3/3/2011

12th CPDAC meeting 3 Mar 2011 in Bhubaneshwar By Prof. V. Sundar Department of Ocean Engineering Indian Institute of Technology Madras Chennai, INDIA

Interaction of Tsunami with vegetation

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 2 e‐mail: [email protected]

1 3/3/2011

Is it role of vegetation? Tsunami Heights =3-=3-4m4m

Department of Ocean Engineering, Indian Institute of Technology Madras 3 3 Chennai, INDIA 600036..e‐mail:[email protected]

Greenbelt Parameters Dt BG

D

SP

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 4 e‐mail: [email protected]

2 3/3/2011

BG=0.25m:D=1.65mm:SP=37.5mm(RE) BG=0.25m:D=1.65mm:SP=37.5mm(RE) BG=0.25m:D=5.5mm:SP=37.5mm(RE)

BG=0.625m:D=5.5mm:SP=75mm(ZG)

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 5 e‐mail: [email protected]

4 SP/Dt=3.75 3.5 Reduced SP/Dt=3.75 Velocity, Vr SP/Dt=7.5 (V/fD)~4.0 SP/Dt=12.5 3 SP/Dt=25 SP/Dt>3.75 2.5

2 Darcy's 'f' Darcy's

1.5

1

0.5 SP/D ~3.75: Proximity Effect Predominant Vr~4.0: Wake Effect Predominant 0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Froude Number

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 6 e‐mail: [email protected]

3 3/3/2011

Utility of the newly proposed Relative Rigidity A Design Example

Properties Oak tree[Light] Casurina[Medium] Mangrove[Heavy] E 9Gpa 14Gpa 18.5Gpa

Dt 0.267 m0.267 m0.267 m

λ 111

f1 0.3037 0.37 0.43

Vr 51.9 41.6 36.2

SP/Dt 6 6 6

RR 3.87 4.02 3.98

Design BG 120 m80 m60 m

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 7 e‐mail: [email protected]

Characteristics of an ideal seawall are

‰Less reflection and Run‐up Over ttiopping Energy dissipation ‰Optimum use of coastal space is prevented 1 through turbulance ‰Less or no wave overtopping and resulting eddies 2 ‰Lower crest elevation ‰Less maintenance costs

3 Strong toe protection

This objective may be achieved by considering a front shape of the structure, which forms the main objective of the present study.

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 8 e‐mail: [email protected]

4 3/3/2011

It is evident that a seawall as a coastal protection measure should be effective with an optimum use of the coastal space, with less or no wave overtopping by maintaining a lower crest elevation.

This in fact can also enhance the scenic beauty of the oceanic view.

Hydrodynamic characteristics of different shapes of Seawalls

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 9 e‐mail: [email protected]

0.37

39°0' R0.59 0.37 0.40 R1.61 25°21' 0.81 0.81

0.44 0.71 Supporting structure for the 1.05 0.37 0.56 0.13 seawalls to stand on MODEL - (VW) MODEL - (GS) 0.37 R0.61 0.04 R0.56 0.29 0.21 R0.51 R0.20 0.81 R0.46 0.81 0.81 Y = X²-10X+25 R0.41 0.56

R0.36 R0.31 R0.26 0.73 0.32 R0.20 0.17 0.69 40% of 0.20 MODEL - (FSS) structure MODEL - (CPS) Models fixed in the flume Model (VW) Vertical wall height Model-(GS) Galveston seawall, (Coastal Engineering Manual, 2006) Model-(FSS) Flaring shaped seawall, (Kamikubo, et al., 2000) Model- (CPS) Circular cum parabolic seawall , (Weber, 1934)

1 : 30 slope with partition Model fixed over the slope Pressure transducer 10

5 3/3/2011

Various configurations of seawall tested and compared

Run‐up 1 Dynamic Pressure 2 Reflection 3 LOW / GOOD HIGH / POOR OOtvertoppi ng 4

1 2 3 4 1 2 3 4

1 2 3 4 1 2 3 4

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 11 e‐mail: [email protected]

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 12 e‐mail: [email protected]

6 3/3/2011

Cubes Cubes Tetrapods(trunk) Accropods

Tetrapods (head) Dolos (trunk) Dolos (head) Core‐Loc

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, 13 e‐mail: [email protected]

 KOLOS – MdifidModified version of DOLOS armour units.

– Re‐designed the DOLOS units by reducing the distance between the vertical arms

– Reduced susceptibility to fail at the junction of the horizontal and vertical arm due to wave action.

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, e‐mail: [email protected]

7 3/3/2011

E

C

S E S1 C S1

S S

B

VIEW A VIEW C VIEW C

WEIGHT (tonnes)128542 VOLUME (m3) 5.0 3.33 2.083 1.667 0.833 A (m) 0.659 0.576 0.493 0.457 0.363 B (m) 1.055 0.922 0.789 0.732 0.581 C (m) 3.297 2.881 2.465 2.287 1.816 D (m) 0.188 0.164 0.141 0.130 0.104 E (m) 2.473 2.161 1.849 1.715 1.362 S (m) 0.439 0.383 0.328 0.304 0.242 S1 (m) 0.274 0.239 0.205 0.190 0.151

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, e‐mail: [email protected]

Breakwater sections with trunk slopes 1 in Breakwater heads section with slope 1.5, 1in 2 and 1 in 2.5 armoured with KOLOS 1 in 1.5 armoured with KOLOS

Hudson’ s stability coefficient for trunk (KD) Hudson’ s stability coefficient for head (KD) Trunk Upto 0.5% Upto 1% Trunk Slope Upto 0.5% Upto 1% damage Slope Zero Damage Zero Damage Damage damage Damage 1 in 1.52332351 in 1.5 6.5 8 ‐ 1 in 2.0 19.5 27 ‐ 1 in 2.0 4.5 5 ‐ 1 in 2.5 14 23 ‐ 1 in 2.5 3 3.5 ‐

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, e‐mail: [email protected]

8 3/3/2011

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, e‐mail: [email protected]

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, INDIA 600036, e‐mail: [email protected]

9 3/3/2011

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 19 INDIA 600036, Tel.: 91‐044 ‐ 22578622; e‐ mail:[email protected]

Southern Offshore Approach Groin Breakwater Trestle

Inlet Submarine channel Northern Tunnel GiGroin

10 3/3/2011

BEFORE SAND BYPASSING January 2002

AFTER SAND BYPASSING BEACH WON October 2002

A VIEW OF SHORELINE NEAR GANDHI STATUE

A VIEW ON NORTH SIDE OF GANDHI STATUE (BEFORE SAND BYPASSING) January 2002

FORMATION OF BEACH ON NORTH SIDE OF GANDHI STATUE (AFTER SAND BYPASSING) October 2002

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BEFORE SAND BYPASSING January 2002

AFTER SAND BYPASSING October 2002

A VIEW OF SHORELINE NEAR NORTH SIDE OF JETTY

The erosion and accretion is estimated Erosion from 1986 to 2002, i.e., over a period of 16 years with the satellite imagery data using GIS software. The rate of erosion is about 4m per year and the accretion is 6m per year. The extent of erosion in the northern Accretion side is 33.59 hectares compared to the accretion on southern side of 30.71 hectares..

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GEO‐SYNTHETICS

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 25 INDIA 600036, Tel.: 91‐044 ‐ 22578622; e‐ mail:[email protected]

GEO-Tubes

Cross‐section showing installation of the Mirafi ® Geotube ® in a typical sand dune

13 3/3/2011

Filling operation of the Mirafi ® Geotube ® : Fill Material is pumped into the tube, displacing the water. Typical water/sand ratio during pumping is 90% water, 10% sand

GEO-BAGS protection for Island of Sylt, Germany

14 3/3/2011

Location map of the site WEST BENGAL

STATUS OF THE COAST in mid 2007

Dhiga beach‐ view towards east of SeaHawk hotel Usage of Ballas on the western side of the coast near the road near Chandpur

High tide penetration into the sand dunes

Usage of Ballas on the eastern side of the coast near the road near Chandpur

15 3/3/2011

Initial section considered

(+) 9.69 M

SEA FACE

EXISTING SAND DUNE

FILLED WITH LOCAL SAND

UV STABILIZED GEOTEXTILE 9mm‐4 STRAND TARRED PP ROPE TUBULAR GABION (+) 5.17 M GEOTEXTILE TUBE FILLED WITH SAND (+) 4.90 M GEOMAT

WOVEN GEOTEXTILE GEO CONTAINER GWF 26-130 2 M x 1.50 M x 1 M

GEO BAGS OF 0.50 M x 0.50 M

(+) 2.00 M BEACH PROFILE (+) 2.00 M (+) 1.70 M

(+) 0.70 M

4.40 4.40 2.50

HEXAGONAL DOUBLE TWISTED NET

WOVEN GEOTEXTILE GWF 26-130

Completed Structure

Revised section adopted

16 3/3/2011

Status prior to protection

Completed portion of the protection

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 34 INDIA 600036, Tel.: 91‐044 ‐ 22578622; e‐ mail:[email protected]

17 3/3/2011

SHAR Inlet –Opened condition 13°50'2.71"N 14/Feb/09

13°48'13.07"N Offshore structures 35

MORPHOLOGICAL CHANGES AT SHAR INLET ( 1990 – 2007)

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18 3/3/2011

Inlet Management at SHAR inlet

A pilot project aims at assessing

1. Functional 2. Structural

NIOT

IIT, Dept of Ocean Engg IIT, Dept of Civil Engg

9Analysis of morphological changes

9Field investigations

9Numerical Modelling

9Design of Geotextile based training jetties

9Implementation and post monitoring

37

¾ ¾ Selection and specification of geo-synthetic properties for various applications (revetments, shore protection, breakwaters, geo-systems, etc.) ¾ ¾ Influence of fill-ratio on performance on design and performance of geo- systems ¾ ¾ Influence of fill material on performance (sand, mud, silt materials, clay, coarse materials, saturated, unsaturated, etc.) ¾ ¾ Hydraulic interactions; reflection, transmission, permeability, roughness ¾ ¾ (More) Uniformity in stability formulations and limits of application in various applications (on slope, offshore, submerged, emerged, singular, stacked, etc.)) ¾ ¾ Internal (in-)stability of system (internal migration) ¾ ¾ Scour prediction and protection ¾ ¾ Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 38 INDIA 600036, Tel.: 91‐044 ‐ 22578622; e‐ mail:[email protected]

19 3/3/2011

¾ Stimulating research in field of geo-systems

¾ Clear definition of applicability of woven and non-woven materials and proper guidelines ¾ ¾ Durability of geo-synthetics and geo-systems for tropical weather conditions ¾ ¾ Accuracy of placement of geo-systems ¾ ¾ Review of construction techniques (uniform pumping geo-tubes, anchoring, filling and releasing geo-containers-stacking units, etc.) ¾ ¾ Techniques for the removal of damaged units. ¾ ¾ Construction specifications ¾ ¾ Quality control (strength of seams and length effect) ¾ ¾ Cost effectiveness of geo-systems compared to conventional structures ¾ ¾ Monitoring techniques ¾ ¾ Involving clients in research and systematic monitoring ¾ ¾ Preparing (and regular updating) of design guidelines ¾ ¾ Improving exchange of knowledge (forming of working groups within IAHR or similar organisations) ¾ Department of Ocean Engineering, Indian ¾ Organizing a forum/platformInstitute offor Technology contacts Madras, and exchange Chennai, of information 39 ¾ (how to avoid INDIAconfidentiality 600036, Tel.: ?) 91‐044 ‐ 22578622; e‐ mail:[email protected]

THANKS FOR YOUR KIND ATTENTION

Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 40 INDIA 600036, Tel.: 91‐044 ‐ 22578622; e‐ mail:[email protected]

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