Application of Integrated Geophysical Exploration & Dyke Database for Dyke Inspection T. KOIKE Project for Building Disaster Resilient Society in Vietnam Phase-2
Application of
Integrated Geophysical Exploration
& Dyke Database for Dyke Inspection
T. KOIKE
Project for Building Disaster Resilient Society
in Vietnam Phase-2
Dyke is composed of heterogeneous materials due to the long history of
construction. The deference of materials may become weakness of the
dyke body.
Ant nest and/or the other animal nests also cause weakening.
In view of long life of the dyke, geophysical exploration and compiling
dyke database are necessary.
Ant Nest in the Dyke Damage History of the Dyke, Ca River
INTRODUCTON
材質の密実度の指標となる表面波探査と、透水性の指標とな
なる比抵抗電気探査を組み合わせた評価手法。
下記クロスプロットの左上(低表面波速度、高比抵抗値)は、緩みが生じ透水性が高まっており、浸透崩壊の危険性が高い箇所といえる。
堤防材質データの入手が困難なベトナム国のダム堤体評価(1次スクリーニング等)に適している。
Deference before and after the
earthquake in 2011 (MLIT)
High Risk
Integrated Geophysical Exploration
Integrated Geophysical Exploration is
an assessment technology by
combination of
Surface-Wave Exploration to measure
the compaction degree and
Resistivity Exploration to measure the
permeability of the materials.
The left-upper area of
LOW surface wave velocity and HIGH
resistivity in the bellow cross-plot may
shows loose / permeable degraded
material, where the slope failure risk is
relatively high.
Application into Integrated Geophysical Exploration
The Integrated Geophysical Exploration
method was implemented for safety
assessment of river dykes in JICA TCP
in Bangladesh.
The high risk zone in the each pilot
project site was clearly extracted by this
method.
The result will be utilized for basic
planning of countermeasures such as
waterproof wall.
Out of Dyke
Inside of Dyke
Roof Tier
Foot
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Distance(m)
-14
-12
-10
-8
-6
-4
-2
0
Dept
h(m
)
-14
-12
-10
-8
-6
-4
-2
0
dept
h(m
)
0
20
40
60
80
100
200
300
400
500
Resistivity(ohm-m)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Distance(m)
-14
-12
-10
-8
-6
-4
-2
0
dept
h(m
)
-14
-12
-10
-8
-6
-4
-2
0
Dep
th(m
)
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0.24
0.28
S-Wave Velocity(km/s)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100-14
-12
-10
-8
-6
-4
-2
0
-14
-12
-10
-8
-6
-4
-2
0
Distance(m)
Depth(m
)
Depth(m
)
0
100
200
300
400
0 0.05 0.1 0.15 0.2 0.25 0.3
1
2
3
4
+
2D Resistivity Exploration
Surface Wave Exploration
Result Example of IGE in Bangladesh
Application into Integrated Geophysical Exploration
Inspection Planning for Integrated Geophysical Exploration in Kasumigaura Lagoon (MLIT)
In river management, river bathymetric survey
is also important as well as inspection of river
structure.
The project supported bathymetry survey using
acoustic sounder in the Ca river.
The obtained bathymetry data was combined
with high-resolution Digital Elevation Model
(DEM) as River Geographical Database.
User can extract any cross-sections from the
database.
Bathymetry Survey for Dyke Database
Bathymetry with DEM in Ca river
Dyke Database prepared by UAV
UAV (unmanned aerial vehicle) is also applicable
for Dyke Database in order to obtain wider and
detailed aerial photograph and surface elevation
data set.
The resolution = 2-10 cm, the accuracy < 10 cm.
CIM : Construction Information Model (MLIT)River Photograph
C/P Training in Japan
Application for Dam Safety Management
River Dyke and Earth Dam are basically same structure.
Integrated Geographical Exploration method, and Dyke Database can
be applied for Dam Safety Management in future.