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11/12/2012 JUBA, SOUTH SUDAN
How to Maintain
the Rural Road by Ourselves
Makoto KIMURA
Professor, Department of Civil and Earth Resources Engineering,
Kyoto University, JAPAN
Chairperson of Board, Community Road Empowerment (NGO)
[email protected]
How do we repair rural roads
without any machine ?
What can I do for rural people
as a geotechnical engineer.
Challenges and
Good Solutions
September, 2007
Vehicle per day < 50
Practical construction in East Uganda
May, 2008
２０１ (Times)－６０(Africa)－３６(Kenya)－１４(Expert)－６４(Countries)－0.300
Problems in rural area (Cause of the poverty)
Farm
River
Rural road
(Unpaved)
Cash Crops
Well
Main Road
(Paved)
Market
Agricultural Community
Can’t Transport
Agricultural Product
during Rainy Season
Crops are
spoiled
Can’t get
money
4
Always waiting heavy machine !!
How to empower rural
communities?
5
Which technology
can solve the problem? (Four L)
40 cm
Do-nou: GEOTEXTILE
(Japanese term of soilbag)
40 cm
Prevent floodwaters from
going over dikes
1.
2.
3.
4.
Building firm SUBBASE
Locally available material
Labour based
Low cost
Low technology
6
“MICHIBUSHIN” 55 years ago in Japan
Communities’ voice
Above those were the answers
from the group members,
“What is a road for you?”
Above those were the answers
from the group members,
“What is “Do-nou” technology
for you?”
Due to the financial deficit, roads are not maintained.
9
Japanese road condition about 50 years ago
“Do-nou” technology!!
Characteristics of “Do-nou”
40 x 40 x 10 cm, 20 kg
Material
Low cost
material
Plastic (polypropylene)
“Do-nou” bag
Bags for sugar/maize Material put inside the bag
Construction
Soil near
the site
Labor based
Simple
No curing period
Wooden mallet
Compressive
pressure
Bearing
Capacity
(250 kN)
12
How to Generate the Strength of
the ”Do-nou”?
Bag
External force
Soil
Soil is wrapped
with bag
Tensile strength
External force
applied to
“do-nou”
Tensile strength
is generated.
The soil inside
the bag is
reinforced.
Mechanism is simple.
Do-nou is the ultimate geotextile.
Careful work (compaction) is necessary.
Standard cross sections of road maintained
using “Do-nou” technology
0.8 m
The surface whose base
coarse is not reinforced settle.
0.8 m
0.2 m
Top layer
Thickness: 0.05 m
The surface whose base coarse
is reinforced with Do-nou
is firm.
14
Application of the“Do-nou”
Construction of a retaining wall with 30,000 do-nou
Application of the“Do-nou”
Do-nou
捨てコンクリト
約600
400
連結スル
連結土のう
連結土のう
連結土のう
連結土のう
縫イツケル
Tying the
openings
1600～1800
軟弱地盤
Soft
clay
N値＝１～２
N value =
1~2（単位：ｍｍ）
Unit:mm
Field construction by do-nou to reinforce soft building foundation
Mechanism where the Strength
of “Do-nou” is Generated.
σ1f
・Tension T produces an additional stress
H
Tension of bag, T
T
Soilbag
Do-nou
 01  2T B
 03  2T H
σ3f
T
・The shear destruction is done under
the stresses acting as shown in Fig.2
Tension of bag, T
B
 1 f   01  K p  3 f   03 
Fig. 1 Stresses acting on Do-nou
σ1f
Kp
: coefficient of Passive earth pressure
KP 
σ01=2T/B
H
σ3f
Soilbag
Do-nou
B
σ03=2T/H
Fig. 2 Stresses acting on particles inside Do-nou
Reference: Matsuoka, H. and Liu, S. : A New Earth Reinforcement Method using
Soilbags, London, Taylor & Francis Group, 2006．
1  sin 
 5.55
1  sin 
Internal friction angle  of
materials inside the Do-nou
1 f 
2T
2T 

 K p  3 f  
B
H

1f   3 f K p 
2T  B

 K P  1
B H

The Load F of the “Do-nou” at Failure
The load F of the Do-nou at failure
2T  B

F
 K P  1  BL 
B H

T
(1)
: Tensile Strength of Do-nou
1  sin 
KP 
 5.55
1  sin 
Internal friction angle  of
materials inside the Do-nou ＝ 44 °
B, L, H
shows the size of Do-nou
H=10
Do-nou made from polypropylene
( cm )
T = 6.0 kN/m
(1)
Reference: Matsuoka, H. and Liu, S. : A New Earth Reinforcement Method using
Soilbags, London, Taylor & Francis Group, 2006．
F  102kN(10.2tf )
Specification of Do-nou bags
Unit
Polypropylene
Woven bag
Material
Polypropylene
Size
cm
60 x 45
Weight
g /bag
42 ~ 45
Weight of 500
bags (1 roll)
Kg/500
bag
21 ~ 23
2T  B

K

1

  BL
P
B H

Number of
strings in
per inch
/inch
9-10
: Tensile Strength of Do-nou
Tensile
strength
kN/m
6.0
The load F of the Do-nou at failure
F
T
Name
KP 
1  sin 
1  sin 
B, L, H
shows the size
of Do-nou
Weight and number of strings in per inch are indicators
To see whether the bags own enough tensile strength,
which is 6.0 kN /m.
MATERIAL PUT INSIDE THE BAGS
TOP LAYER : GRAVEL
WITH OPTIMUM
MOISTURE CONTENT
INSIDE DO-NOU: IN-SITU SOIL
DIPOSAL SOIL
GRAVEL SOIL
SOIL TYPE
Single Grained
Gravel
Wide range
grained gravel
Sand
30
20
10
0
0
10
20
Strain (%)
(Settlement)
30
20
With villager at 13 countries
21
Voice of the people who experienced road
maintenance using Do-nou
• Now I am confident I can maintain the road. Initially I was
not very sure I could.
• I am very happy because the road has brought about good
positive changes to our community.
• Initially I felt it was a difficult job needing a lot of energy but
in the end I realized it was easy.
• In the beginning we did not have idea about maintaining
roads but now we have learned.
• Big improvement of the road, I got knowledge.
• I have got technology, idea and murram road. I can do it by
myself.
• I believed that the technology works on road maintenance.
22
IMPACT OF THE ROAD MAINTENANCE USING
DO-NOU TECHNOLOGY
1. The buyers come to the village
more frequently.
2. The price of the crops, vegetable
and passion fruits, have raised.
3. The income of the farmers has
increased.
4. The farmers were motivated and
expanded their farm.
5. The farmers became able to reach
the market more early in the morning, when the price was set
more highly.
6. The extension officers visit the village more frequently, then the
farmers get more skill and information of the markets from them.
7. The farmers started to new project for income generation, such
as fish pond.
23
Comparison road maintenance between
using “Do-nou” technology and
Labour based technology
Technology Motivation
Do-nou
LBT
Particiapants
Target
Main
material
Machines
1) Natural site
1) Farmers, Community
soil
Self
Unclassified
(Labour/volunteer)
1) Truck
2）Murram
development
(Spot)
3）Do-nou bags
1) Truck
1) Contractor
Labour fee
Classified
1) Murram
2) Water tank
2) Labour
3) Roller
Support , Assistance Method for LBT
Full size model driving tests
Before
After 100 times passing
Clay
500200 - 250
500 200 - 250
Gravel
800
800
50
Gravel
Clay
Cross section of Case D
Cross section of Case C
“Do-nou”
(Unit:mm)
100 times
C
D
-100
Settlement (mm)
1400
0
100
200
0
1000
2000
3000
Distance from the measuring point (mm)
Depth of rut (mm)
Material put inside Do-nou bag
0
Depth of rut：a - b
150 mm
50
Crushed stones
100
Gravel
150
200
Sand
0
50
100 150
200
The number of the passes by car
The formed rut was 150 mm deep such that it prevented the car from driving.
27
Matrix for traffic, material, maintenance and cost
Coarse material
Cost per meter (US$)
Design
Amount
of traffic
Material put in bag
Cross section
3.0
Fine materiial
Purchase material Available material
Aspahlt Crusher Murram Gravel Sand Clay
3
0
18/m3 4.4/m
Unit:m
20
8.3
5.5
4.0
4.0
4.0
Target
Do-nou, 2 layers
Do-nou, 2 layers
21.0
10.8
7.5
28.5
14.8
10.5
7.5
Do-nou, 3 layers
100
(Per day)
Asphalt t=0.05
Unit : m
Gravel t=0.15
Frequency of maintenance
51.0
Low
High
APPLICATIONS TO RURAL INFRASTRUCTURE
Retaining wall
Culvert
Log B
20 10
10 cm
: Murram
“Do-nou”
filled with
Murram
70
150
50
80
50
Log A
Dam (water harvest)
29
Technology transfer
in the world: 15 Countries, 80 km
Collaboration with
the graduate student
from Kyoto University
in Vietnam
Collaboration with
State university
in the Philippines
Projects funded by
Asian Development
Bank (ADB)
Papua New Guinea,
Timor Leste
In Ghana and Kenya, High potential of BOP business (JICA)
One of the methods for spot improvement as LBT in Tanzania
Make a good road for rural peoples!
Empower community through road maintenance
5.0 m
Do-nou
After road maintenace with do-nou,
the villagers were motivated and
did repair a bridge by themselves.
Hard cores
Murram
1.0 m
Fragments of
Broken culvert
Labor cost
3,000 US$
Material cost
2007.4
Negotiation with local government
Constructed by volunteer works
2007.8
32
Impact from Spot Improvement is
equivalent to that from Rehabilitation of hole Road?
B
7.
28 m
7.7 km
6.
28 m 5.
26 m
A
4.
26 m
1. ~ 7. : 154 m
3.
22 m
1.
2.
12 m
12 m
Spot Improvement
1. The problematic portions, which were at No.1 to No.7, were maintained.
2. In total, the portions which length was 154 m were improved using Do-nou.
3. As a result, the road from A to B, which length is 7.7 km, become passable.
4. The impact of spot improvement can be said to be equivalent to that of the
rehabilitation from A to B?
Cost of Spot improvement (154 m at No.1 to No.7, Actual): 2,920 US$
(19US$/m)
Cost of Rehabilitation from A to B (estimated ) :154,000 US$ (20US$/m: Basic rate)
Proportions of Cost of Each Work Items in
Spot Improvement using Do-nou in Tanzania
Total length : 154 m
Total cost: 2,920 US$
Total number of labour (personday): 75 (15 person x 10 days x ½
(4 hours per day))
Cost per meter (Width : 4.0 m):19 US$
Productivity per personday: 2 m
1
26
US$
%
757
26
574
20
582
20
980
34
26
1
34
20
20
2,920
100
Work rate (Break down) & Productivity of
Filling potholes and gullies using Do-nou
Work rate: 30 US$ per
Productivity:
 0.82 m3 per personday
 ( 48 Do-nou bags per personday)
m3
3
%
5
59
10
23
10
23
59
3
Filling potholes and gullies using Donou: 25.49 m3
BREAKDOWN
ITEM
QTY
UNIT
RATE(US$) TOTAL(US$)
Labour
31
personday
2.40
74
Hand rammer
30
daypcs
1.20
36
Do-nou bags
1,496
bags
0.30
449
Strings
448.8
m
0.05
21
Gravel (Stones)
25.49
m3
6.90
176
Filling potholes and gullies using Do-nou
756
5
100
%
10
5
59
3
23
100
Spot Improvement with
farmers’ initiative for self development
in Kenya
Total length : 20 m Total cost: 141 US$
Total number of labour (personday): 18 (36 person x 0.5 days)
Cost per meter (Width : 4.0 m):7.05 US$
19.0 US$ (Labour based)
Productivity per personday: 0.56 m
2.0 m (Labour based)
ITEM
7t truck
Gravel (murram)
Strings
Do-nou bags
BREAKDOWN
UNIT
RATE(US$) TOTAL(US$)
QTY
%
2
trips
32.70
65
46
14
ton
3.10
43
31
1
roll
2.18
2
2
231
day
0.13
30
21
141
100
Spot improvement using Do-nou
Make a good road for rural peoples!
Thank you for your attention!