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b. Structures and execution statement of canal section reiforced

b. Structures and execution statement of canal section reiforced

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machine in about 20m central line of canal to avoid untablize

stone masonry at foot of slope .

* Precast-concrete carpet PDTac-M solution

Description

- PDTAC-M carpet is a kind concrete carpet that automatic

chocking with using a steel net, this one used to protect

for building with flooded bank, they are precast

reinforcement concrete, front surface is hexagonal in

shape, behind surface there are 3 automatic chocking

foots which is hooked, fixed on available steel net. Carpet

pices joined nearly with automatic link in 3 directions and

defending voids to prevent absorbent water flow in bank

running out that damage to stability of slope.

- With this structure, steel net act as buffer float to against

settlement, distribute load regularly of carpet on weak

soil, limit settlement phenomenon on some points of

concrete carpet and 4 edges of one mesh set up a border

to restrain the contact among carpet tiles, the void among

carpet tiles is small, regular enough to form joints which

restrain minimize the bending force on carpet tile, and

stretch force in steel net.

- P§TAC- M precast concrete carpet there are 2 parts: Carpet

net is knitted by steel d6-d8mm to make Sin in shape,

with length from 10-80m, 2.6-3.2m width, around by

border and inner is divided by steel d12-d16mm, then

putting carpet tiles on to make a continuos carpet.

- Concrete carpet is able to up 10-80m length or longer, at

present it is able to cover all slope. the area of carpet can

be changed depending on design, and able to execute 4

carpets about 800m2 per day.

- with flat surface will be easy for running water, make

more beautiful landscaping, environment, Behind surface

is a foot system which is fixed in slope foundation that will

make strong ability in nonslip of carpet tile.

- Carpet is constructed with steel float to against settlement

and could execute in water easy by crane on float, this

automatic-concrete carpet enough stability in long term



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even when steel net dusty and break. The weight of one

carpet tile is enough to against running force of water.

- This kind of concrete carpet has been applied to execute

more than 70km to protect river banks and dykes in Long

xuyen city of An giang province/

Hereafter are some pictures expressing structures and

execution method of precast concrete carpet.



P 1: structures of P§tac-M carpet tile

Poto 2,3 : Execution method of P§TAC – M carpet



P 4: P§TAC-M embankment

-Structural description of PDTAC-M carpet

PDTAC-M carpet, there are 2 parts,

First one in water, using steel net to link carpet tiles then

spread carpet in water. Foot of carpet fixed more deeply than

canal bottom 0.5m follow slope direction, purpose of this

work ensure stablity of carpet when carrying out dredge mud

(during operation process).

Second part is one left higher than water level, capet tile will

be installed by man with purpose to make more beautiful.

Under the carpet we use filter-textile, which is designed to

prevent drifting sand of 2c,2d layer.

Carpet boards designed when jointing them in water, it is

still closely enough as engineering requirements.

At 2c layer, to keep the slope stablize, this canal part must

be executed in water and water level must always is the

highest level untill slope finishing reinforcement.

To check flat of slope, we will stick mesurement equipment

of deformation on canal section, thus Owner could supervise

quanlity of canal slope without wading in water.

Advantages of PDTAC -M carpet.

- Cheaper than stone masonry



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- Automatic chocking in 3 direction so it is able to defend

voids

- More beautiful than stone masonry

- Execution more quickly and in water but it is still ensure

engineering requirement

- More stablely and easy for reparing

There are other reiforcement method of slope as

reiforcement by FS carpet, cocrete, stone carpet, seeding ...

d. Conclution

We chose reinforcement of slope by Precast-concrete PDTACM carpet

II.1.2 Line 2: Structures and execution method of Cửa

Đình Cofferdam

The Cuadinh cofferdam is located on swampy zone, that

topsoil is mud-clay (2a) layer 3m depth, under is loam 2b

layer…

a.Structures of cofferdam (refer to attached drawing)

Basicly, Remove all mud-clay (2a), then fill sand and

imported soil from –3m to +3m with slope factor m=3.

Section of cofferdam is recommended as drawing showed,

with examination of Geo-slope (Seep/w vµ Slope/w)

programe to give out absorbent gradient of lower section is

0.55, slip factor is caculated by Bishop, Kminmin=1.358

The result of stress analysis & deformantion in foudation of

cofferdam has been examined by Plaxis Program and giving

out the tensile force of geotextile fabric is 113.42N/m

b. Execution method of Cua dinh cofferdam (refer to

attached drawing)

This line will have one team take responsibility to execute in

accordance with follow steps:

Using Clampshell standing on barge to dredge mud-clay 2a,

throwing into 2 sides to make 2 temporary dykes prevent

water for dry execution. at level +1.5m, the distance of 2

dykes is enough to execute cofferdam inside. with

Clampshell has a capacity 1.2m2 and Barge is 200T.

- Then keeping foudation dry, speading one Geotextile layer

with R=1.5T/m on, after that using special truck to fill sand

on from –3m to 0.0m, and From level 0.0 to +3m will be filled



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by soil with step about 30cm per one to compact reaching

engineering requirement

- Material used for filling and banking cofferdam will be taken

from specified mines and one part is from excavated soil.

- The directions of execution is showed on drawing.

II.3.Line 3: Execution method

This line is located nearly river so to execute this one, we

use dredger with Barge to carry mud, the direction is from

Dabac river to inner canal, if tidal peak we must pull Dredger

out.

II.4. Structure and execution method of intake bay.

Bach Dang river is affected by tide, current line in river is

included 2 directions, so intake bay must be perpendicular

with current line in river, basicly can be describle as follow

The trash and boom log revetment will devided into 5

opening, one is 10m width, Total length is 50m with bottom

level is –3.5m this work is located at infront of Uongbi bridge

No1 with included trast and log boom system.

to more detail of design refer attached drawings. To

execution this works Contractor will use steel pile to encircle

then pumping water out, driving concrete pile then casting

concrete revetment and other structures.

And 2 abutments will use concrete pile to execute, the

exectuion method in accordance with catalogue hereto.

To against erode of water, in line of intake bay will be also

spreaded PDTAC-M.

II.5. Structure and execution method of swing wall of

pump station.

Design: Foundation of swing wall is concrete pile M300, Wall

open directly to upstream, the level is +3m down to bottom

of canal, with thickness of wall various from 1000mm to

500mm, Refer to drawing attached.

Execution method: Contractor will use steel pile to encircle

then pumping water out, driving concrete pile then casting

concrete revetment and other structures. and it may be use

needle-filter-well t keep foundation dry.



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