675 0.250 0.169
0.1 0.7 2.5 0.088 0.067 0.006
Lateral earth pressure 0.307 0.300 0.092
Total 0.763 0.307 0.175 0.092

F.S (Overturning)= 0.175/0.092 1.90 app equal to 2 Hence ok


F.S (Sliding)= 0.7*0.763/0.307 1.74 > or = 1.5 Hence safe

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