IMPLANT LEVEE Highly Resilient Disaster Prevention Levee

Levee Upgrading Work in Japan Implant Levee Embedded Resilient Structure

Twin Steel Sheet Pile Wall System Steel sheet piles are installed into the embankment to a depth determined for proper stability and/or cut-off of flow. Also, liquefaction of the levee can be prevented by enclosing it with twin sheet pile walls. Thus, the levee can withstand large external loading and the levee crest can remain in place, even in catastrophic events.

■ Advantages of Implant Levee

Flood, Storm Surge and Tsunami Protection Functions of the levee can be main- tained by increasing its stability. Tie Rods Current Embankment

Local Failure due to Turn Back Waves

Steel Sheet Pile Wall

Liquefaction Protection Functions of the levee can be main- tained by the ground enclosure effect.

Settlement Contiguous Steel tubular pile wall is a vertical barrier and can be installed in locations where space is Tubular Pile Wall scarce, such as urban environments or where the construction of a wide levee is not feasible. The piles are installed into the embankment to a depth determined for proper stability to with- Potentially Liquefiable Soil Layer stand largegy dynamic and hydraulic loading. Anti-liquefaction Ground Gyropress Method Press-in Force Gyropress Method installs tubular piles Giken Reaction Base (GRB) System with cutting bits attached on pile toe by The press-in machine utilises reac- Gyration Force rotary jack-in system, and travels on top tion force from previously installed Piling Direction of piles which are completely installed piles and performs piling work on top Pile (completed piles). of the piles. With further development based on the principle of "reaction Silent Piler Power Unit Clamp Crane Gyropress (Presses-in Pile) (Power Source) (Pitches Pile) Force Gyropress Method allows the installation based mechanism", "the GRB of tubular piles without prior removal of System" was developed as a existing structures and/or obstacles. press-in system which performs all piling procedures such as; pile trans- portation, pile pitching and press-in work, on top of installed piles. The GRB System consists of a Silent Piler in the front, a Power Unit as a Pile Runner (Conveys Piles) Reaction power source, a Clamp Crane to Unit Runner Force Piler Stage (Conveys Power Unit) pitch piles and a Pile Runner to (Work Platform) convey piles from storage site.

1 2 Comparison of Implant Levee to conventional levees (Risk Analysis)

Failure of levees potentially results in devastating consequences, in both life and economic losses, around the failure. Therefore, risk analysis and evaluation is a key issue for levee operation and management. Risk Evaluation

Failure/ Deterioration Mode/ Risk Elements Process Implant Levee Conventional Levee

Animal Burrowing Instability Water entering the embankment through Shrinkage Cracks surface cracks or animal burrows could reduce (Desiccation Cracks) the soil strength of the levee.This may compromise the stability of the embankment Negligible Moderate - High and, in turn, reduce the ability of the levee to perform as designed during high water events.

Seepage Internal Erosion The hydrostatic pressure against a levee slope Suffusion increases significantly and can force water into the levee embankment and its foundation. This seepage will generally follow paths of least Negligible Moderate - High resistance. Depending on the geotechnical properties of the soil, internal erosion may then happen.

Liquefaction Settlement Large seismic accelerations cause settlement Age Effect and loss of effective shear strength in Lateral water-saturated, unconsolidated sediment, Spreading Settlement leading to loss of bearing pressures and lateral Negligible - Low High spreading of levee.

Liquefaction

Flood Breach Levees can breach before overflow/ overtopping Tidal Action if there are structural issues with the levee River Flows making it unstable under a hydraulic load. Negligible Moderate - High

(Widespread Devastation) Collapse Large external cyclic loading due to these catastrophic events may lead to large parts of the levee collapsing or significant deformations. Flood The levee failure occurs when the weakness of Negligible - Low High Storm Surge the levee reaches an unsustainable ultimate Seismic Loading state. Tsunami Strike

3 4 Costal Levee Upgrading Work, Japan

Twin Sheet Pile Walls installed with Press-in with Simultaneous Augering 【Plan】 2,399no. U Sheet Piles Ⅳw L=15.0m - 16.5m (700Lm)

Sheet Pile Installation

Land Side Twin Sheet Pile Walls Tie Rods

Sea Side

Sheet Pile Installation Tie Rod Installation

【Cross Section】 Silent Piler (Crush Mode) Land Side Sea Side Tie Rods

Completion Completion

Road

Scour Protection

Fill

Boulders φ500mm-800mm 5000mm ～ 6000mm

Potentially Liquefiable Soil Layer U Sheet Piles Ⅳw L=15.0 m ～ 16.5 m Sheet Piles Sheet Piles (Land Side) (Sea Side)

5 6 Seawall Upgrading Work, Japan

West Area Contiguous Tubular Pile Wall installed with Gyropress Method (Rotary Jack-in Method) 564no. Tubular Piles φ1,000mm L=19.5m (670Lm) Pile Installation without disturbing adjacent traffic Pile Installation (Gyropress Method) (Gyropress Method)

Post Pile Installation

East Area Twin Sheet Pile Walls installed with Press-in with Simultaneous Augering 1,800no. U Sheet Piles Ⅲw L=19.5m - 23.0m (577Lm)

【Cross Section】【Cross Section】 New Seawall Rapid Construction by Systematic Method

Sea Side Land Side Sea Side Land Side

Road Tie Rods

New Seawall Existing Seawall 盛土(中詰) Existing Seawall Concrete Liner Wall

Road

構造物取壊し

Wall Section 鋼矢板Ⅲw 型 L=19.5 ～ 23.0

Tubular Piles φ1,000mm 6500ｍｍ U Sheet Piles Ⅲw L=19.5m L=19.5 ～ 23.0m

7 8 Other Examples

■ Seawall Upgrading Work, Japan（ Gyropress Method) ■ Riverine Levee Upgrading Work, Japan

Cross Section Cross Section 【】 Tubular Pile Installation 【】 Sea Side Land Side Leveed Area Foreland

Fill Sheet Piles Tubular Piles φ1,300mm Post Pile Installation Scour Protection L=27.5m

Potentially Liquefiable Soil Layer

Tubular Piles φ900mm L=19.0m

Anti-liquefaction Ground

■ Levee Upgrading Work, Japan ■ Seawall Improvement Work, Japan

【Cross Section】【Cross Section】 Sheet Pile Installation

Sea Side Land Side Land Side Sea Side

Tie Rods

Post Pile Installation

U Sheet Piles Ⅲw, ⅤL and ⅥL 4000ｍｍ Tubular Piles L=15.5 ～ 17.5m φ1,000mm L=13.5m ～ 20.5m Potentially Liquefiable Soil Layer

Anti-liquefaction Ground

9 10 Construction Solutions Company www.giken.com/en Levee Upgrading Work in Japan GIKEN LTD. Global Network : Japan, USA, UK, Germany, Singapore, China Construction Design & Planning Group 1-3-28 Ariake, Koto-ku, Tokyo 135-0063, Japan Tel. : +81-(0)3-3528-2633 Fax : +81-(0)3-3527-6055 Email : [email protected]