Experiences of landslide prevention worksin Vietnam
Introduction of Landslide Disaster in Vietnam
and Application of the Japanese Technology of Landslide countermeasures

Kawasaki Geological Engineering Co., Ltd
Takami KANNO

Ph.D./PE.Jp

CONTENTS OF THE PRESENTATION
1. Introduction
ベトナムにおける防災対策の現状
2．Introduction Landslide countermeasure works in Vietnam
ベトナムで行った主な地すべり対策の紹介① Landslide control work
・Mon-Seng bridge Landslide, Lao Cai in mountainous areas
・Da Lat city Landslides ,Lam Dong occurred in urban area
② Landslide prevention work・Bai Chai Landslides ,Quan Ninh occurred along the road
3. CONCLUSION
まとめIntroduction■ In recent years, increase in various natural disasters as landslide,
due to climate changes on a global scale , becomes the serious
social problems.
近年気候変動に伴う地すべり災害多発、社会問題化■In Vietnam, the serious physical and human damages has been
occurring frequently by landslide disasters and it’s debris flowwhich caused by torrential rain.
ベトナムにおいても豪雨に伴い発生した地すべり災害によって申告な人的・物理的な被害が発生している。

Example of the slope disasters
and the countermeasuresfor landslides .

Classification of Landslides Type

Rotational landslide Translational landslideRock fallTopple

Block slide

Debris flow

Countermeasure construction of landslide
Surface Drainage
Drilling

Drainage Well
Steel Pipe Pile
ＣＶGround ＣＶAnchor

Drainage Tunnel
http://www.ktr.mlit.go.jp/river/bousai/river_bousai00000021.html

Drainage Well

Well Digging

Drainage Well↓
Drainage Drilling

Drainage Drilling
Drainage Drilling
Landslide surface

Spring water fromdrainages
http://www.maff.go.jp/tohoku/nouson/kokuei/shonai-sahi/shintyoku.html

Drainage Drilling on the groundLightweight Fill
(EPS : foamed styrol)
Embankment tothe headof landslide

GroundAnchorage

https://www.pref.nagano.lg.jp/xdoboku/chouken/jidukiyama/taisaku.html

アンカー工Comparison of disaster prevention budgets
between Lao Cai province and Shimane pref
Lao Cai province Shimane Prefecture inin Vietnam
JapanRatio

Area

6,357 km²

6,707 km²

Population

565,700

705,893

Total Budget

25.3 billion

527.7 billion

1/21

1.3 billion

39.6 billion

1/31

5.00%

7.50%

Disaster Prevention
Budget
The Ratio ofDisaster Prevention
Budget/Total Budget

The ratio of disaster prevention expenses to the total budget, which is almost the sameratio. However, the total budget in Lao Cai province is 25.3 billion yen in terms ofJapanese yen, and 527.7 billion yen in Shimane prefecture. The total budget for Lao Cai
province is only about 1/20 or less of Shimane

GDP per capita trends in Vietnam
GDP per capita has doubled in 10 years

Case Studies
Mon-Seng Bredge
Landslide
One of the most highest risk of the landslides

along the National Road Route 4

Location Map of the Survey Area

About 250km
North Westof Hanoi

Design Work of Landslide Countermeasures

Sep.2004

Jun.2012

April.2004

History of theMon-Senlandslide
JUN.２０１２

Nov.2012

Analysis of Topographic Featuresof Landslides by Terrestrial LiDAR
Ground Surface Visible!

Superposition LiDAR DEM

Topographical Map

Preliminary Results of High Density
Geophysical Exploration
Resistivity cross-section
Drilling

Drilling Servey

Design Work of Landslide Countermeasures
Drainage drilling work

LEGEND
Drainage drilling
Ground surface drainage
Scarp, Knick line

Landslide-slope surface
protection by log fence

Ground surface drainage

Design Work of landslide countermeasures
Drainage drilling work

fault gouge
gneiss or granitic
bed roksslip surface
gneiss or granitic
bed roks

Case Study
Landslides occurred at urban area
in Da Lat city ,April 2017
Location MapTOKYOLand

HANOIDA LAT
HO CHI MINH

Drainage Well Construction inVietnam
Kawasaki Geological Engineering Co.,Ltd
T.Kanno PE(Civil).JP/Ph.D

Situation near the top of the landslide
immediately after the landslidein April 2017Bên trong nhà, vết nứt chạy dọc theochân tường và trong khu vực bếpPress

Position of reference pointfor surveying
RP③
RP②
Liner PlateWell

3.5m
1m

1m

1m

RP①

PR1- 1484.789m
RP2- 1482.683m
RP3- 1486.865m

Landslide Block

Line-2

Line-180×60mLine-3

High-Density Electrical Prospecting Results
Line-1Line-2

Line-3

Landslide monitoringwith ground extensometer

Drilling survey and set-up PSG
just before the Drainage Well construction in 2020

Drilling results in 2020

Setup of water level sensor
and PSG observation device
before drilling of the Drainage Well

図８,井工現場Hình 8. Khu vực thi công giếng.

Concept of the drainage
countermeasurein the Well

Ground leveling work before excavationof Drainage Well(20 March 2021)

Before placing the concrete top plate

Placement of concrete top plate

Remove the formwork after placing
the concrete top plate14 April 2021 Sediment runoff behind the sidewall of
the drainage well by heavy rain (beginning of heaving)23 April

23 April

23 April

23 AprilAs a countermeasure against heaving, grouting wascarried out around the hollowed out Drainage Well.

Filling cavities by Grouting

Identification of the heaving area using orthoimages
and topographical contour maps createdby aerial drone photography

Aerial photography: Kawasaki Geological Co., Ltd.
Image processing: Nakanihon Air Service

Soil Improvement cross section by Grouting

Soil Improvement cross section Area by GroutingCountermeasure against heaving
Load reduction by the EPS methodEPS

A’EPS
EPSEPSEPSEPS

A

A’EPS

A

Displacement prediction of drainage well after installationof bottom concrete
Inclination of the top plateof the catchment wellPSG

Displacement stop after installationof bottom concrete

2021.9.27 Drainage Drilling

Case Studies
Bai Chai district ,Quan Ninh
Landslides occurred along the road［MAY 2015］
Before countermeasure work

［AUG 2019］
AAfter countermeasure work

On-Site Disaster SituationConclusion■Suggest the importance of disaster prevention and mitigation, that should take somemeasures before the serious damages will occur (ex:hazard map).
防災・減災に重要なのは、被害を受ける前に事前に手を打っておくこと(ハザードマップ)■An important point for Japanese companies doing business in Vietnam is to be able todeploy as many solutions as possible.
日本の会社がベトナムで業務を行うためには、できるだけ多くのソリューションを有していること。
■It is also important to provide technical solutions that allow us to obtain a large
amount of geological information that will serve as the basis for construction before
construction.
そして、施工前に施工に必要な多くの地質情報を得るための技術ソリューションを提供できること。
■And last , it is important have enthusiasm and the ability to complete the project.
最後に重要なのは熱意とプロジェクトをやりとげる実行力です。

Thank you for listening !