Application of Ring Column Groups to Pier
Scour Prevention
D9731312 D9731223 D9731257
I ePaper (2012 )
II ePaper (2012 )
2009 (V /Vc=0.95) b L / =1 2 3 4 5 6 b D / = 0.8 0.9 1 b H / =1.08 1.6 2.4 3 (D=b) (H/b > 2.4) 5 L=5b
III ePaper (2012 )
Abstract
Heavy rainfall frequently occurs in the summer in Taiwan due to the effects of the stationary fronts and typhoons. In recent years, the climatic anomalies tend to induce more extreme weather.For example, record-breaking heavy rainfall induced by Typhoon Morakot (2009) caused an unprecedented disaster in Taiwan. High flow caused scouring of the river bed around the piers, resulting in the exposure of the pier foundation and threatening the safety of bridge. To protect the bridge foundation,theuse of Ring column groups as a pier scour countermeasure is reported. In this study, hydraulic model experiments with Ring column groups are carried out to search for the ideal arrangements to reduce the bridge scour. It can be served as a reference of design for relevant engineers in future.
A series of experiment was conducted with uniform sediments under the steady flow (V/Vc =0.95) First for six kinds of distance(L/b=1 2 3 4 5 6)Conducted to discuss the protective effect of pier and elect the best protective effect of distance,and then use the best distance analys is four different diameters(D/b=0.8 0.9 1 three different heights(H/b=1.08 1.6 2.4 3 to the impact of the bridge pier protection .Investigate the The ring columns consisting of cylindrical rubber rings Obscured the vertical and horizontal flow of the bridge pier upstream to reduce the impact of the bridge pier scour depth.
Based on experimental results, when the diameter of the ring columns is equal to the pier diameter(D=b), the ring columns could disperse the transverse flow when the Ring column groups settings at a distance of 5 times the pier diameter, the height of the ring column is higher than the water surface(H/b>2.4).to avoid the overflow of water from the top of the ring columns,stabilize the pier upstream flow so that
IV ePaper (2012 )
water from the pier two side diversion to avoid the water concentration, when the Ring column groups settings at a distance of 6 times the pier diameter L=5b ,Can be measured to a minimum scour depth, which is the best set type among the experimental conditions.
V ePaper (2012 ) I II abstract III V VIII IX X XI 1 1.1 1 1.2 2 1.3 3 4 2.1 4 2.1.1 5 2.2 6 2.3 7 2.3.1 7 2.3.2 8 2.4 13 2.5 15 2.6 16 2.6.1 19
VI ePaper (2012 ) 21 3.1 21 3.1.1 21 3.1.2 22 3.1.3 23 3.2 24 3.2.1 24 3.2.2 25 3.2.3 26 3.2.4 26 3.2.5 26 3.2.6 27 3.3 28 3.3.1 29 3.3.2 30 3.4 30 3.4.1 30 3.4.2 30 3.4.3 30 3.4.4 31 33 4.1 33 4.1.1 33 4.1.2 34 4.1.3 35
VII ePaper (2012 ) 4.2 36 4.2.1 36 4.2.2 37 4.2.3 37 4.3 38 4.3.1 38 4.3.2 39 4.3.3 40 41 5.1 41 5.2 42 43
IX ePaper (2012 ) 3-1 29 4-1 35 4-2 38 4-3 40
XI ePaper (2012 ) 2-1 5 2-2 7 2-3 10 2-4 11 2-5 12 2-6 14 2-7 17 2-8 17 2-9 18 2-10 19 3-1 22 3-2 25 3-3 V 25 3-4 27 3-5 28 3-6 32 4-1 34 4-2 35 4-3 36 4-4 37 4-5 39 4-6 40
XIII ePaper (2012 ) 3-1 23 3-2 23 3-3 24 3-4 24
XIV ePaper (2012 ) a L2 B 缘 b 缘 d 缘 50 d 缘 缘 缘 min s d 缘 D 缘 Fr (Froude number) g −2 LT m g LT−2 LT−2
XV ePaper (2012 ) 2 g 3 g G −2 MLT h 缘 H 缘 L−1/3T D sh K . . θ K 缘 缘 缘
XVI ePaper (2012 ) Ns L−1T p −1 −2 T ML Q L3T−1 3 −1 T L 3 −1 T L 1 r S t T T T T T u x −1 LT ' u x * u −1 T L * c U −1 T L ν y LT−1 V LT−1
XVII ePaper (2012 ) −1 T L 缘 X y 缘 z 缘 α ρ −3 ML −3 ML υ 2 −1 T L µ −1 −3 T ML g σ
1 e-Theses (100 )
1.1
( ) 25002 e-Theses (100 )
1.2
( ) ( ) ( )3 e-Theses (100 )
1.3
4 e-Theses (100 )
2.1
Raudkivi(1986)[50] (1991)[4] (1) (general scour) (2) (contraction scour) (3) (local scour)Melville and Coleman(2000)[44]
5 e-Theses (100 )
(1)
(long-termgeneral scour) (short-term general scour)
(2) 2-1 2.1.1 Einstein Meyer-Peter Laursen(1962)[37] ( ) ( ) ( )
6 e-Theses (100 ) ( )
2.2
Laursen(1963)[38] ) ( ) ( ) ( S g B g dt B df − = (2-1) ) (B f dt g( B) g( S) ( ) g( B) = g( S) = 0 ( ) g( B) > g( S) ≅0 ( ) g( B) > g( S) > 0 ) ( B g = g( S) > 07 e-Theses (100 ) 2-2 V c V Va σg b 2-2
2.3
2.3.18 e-Theses (100 ) ( ) (
b
) (Ksh ) (a) ( ) (ρ ) (ν ) (V ) (y) (g) ( ) (d50 ) (σg) (ρg) (VC) ( ) (T ) (Te) 2.3.2 ( ) Flow Intensity V /Vc 1 /Vc < V [V − (Va −Vc)/Vc <1] < g σ 1.3-1.5 1 /Vc > V g σ >1.3 c V V / >1 V /Va <1 ( ) Flow Shallowness y /b y /b9 e-Theses (100 ) Neill(1964)[46] 7 . 0 5 . 1 = y b y ds (2-2) S d y b
Jain & Fischer(1981) [36]
( )
1 1 1 1 1 1 p r n m s b y B Fr b y A y d − + = (2-3) 1 A B1 m1 n1 p1 r1 r F Melville & Sutherland(1988) [41] y /b >1.43 b y / < 0.2 0.2≤ y /b ≤1.43Raudkivi & Ettema(1983) [49] y/b>3~4 Melville(1997) [39] y /b >1.5 ~ 2 ( ) Sediment Coarseness d /50 b 50 d < 0.6mm
10 e-Theses (100 )
Raudkivi & Ettema(1977)[48] d50 /b < 0.02mm
b
d50 / > 0.02mm
b
d50 / d50 /b
Raudkivi & Ettem(1983)[49]
(1) ≥ 50 / d b 130 (2) 130>b/ d50 ≥ 30 (3) 30 > b/ d50 ≥8 (4) b/ d50 ≥20 ~ 25 2-3 b/ d50 ≥ 20 ~ 25 2-3
Melville & Chiew(1999)[43]
50
/ d
11 e-Theses (100 ) 2-4 ( ) Sediment Nonuniformity
σ
g Ettema(1980) [31] Chiew(1984) [25] Baker(1986)Raudkivi & Ettema(1977) [48]
g
σ
0.3 ~ 2.3 σ g > 1.3 se d( )
b
d
K
b
d
se g se σσ
=
（2-4）coarse sediment fine sediment
~50 dse/b ds= f (d50/b) b/d50 50 ( ) s d ≠ f d b
12 e-Theses (100 ) se d
(
σ g ≅1.0)
b σ K 2-5 2-5Raudkivi & Ettema(1983)[49] σ g 1
1.4~1.5 2 * * 50 1 ln K b u V b T u b d K b d s + = (2-5) 1 K K2 ( ) T /Te T Te
Melville & Chiew(1999)[43]
13 e-Theses (100 ) 10 50 80 24 0.05 1 /Vc < V
Melville & Chiew(1999) [43]
24 5 ( ) Froude Number Ettema et al.(1998) [32] n se Fr y d ∝ Fr y Bozkus & Yildiz(2004) [20]
b
se
d Fr
2.4
14 e-Theses (100 ) 2-6 2-6 ( ) Surface Roller
StagnationPoint Stagnation Streamline Bow Wave ( ) Downflow Bernoulli Equation ElevationHead Stagnation Pressure Velocity
Head Pressure Head
Elevation Head
15 e-Theses (100 ) Vertical Jet ( ) Horseshoe Vortex ( ) Wake Vortex Separation Point Cast-offVortex
2.5
( ) Armoring Phenomena
16 e-Theses (100 )
( )
( )
SacrificialPiles Collars Iowa
Vanes 2002
Cheng-Kung Artificial Waterweeds 2004
2.6
( 2-7 )
17 e-Theses (100 )
2-7
18 e-Theses (100 )
2-9
( 2-10
19 e-Theses (100 ) 2-10 2.6.1 (1) bow wave downflow horseshoe vortex wake vortex river bed flow
Ring columns pier
water surface
20 e-Theses (100 ) (2) (3) (4) (5)
21 e-Theses (100 )
3.1
3.1.1 3-1 ( ) 13.6m 0.5 m 0.75m (tailwater gate) ( ) 15HP(Horse Power) ( )
22 e-Theses (100 )
(a) (plan view)
(b) (side view) 3-1 3.1.2 0 .7 5 m 60 V 閘 閥 尾 水 池 動 床 0.5m 13.6m 斜 升 坡 15HP 8m 尾 水 池
23 e-Theses (100 ) 1/10 5 (acrylic) 3.1.3 (1) ( 3-1): 1m 0.6 (2) ( 3-2) (3) ( 3-3) (4) ( 3-4) 0~12000 (5) (6) (7) 1.8 1.2 0.6 (8) 5 2 3-1 3-2
24 e-Theses (100 ) 3-3 3-4
3.2
(1) (2) (3) (4) 3.2.1 35cm #20 #30 #40 50 d 0.62mm σg 1.29 3-2
25 e-Theses (100 ) 3-2 3.2.2 V V 3-3 3-1 Q=0.00004y2-0.0003y+0.001 (3-1) Q= (cms) y=V (cm) 0 4 8 12 16 0 0.001 0.002 0.003 0.004 0.005 0.006 3-3 V
26 e-Theses (100 ) 3.2.3 ( ) 1m ( ) y d50 Vc c c u V * =5.75× log 50 53 . 5 d y (3-2) 1 50 5 . 0 50 * 4 . 1 50 * 0065 . 0 0305 . 0 0125 . 0 00115 . 0 − − = + = d d u d u c c mm d mm mm d mm 100 1 1 1 . 0 50 50 < < < < ( ) V c V (V /Vc) Vc (V /Vc) ( ) 3.2.4
Melville & Sutherland(1988)[41]
b y / >1.43 1.5 1/10 5 8 3.2.5 ( L=45 cm) 16 40 2.5 mm 5% Melville(1999) [43] 40
27 e-Theses (100 ) 3-4 10 90.41 8 8 3-4 3.2.6 (fully development) ( ) ( ) ( ) ( )
28 e-Theses (100 ) V Vc V /Vc 0.95 8 7.00m ~9.30m 8.5m 3-5 3-5
3.3
1 2 3 3-1
29 e-Theses (100 ) 3-1 (L/b) (D/b) (H/b) A1 B1 1 1 3 B2 2 1 3 B3 3 1 3 B4 4 1 3 B5 5 1 3 B6 6 1 3 C1 5 1 3 C2 5 0.9 3 C3 5 0.8 3 D1 5 1 3 D2 5 1 2.4 D3 5 1 1.6 D4 5 1 1.08 3.3.1 ( ) ( ) ( ) ( ) ( )
30 e-Theses (100 ) ( ) 3.3.2
3.4
3.4.1 3.4.2 V /Vc=0.95 2 8 cm 0.5 cm 3.4.3
31 e-Theses (100 ) 3.4.4 3-6 (1) (2) (3) (4) (5) Q 16 16 30 2 30 60 5 60 180 10 180 480 (6) 8 (7) (3)~(6)
32 e-Theses (100 ) Q
33 e-Theses (100 )
33 ePaper (2012 )
4.1
4.1.1 4-1 3 6.5 L/b=5 L/b=1 L/b=1 2 L/b=3 L/b=134 ePaper (2012 ) L/b=2 (0.3) (0.1) 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 0.0 0.2 0.4 0.6 0.8 1.0 d s/ b ti/t no protection L/b=1 L/b=2 L/b=3 L/b=4 L/b=5 L/b=6 4-1 4.1.2 L/b=5 L/b=6 L/b=6 L/b=5 4-2
35 ePaper (2012 ) -2.5, -0.8 -2 -1 0 1 2 -10 -5 0 5 10 15 20 z/ b L/b no protection L/b=1 L/b=2 L/b=3 L/b=4 L/b=5 L/b=6 橋 墩 4-2 4.1.3 5 (L=5b) L=6b 5 45 50 L=6b 5 5 L>6b 4-1 (L/b) ds(cm) (%) A1 6.6 D1 1 5.4 18.2 D2 2 5.7 13.6 D3 3 5.6 15.2 D4 4 6.0 9.1 D5 5 5.3 19.7 D6 6 5.8 12.1
36 ePaper (2012 )
4.2
4.2.1 4-3 6.5 3 D/b=0.8 1 4-3 D/b=1 0.9 0.8 D/b=1 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.0 0.2 0.4 0.6 0.8 1.0 d s/ b ti/t no protection D/b=1 D/b=0.9 D/b=0.8 4-337 ePaper (2012 ) 4.2.2 4-4 -2 -1 0 1 2 -10 -5 0 5 10 15 20 z/ b L/b no protection D/b=1.0 D/b=0.9 D/b=0.8 橋 墩 4-4 4.2.3 0.8 19.7 18.2 0.9 18.2
38 ePaper (2012 ) 4-1 4-2 (D/b) ds(cm) (%) A1 6.6 C3 1 5.3 19.7 C4 0.9 5.4 18.2 C5 0.8 5.4 18.2
4.3
H y 15cm 12cm 8cm 5.4cm 4.3.1 4-5 H/b<1.6 1 H/b=2.4 H/b=3 H/b=1.6 H/b=3 H/b=1.0839 ePaper (2012 ) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.0 0.2 0.4 0.6 0.8 1.0 d s/ b ti/t no protection H/b=1.08 H/b=1.6 H/b=2.4 H/b=3 4-5 4.3.2 4-6 H/b=1.08
40 ePaper (2012 ) -2 -1 0 1 2 -10 -5 0 5 10 15 20 z/ b L/b no protection H/b=1.08 H/b=1.6 H/b=2.4 H/b=3 橋 墩 4-6 4.3.3 4-3 4-3 (H/b) ds(cm) (%) A1 6.6 D1 3 5.3 19.7 D2 2.4 5.1 22.7 D3 1.6 5.9 10.6 D4 1.08 6.2 6.06
41 ePaper (2012 ) ( c V V / =0.95 y /b=1.5) ( 50 / d b =81
σ
g=1.24)5.1
1. 2. 5 (L /b=5) 19.7% b L / =4 9.1% 3. H/b>2.4 4.42 ePaper (2012 ) 5. 5 L=5b (D=b) (H>b) 19.7%
5.2
1. 2. 3. 4. 5.
44 ePaper (2012 )
1. 2002 2. 2005 3. 2004 35 151-163 4. 1991 167 184 5. 2008 6. 2003 7. 2006 8. 2007 9. 2008 10. 2009 11. 2010 12. 2006
45 ePaper (2012 ) 13. 2007 14. 2007 15. 2005 N69-73 16. 16. 2006 17. 2006 18. 1986 33 19. 2004 (2/3)
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