Dissertation summary: Research on characteristics of Quaternary sediments and the relations to land subsidence in the West area of Hanoi

MINISTRY OF EDUCATION
AND TRAINING

VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY OF SCIENCE AND
TECHNOLOGY

NGUYEN VAN BINH

RESEARCH ON CHARACTERISTICS OF QUATERNARY
SEDIMENTS AND THE RELATIONS TO LAND SUBSIDENCE
IN THE WEST AREA OF HANOI
Speciality: Geology
Code: 62 44 02 01

SUMMARY OF GEOLOGY DOCTORAL THESIS

HA NOI, 2015


The thesis was completed at: Graduate University of Science
and Technology, Vietnam Academy of Science And Technology

Scientific Supervisors:
1. Assoc. Prof. Dr. Do Minh Duc
2. Assoc. Prof. Dr. Doan Dinh Lam

Reviewer 1: Dr. Do Van Nhuan
Reviewer 2: Assoc. Prof. Dr. Nguyen Huy Phuong

Reviewer 3: Assoc. Prof. Dr. Pham Quy Nhan

This thesis is going to be defended at the council of doctorate thesis
examiners of Graduate University at:....................................................
............hour, day

......., month

...year 2015.

Thesis can be found at:
- National Library, Hanoi
- Library of Vietnam Academy of Science and Technology
- Library of Graduate University of Science and Technology


1
PREFACE

The West Hanoi (formerly Hatay province) was merged into Hanoi
since 2008, this area in the process of urbanization at high speed.
Geological characteristics in this area considered complex, the limestone
layer widely distributed, high fractured and somewhere has underground
karst. The Quaternary sediments include many kind and difference in ages,
origin, composition, physical - mechanical properties. Especially, existence
of the soft soil layer has thickness and distribution irregular.
From 2007 to present, in some places as Ngoc My, Thach Than communes
(Quoc Oai district) appeared many cracks on the walls of old constructions
with low loading capacity and these cracks are expanding. Research results
identified that the surface in this area being subsidence, expressions of land

subsidence complex and unpredictable. In additions, some geological
hazards have been occurred with damages and destroy constructions. Land
subsidence and ground collapse occurred for many reasons and related to
Quaternary sediment (lithological composition, physical - mechanical
properties, distribution) and groundwater. However, the detail researches of
them in the West area of Hanoi not very much. Therefore, PhD student has
chosen the topic: “Research on characteristics of Quaternary sediments
and the relations to land subsidence in the West area of Hanoi”.
1. The objective of the thesis
To elucidate of characteristics of lithological composition, physicalmechanical properties and distribution of Quaternary sediments, the
relationships between sediment characteristics, especially, the soft soil
layers in the West Hanoi to land subsidence and ground collapse; then to
propose prevention measures for sustainable development of infrastructure.


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2. Object and scope of the study : The Quaternary sediments in the West
area of Hanoi and its relation with land subsidence. In the thesis, land
subsidence is considered the deformation of the surface by two forms:
First: ground subsidence is the deformation of soil foundation due to the
change effective stress leads to compaction of the soil when the water table
lowered. Thesis research on a large scale ground subsidence (regional), not
analysis in a specific location of construction.
Second: ground collapse due to human activities creates voids in the soil
(the exploitation of underground water) and natural voids relatively close to
the surface (karst) leads to the collapse of soil and forming sinkholes.
The study scope includes Quoc Oai, Chuong My and My Duc districts,
3. Research contents
- Characteristics on lithological, physical - mechanical properties and
the distribution of Quaternary sediments in the West area of Hanoi.

- The relationship between Quaternary sediment to land subsidence
hazards in the West area of Hanoi.
- Proposed solutions to preventing land subsidence and ground collapse,
serve for development of infrastructure sustainable.
4. Database of the thesis
+ The reports geotechnical investigation in the study area including 431
boreholes, depth from 7-50 meter; 1272 samples, 1778 of standard
penetration test (SPT) and 47 of vane test.
+ The theme "Research the potential geological hazards related to the
process of urbanization in the West area of Hanoi" in Hanoi University of
Natural Resources and Environment. PhD student as main responsible
person, acceptances 2013.
+ Topic "Research geohazards ground subsidence and propose solutions to
handle at Km16, provincial road 419 of Quoc Oai town, Hanoi" by the
Vietnam Institute of Geosciences and Mineral Resources (2009).


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+ Project "Mitigation of Geohazards in Vietnam" by Vietnam National
University (VNU) and the Norwegian Geotechnical Institute (NGI).
+ The reports on the survey results and determined the cause of ground
collapse and execute fillings material for sinkholes in Hamlet 16, village
Ang Ha, Le Thanh commune and Team6, Thuong village, Xuy Xa
commune, My Duc district.
5. Defending issues
Issue 1: Quaternary sediments in the West area of Hanoi is divided into
four profile types with 18 sub-profile types based on sediment
characteristics, age, origin and distribution.
Issue 2: Land subsidence and ground collapse in the West area of Hanoi
took place with local nature. Land subsidence occurred in areas distribution

of sediment in profile type 1 (sub-profile types 1.2, 1.3 and 1.4) and profile
type 3 by the water table was lowered. Ground collapse occurred in areas
distribution in profile types 1 and 3 by extraction underground water
unreasonable and combination with the fractured limestone layer,
underground karts.
6. The new scientific finding of the thesis
- Base on association of sediment characteristics and physical-mechanical
properties of soils; determine the scope and depth distribution of
Quaternary sediments in the West area of Hanoi.
- Determination of profile types and sub-profile types of Quaternary
sediments and their spatial distribution in the West area of Hanoi.
- Clarification of causes on local land subsidence and surface ground
collapse in the relations to Quaternary sediments, especially the soft soil
layers in the West area of Hanoi.
- Zonation of the areas with potential risk of land subsidence hazard in
relations to the Quaternary sediment profiles, karstic distribution in the
West area of Hanoi.


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7. The scientific significance and practice of thesis
Scientific significance: characteristics and the distribution of Quaternary
sediments in the West area of Hanoi and its relations to the land
subsidence, ground collapse in this area are clarified. Determining the
cause of land subsidence and ground collapse.
Practice significance: results of research to explain the causes,
mechanisms of formation and development of land subsidence, define the
areas with a high risk of land subsidence, raising warnings on human
activities inducing the occurrence of land subsidence, which helps to
outline rational land use and sustainable development of infrastructure

8. The layout of the thesis
Preface
- Chapter 1. Overview of research and natural conditions, economic and
social in the West area of Hanoi
- Chapter 2. Methodology and Research Methods
- Chapter 3. Characteristics of Quaternary sediments in the West area of
Hanoi.
-Chapter 4. The relationship between Quaternary sediment and land
subsidence, ground collapse
Conclusions and Recommendations
CHAPTER 1
OVERVIEW OF THE RESEARCH AND CONDITIONS OF NATURAL,
ECONOMIC AND SOCIAL IN THE WEST AREA OF HANOI
1.1. Historical of geological research
1.1.1. Period before 1975
The geological study primarily serves for exploration and mining. Studies
of sediment little attention. After 1965, there is some research is published.
1.1.2. Period after 1975 so far
After 1975, there are many researches of Quaternary sediments
comprehensively published. The North Vietnam Geological Mapping


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Division finished geological mapping group Ha Dong-Hoa Binh(1988) and
Hanoi map group (1994), scale 1:50 000. Quaternary sediments in the West
area of Hanoi divided into four formations: Hanoi, Vinh Phuc, Hai Hung
and Thai Binh. Also, the Geology Division, Geological Corps number 6,
29, 79, 51, 54 and 64 have made mining exploration, mineral occurrences,
exploration, observation and exploitation underground water.
1.2. Overview of researches on land subsidence and its relation with

Quaternary sediments
1.2.1. The researches around the world
According to Winslow and Wood, for the fine-grained material
saturated with water, the amount of subsidence is equivalent to the amount
of losing pore space by compaction. Poland and Davis determined the
cause of land subsidence included: 1)loadings at the land surface;
2)vibratory near the land surface; 3)the compaction by irrigation and
agricultural production; 4) the dehydration and shrinkage of sediment;
5)oxidation of organic materials; 6) lowering of the groundwater level; 7)
pressure drop.
According to Leake S. A, in case the aquifer sandwiched the layers (or
clay- silty clay lenses), when the pressure in the aquifer was lowered lead
to increased of strain compression for the aquitard and making them
compact (thinner) and is regarded as the subsidence of the land surface, the
process of settlement is irreversible.
Amin. A and Bankher. K gave different reasons cause ground
subsidence in Saudi Arabia. In addition to natural causes, the authors
suggest that cause land subsidence occurs due to excessive exploitation of
ground water from deep aquifers.
In Shanghai city (China), the Quaternary sediments thickness of 300m.
Land subsidence in Shanghai was first reported in 1921 with the average
rate about 21cm/year. In 1965, the total settlement in Shanghai about


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2,63m. Chai JC et al, Xiao-Qing Shi concluded: the consolidation of the
clay layer, clay mud contributes approximately 80% of total subsidence.
Bangkok capital of Thailand in Chao Phraya delta. Geological section
in here includes 8 aquifer composed of sand with gravel sandwiched with
clay, soft soils located near the land surface with an average of 14m

thickness. Since 1969, the phenomenon of land subsidence more attention
when there are many indicators to be monitored in Bangkok and get the
attention of many scientists. According to Nutalaya (1989), the most
powerful of land subsidence in Bangkok over the period 1933-1987
approximately 1,60m and by 2002 the settlement was 2,05m
In India, Sahu and Sikdar studied the geological features in the Kolkata
city and swamps area in Eastern Kolkata, West Bengal. Quaternary
sediment in this area included clay, mud and sand layers. Calculation
results show that amount of land subsidence varying from 1,12mm to
43,8mm/year, average of 13,53mm/year. Estimates, amount of land
subsidence corresponding with 1m lowered hydraulic pressure about 1,79
cm to 10 cm, average of 3,28 cm.
1.2.2. The researches in Vietnam
In Vietnam, land subsidence phenomenon happens quite universal in
Hanoi, Ho Chi Minh city, Hai Phong, Can Tho, Ca Mau and some
provinces, cities in Mekong river delta
1.2.2.1. In Hanoi and Ho Chi Minh city
In Hanoi, land subsidence has been warning by scientists from the 80s
of 20 century. Many authors have published results of researches on land
subsidence in Hanoi (old) such as Nguyen Kim Cuong (1995);Tran Trong
Hue et al (1995, 1996); Doan The Tuong (1999); Tran Van Hoang and Bui
T. Bao Anh (2000); Pham Quy Nhan (2004); Tran Manh Lieu (2005); Tran
Manh Lieu and Doan The Tuong (2006); Tran Van Tu; Dang.V Khac...etc.


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In Ho Chi Minh city, since 1992 (the first year of land subsidence
monitoring through satellite images) to 2011, has recorded 17/24 districts
was sinking from 20 cm to 50cm. Subsidence increasing and proportional
to speed of urbanization

1.2.3. The researches in the West area of Hanoi
1.2.3.1. Research overview
Vietnam National University (VNU) and Norwegian Geotechnical
Institute (NGI) carried out the project "Mitigation of GeoHazards in
Vietnam". One of the tasks of the project is research the phenomenon of
land subsidence in Hanoi.
The Geophysics Technology JSC; Vietnam Institute of Geosciences and
Mineral Resources; Divison of Water Resources Planing and Investigation
for the North of Vietnam researches some topics about land subsidence,
ground collapse in My Ducm, Quoc Oai district. The positions was collapse
has fine sand and soft soil layers (bmQ21-2hh) with considerable thickness.
Nguyen Van Binh et al researched engineering-geological and
geohazard related potential the process of urbanization in the West area of
Hanoi (Quoc Oai and vicinity areas), analyze the effective of soft soil
layers, groundwater exploitation and relationship with land subsidence.
Most of researches show that the risk of land subsidence occurred in
areas distribution of soft soil layer, especially when they are distributed
above aquifers and within the influence of the water table was lowered.
1.2.3.2. General comment
a, About the research issue on Quaternary sediment:
- The depth studied of sediment within 20m depth
- The detail division on the scope and depth distribution of sediments with
different composition of the lithological is limited.
- Relationship of Quaternary sedimentary with bedrock, especially with to
fractured limestone and underground karts have not been clarified.


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b. About the studies of geological hazards related to Quaternary sediments
in the process of urbanization

Most of theme, research projects primarily focus on geohazards
assessment of status events such as landslides, river erosion. The researches
on land subsidence occurred in Quoc Oai and My Duc district mainly to
assess the status and treatment of complications, the causes of geohazards
have not yet been elucidated.
1.3. Natural conditions and socioeconomic in the West area of Hanoi
1.3.1. Topography - Geomorphology feature:
1.3.1.1. Topography feature: includes lower mountain, hill and plain
1.3.1.2. Geomorphology feature: includes erode and accumulation terrains.
1.3.2. Geological and structural feature
1.3.2.1. The geological formations before Quaternary.
The geological formations before Quaternary from Paleozoic to
Mezozoi include geological formations in order from old to recent as
follows: Na Vang (P2 nv); Yen Duyet (P2 yd); Vien Nam; Tan Lac (T1o tl);
Đong Giao (T2 dg); Nam Tham (T2 nt) and Song Boi (T23sb)
1.3.2.2. The Quaternary: Quaternary sediments in the West area of Hanoi
including four formations: Hanoi, Vinh Phuc, Hai Hung and Thai Binh.
1.3.3. Hydro-geological feature in the West area of Hanoi.
Ground water in the West area of Hanoi exist two kind include: water in
the pore of the unconsolidated Quaternary sediments and water in fissures,
karst in limestone of Dong Giao and NaVang formations.
CHAPTER 2. BASIC OF THEORETICS AND RESEARCH
METHODOLOGY
2.1. Basic theoretics
Oscillation of sea level to the formation and distribution of sediments:
The correlation between speed of sediment deposit, tectonics and sea
level fluctuation plays a key role during the formation and development of
deltaic.

9
D e lu v i

w e a th e ri n g
c ru st

A lu v i

P ro l u v i
M o u n ta i n o u s
riv e r

D e l ta

M id lan d
riv e r

D e l ta
p lain

R iv e r p l a i n

D e l ta f ro n t

P ro d e l ta

S e a l e v e l a t h i g h ti d e
S e a l e v e l a t l o w tid e

B e d ro c k

C h a n e l lag

I n te r ti d a l a r e a
S a n d ri d g e
e s tu a ry

Figure 2.2. Facies transition diagram from the mountains to the delta [22]

Transfer of facies in the West area of Hanoi are outlined in the diagram:
proluvi→ mountainous and highland river → plain river → plain delta
+

+
+ ++ +

+
+
+

+
+

Lu tích
(Proluvi) (P)

S«ng miÒn
nói
S«ng miÒn
Trung du
A

g)
g s« n
ac (lßn
båi)
i
·
Àaf (b

§ång b»ng

al (hå mãng ngùa)
ac

(a3)

af

af
ac

am1

am2

+

am2

am1

am2

am3
am3

ĐBCT
(delta plain)

TiÒn ch©u thæ
(delta front)

(Prodelta)

Figure 2.3. The distribution of depositional environments in spatial [22]

Quaternary sediments in the West area of Hanoi formed in the context
of closely related with the oscillations of the sea level, river activities and
interaction between river and the sea. Research the features of Quaternary
sediments and relationship with land subsidence needed have to integrate
the features of sediment and the physical-mechanical properties of soil and
Assessment of the status of human activities to natural conditions, and
needs a suitable method comprises: the methodological to research on


10
characteristics

of

Quaternary

sediments

(lithological

composition,

distribution and relationships in spatial), Experimental methods of physical
and mechanical properties of the sediments and the methods of calculation
and forecasting.
2.2. The research methodology
Systems of research methods used include: field survey method;
Geophysical methods; Drilling and sampling methods; Grain size analysis
methods; Analysis of mineral composition; Experimental methods of
physical and mechanical properties; Analysis on indicators of
environmental method; Interferometry technology InSAR method; Data
processing method; Kriging interpolation method; Forecasting land
subsidence method.
CHAPTER 3. FEATURES OF QUATERNARY SEDIMENT
IN THE WEST AREA OF HANOI
Quaternary sediments in the Western area of Hanoi includes four
formations: Hanoi, Vinh Phuc, Hai Hung and Thai Binh.
3.1. Hanoi formation (Q12-3 hn)
3.1.1. Alluvial- proluvi deposit (apQ12-3 hn)
Aluvi-proluvi deposit of Hanoi Formation consists of 3 parts:
- Part 1. Cobbles, pebbles, polymictic minerals, multi colors mixed with
gravel, sand and silt, lightning yellow, yellow-brown. Composition of
mainly quartz pebbles (50%), mafic volcanic rocks (30%). In addition,
composition of sediment contained sandy-siltstone, tuffaceous, size from 5

-15cm. Composition of pebbles and gravel in some places up to 70%; sand
20-25%, clay, silty 5-10%.
- Part 2. Sand and silty, lightning yellow, russet contain quartz grit.
Composition mainly of quartz sand, silica, sharp, irregular, contain small
grit. The thickness of sediment from 7.5m to> 20m. Composition of
particles size: sand 50-75%; gravel 5-20%; clay, silt 5-10%. Parameter of
grain size: Md=0,33-0,4mm; Ro= 0,12-0,2; So= 3,3-4,5. SPT test: N=2025.


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- Part 3. Clay, silty yellowish brown, brownish red, contained many laterite
grit on surface layer. Composition of particles size: clay 45-53,4%, silty
19%-22,8%, sand: 15%-21% and gravel from 3,1% to 5,5%. The
parameters of grain size: Md = 0,0055mm; Sk=0,21-0,3; S0=3,02 – 4,15.
Environmental indicators: pH=6,6, Kt=0,24. SPT test: N30=17- 42, in near
surface bedrock N30=30-50 to N30 = 60-70.
3.1.2. River chanel deposit (aQ12-3 hn)
Pebbles, gravel, sand grey-yellow, light grey, multi mineral, gray,
cobbles size from 2cm to 10cm. Composition of sediment include: cobbles
51,4%-60%, gravel 15,5% - 20,4%, sand 18-27%. SPT test: N30=50/7cm.
3.2. Vinh Phuc formation (Q13 vp).
3.2.1. River chanel deposit
Sand, sand with silt, gray yellow, gray blue, light gray, somewhere
sandwiched lens of small grit. The mineral of sand is quartz 70-80%, pieces
of grit, less mica. Composition of particles size: sand 65.9%-71,7%, silty
25,1%-27,1% gravel 1,3-7,5%. Parameter of grain size: Md= 0,28 0,42mm; So=2,5-3,2; Sk = 1.2-1,45, medium selectivity. SPT test: N30=1634, the density of sand γs=2,66g/cm3;
3.2.2. Flat plain deposit
Clay, silty clay with patchy color. The mineral composition of clay is
kaolinite and hydromica, composition chemical include SiO2 (50-70%), Al2O3
(15-23%), Fe2O3 (2-5%), TiO2 (0.5-1.8%). Environmental Indicators: pH =7; Kt =

0,28. In Quoc Oai district, composition of particles size: clay from 30% to
75%; silt from 11% to 34% and sand from 7% to 20%. Parameter of grain
size: Md=0,015-0,005mm; Sk=0,5-0.7; S0 = 3,1-5,5. In Chuong My district:
composition size: clay 39% - 51%; silt: 35%-43% and sand: 27,4-31,7%.
Parameter of grain size: Md=0,007-0,020mm; So=3,29-4,43; Sk = 0,670,86. In My Duc district: composition of particles size of clay 39,5% -


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57,5%; silt: 38,5%-45,8% and sand: 8%-14,7%. Parameter of grain size:
Md=0,007-0,014mm; So=3,46-4,21; Sk = 0,55-0,75.
3.3. Hai Hung formation.
3.3.1. Alluvial - marine deposit (amQ2 1 hh)(?)
Fine sand, gray-brown, gray, narrow distribution in Can Huu, Ngoc My
communes; Quoc Oai town (Quoc Oai district) and Bot Xuyen, Hop Tien
communes (My Duc district). Composition of particles size: sand 94-99%,
the rest are small grit. Parameter of grain size: Md=0,358-0,372mm;
Sk=1.1-1.12; So=1.27-1.45. SPT test: N30=12-23; density of sand: γs=2.652.67g/cm3; friction angle: αwet=280-300;

αdry=330-34030’; void ratio:

emin=0.702-0.735; emax= 1.023-1.085.
3.3.2. Bog - marine deposit (bmQ21-2 hh)
Clay-silty, clay-sand contained organic dark gray. Composition of
particles size: sand 19%-43.5%; silt 18%-34%; clay 34.5%-61.5%.
Parameter of grain size: Md=0,01-0,070mm; So=3,2-3,6; Sk=0.8-1.1.
Sediments distributed in center of Quoc Oai and neighboring areas as Dong
Quang, Thach Than, Ngoc My, Tan Phu communes, in Dong Son, Thuong
Vuc, Dong Phu communes (Chuong My) and widely in My Duc district.
3.3.3. Marine deposit (mQ21-2 hh)
Green-gray clay, gray-yellow. The mineral composition of clay is

kaolinite hydromica-monmoriolit or hydromica-kaolinite-chlorite. Parameter
of grain size: Md = 0,005-0,01mm; So=2,3-2,5. Environmental indicators:
pH=7-8, Kt=1,03-1,06, Fe+2S/Corg=0,25-0,5. The chemical composition:
SiO2:54,9%; Al203:18%; Fe203:5,27%; Ti02:0,78% and others 10,12%. The
composition of particles: sand 20-29,5%; silt 21-28.5% and clay 4258.5%[33]. SPT test: N30 = 6-12, stiff clay.
3.3.4. Alluvial - bog deposit
Narrow distribution, dispersed in coastal areas of the delta, small
thickness. The composition: silt-clay, clay, silt, sand-clay with organics.


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3.4. Thai Binh formation (aQ23 tb)
3.4.1. River chanel deposit
Fine sand grained, brown-yellow, gray yellow. In My Duc district, the
composition of particles: sand 82,2-94,3% silt 4%-12,8%; clay 2%-5%,
parameters grain size: Md=0,128-0,224mm; So=1,8- 2,53; Sk=1,15-1,35. In
Quoc Oai district, the composition of particles: sand 71.6-90.73%; silt
6,3%-21,8%; clay 3%-7%; grain size parameters: Md=1,4 -0,231mm; So =
1,65-1,85; Sk=0,97-1,15. Composition of mainly quartz sand (80%-85%),
small grit and mica, medium selectivity.
3.4.2. Flat plain deposit
Clay, silty clay and sand brown, yellow-brown, yellow-gray, browngray. The mineral composition include kaolinite clay, hydromica,chlorite.
In Quoc Oai district, components grai size: clay 31,5%-72,5%; silt 32%-55%;
sand 0,6%-7,4% and the parameters of grain size: Md =0,005-0,013mm;
So=2,6-3,8; Sk =0,73-0.92. In My Duc district, components grain size: clay
30%-45%; silt 39,5%-59,7%, sand 2,4%-10% and parameters of grain size:
Md=0,0045-0,015mm; So=3,0-3,75; Sk =0,87-0,95.
3.5. The profile types of Quaternary sediments in West area of Hanoi
3.5.1. Purpose and principle to division of profile types of Quaternary
sediment

Principle to division:
The profile types are division based on the stratigraphy of Quaternary
sediments formation in research area. The sub-profile types sections are
division based on the features of the sediments.
3.5.2. The profile types of sedimentary and distribution in spatial.
3.5.2.1. Profile type 1
- Sub-profile type 1.1:distribution in Can Huu, Liep Tuyet (Quoc Oai).
- Sub-profile type 1.2: distribution in SongDay bridge and some places
along the Thang Long avenue.
- Sub-profile type 1.3: distribution in East of Chuc Son town.
- Sub-profile type 1.4: distribution in An Thuong commune, Hoai Duc


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Mặt cắt điển hình
kiểu 1
a(f) Q 2³ tb

Phụ kiểu 1.1

Phụ kiểu 1.2

Phụ kiểu 1.3

Phụ kiểu 1.4

a(c)Q 2³ tb
aQ 2³ tb

bmQ2 ¹-² hh

amQ 2¹-² hh
a(f)Q 1 ³ vp

a(f) Q 2³ tb
amQ 2¹-² hh

a(f) Q 2 ³ tb

a(f) Q 2³ tb

bmQ 2¹-² hh

bmQ 2¹-² hh

amQ 2¹-² hh

a(c)Q 1³ vp

a(f)Q 1³ vp

ap,a(f) Q 1 ²-³hn

apQ 1 ²-³hn

apQ 1 ²-³hn

aQ 1 ²-³hn

aQ 1 ²-³hn

P2 nv

P 2 nv

P 2 nv

P2 nv

P2 nv

bmQ 2¹-² hh

a(f)Q 1 ³ vp

a(c)Q 1³ vp

Figure 3.26. Profile type 1 and sub-types of sedimentary

3.5.2.2. Profile type 2
Mặt cắt điển hình
kiểu 2

Phụ kiểu 2.1

Phụ kiểu 2.2

Phụ kiểu 2.3

Phụ kiểu 2.4

a(f)Q 1³ vp
a(c)Q 1 ³ vp

a(f)Q 1³ vp

a(f)Q 1 ³ vp

apQ 1 ²-³hn

apQ 1 ²-³hn

apQ 1 ²-³hn

a(c)Q 1³ vp

T2a dg

P2 nv/ T 2a dg

T 2a dg

P2 nv

a(f)Q 1³ vp
T2a dg

Figure 3.27. Profile type 2 and sub-types of sedimentary

- Sub-profile type 2.1: distribution in junction area from hilly, mountainous
to the plains in western Quoc Oai district, Mieu Mon.

- Sub-profile type 2.2: distribution discontinuous in Hoang Van Thu, Thong
Nhat, Dai Yen communes and a part of Phu Nghia commune (Chuong My).
- Sub-profile type 2.3: distribution with narrow, discontinuous in Dinh To
village, Ngoc Liep commune (Quoc Oai district) and a part of Phu Nghia
commune (Chuong My district).
- Sub-profile type 2.4: distribution of a strip stretching from Quoc Oai town
to Dai Dong commune, Chuong My district.
3.5.2.3. Profile type 3
- Sub-profile type 3.1: distribution in Yen Noi village, Dong Quang
commune, Quoc Oai district.


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- Sub-profile type 3.2: distribution of Quoc Oai town and neighboring area
as Dong Quang, Thach Than communes, Western Quoc Oai urban area
(Quoc Oai district) and My Thanh, An My, An Tien, Bot Xuyen, Phu Lien,
Phu Luu Te, Xuy Xa communes (My Duc district)
- Sub-profile type 3.3: distribution in Le Thanh, Xuy Xa communes, My
Duc district Phu Chinh village - Hoa Chinh commune, Chuong My district
and Giang Soi village, Dong Tien commune, Ung Hoa district
Mặt cắt điển hình
kiểu 3
a(f)Q 2³ tb

Phụ kiểu 3.1

Phụ kiểu3.2

Phụ kiểu 3.3

a(f)Q 2³ tb

a(f)Q 2 ³ tb

Phụ kiểu 3.4

Phụ kiểu 3.5

a(c)Q 2 ³ tb
mQ 2 ¹-² hh
bmQ 2¹-² hh
amQ 2¹-² hh

a(c)Q 2³ tb

a(f)Q 1³ vp

bmQ 2¹-² hh

bmQ 2¹-² hh

bmQ 2¹-² hh

aQ 2³ tb

bmQ 2¹-² hh

a(c)Q 1³ vp

a(c)Q 1 ³ vp

a(f)Q 1 ³ vp

a(f)Q 1³ vp

bmQ2 ¹-² hh

a(f)Q 1 ³ vp

T 2a dg

T2a dg

T2a dg

T2a dg

mQ 2 ¹-² hh

a(c)Q 2³ tb

mQ 2 ¹-² hh

T2a dg

T2a dg

Figure 3.28. Profile type 3 and sub-types of sedimentary

- Sub-profile type 3.4: distribution in SongDay bridge area (route Do Xa –

Quan Son) and some parts of the Xuy Xa, Le Thanh communes (My Duc
district), Western Quoc Oai urban area (Quoc Oai district ).
- Sub-profile type 3.5: distribution in South of Dai Nghia town and
neighboring areas (Ung Hoa district )
3.5.2.4. Profile type 4
- Sub-profile type 4.1: widely distribution in delta fringe of West Quoc Oai,
Chuong My districts and partly in Dong Tam commune, My Duc district.
- Sub-profile type 4.2: widely distributed in Quoc Oai, Chuong My
districts.
- Sub-profile type 4.3: distributed in Van Con commune of Hoai Duc
district, in East-Northeast of Quoc Oai district.


16
- Sub-profile type 4.4: distributed in an Phu commune (Quoc Oai district),
Van Con, An Thuong communes (Hoai Duc district).
- Sub-profile type 4.5: distribution in Tan Phu and Dai Thanh communes
(Quoc Oai district).
Mặt cắt điển hình
kiểu 4

Phụ kiểu 4.1

Phụ kiểu 4.2

Phụ kiểu 4.3

Phụ kiểu 4.4

Phụ kiểu 4.5

a(f)Q2 ³ tb
a(c)Q 2³ tb

aQ 2³ tb

a(f)Q1 ³ vp

a(f)Q 2³ tb

a(f)Q 1³ vp

a(f)Q 2³ tb

a(f)Q 2³ tb

a(f)Q 2 ³ tb

a(c)Q 1³ vp

a(c)Q 1³ vp

ap, a(f)Q 1 ²-³hn

apQ 1 ²-³hn

aQ1³ vp

aQ 1³ vp

aQ 1 ²-³hn

aQ 1 ²-³hn

T2 a dg

T 2a dg

P 2 nv

P2 nv

P2 nv

P 2 nv

a(c)Q 1³ vp

Figure 3.29. Profile type 4 and sub-types of sedimentary

CHAPTER 4. RELATIONSHIP BETWEEN QUATERNARY SEDIMENT
WITH LAND SUBSIDENCE, GROUND COLLAPSE
4.1. Features of land subsidence in the West area of Hanoi
4.1.1. Current situation

Estimated of land subsidence in Hanoi by interferometry technology
from february 2007 to June 2008 shows that some regions of the Hanoi,
including some place in Western areas being subsidence from 3cm to 9cm.

Figure 4.2a. Cracks extending on old

walls and concrete roads in East hamlet,
Phu My village, Ngoc My commune,
Quoc Oai district

Figure 4.2b. Cracks expanding on old
walls in the Xuan Coc hamlet, Phu
My village, Ngoc My commune, Quoc
Oai district

Results survey on status of old house with low loading, brick foundation
in Ngoc My, Thach Than communes (Quoc Oai district) shows that most of


17
these houses have been cracked. Cracks appeared around from 2008 to the
present.
Calculation of settlement results
Độ lún do hạ thấp mực nước ngầm tại thời điểm năm 2008
S
(cm)

10.3

5

12

11

9.6

7

10 8.8

CHÚ GIẢI
aQ 2 ³ tb Sét màu xám nâu,
vàng nhạt, dẻo mềm
Cát hạt nhỏ mịn màu
aQ 2 ³ tb
xám nâu, xám vàng
21.5
Sét, màu xám xanh, xám
mQ 2 ¹-²hh
vàng, dẻo cứng
Sét, bột lẫn hữu cơ màu
bmQ ¹- ²hh
xám, xám đen, dẻo chảy
2

aQ 1³ vp

Sét loang lổ bị laterit
hóa, dẻo cứng

Cát hạt thô vừa màu
xám vàng, chặt vừa
MNN năm 2000=2.5-3m

Cao độ (m)

aQ 1³ vp

10
0

4.2

7.6
8.5

4.7
6.3

11.8

22m
20

-20

aQ 2³tb

2.1

28.3
34.7

1.2
7.6

6.2

11.7

bmQ 2¹ -²hh

5.2
8.2
11.7

6.0

20

36m

39.3

P2 nv

45.8

HKBT-CS 47
HKBT-CS46 HKBT-CS 50

8.61

5.96

6.18 6.2

bmQ 2¹- ²hh

18.3
19.5
20.5 21.2

aQ1³ vp

-40
HKC-CS04

2.5
11.2

12.0

15
20

3.0

42.3

43.5
58

HKC
-CS05

8.7

45.5

44.1
47.4

HKCCS06

HKCCS07

8.6

8.5

Khu ĐT mới Tây Quốc Oai(TT Quốc Oai)

53

45.4
47.2

aQ 1³ vp

7

bmQ 2¹- ²hh

aQ 2³ tb
15m MNN năm 2013

10

25

35

P 2 nv

aQ1³ vp

24.5
31

40
43

P2 nv

39

QO -02 QO -01

YN4

YN1

7.5 8.36

8.1

5.0

xã Thạch Thán, Ngọc Mỹ

Yên Nội, Đồng Quang, Quốc Oai

0

1000

2000 m

Figure 4.11. Land subsidence in Quoc Oai town and neighboring areas (2008)

4.1.2. The causes of land subsidence
4.1.2.1. Current situation of exploitation groundwater.
The mainly water source to serve life activity and productions from
wells. Currently, many wells of the populations, organs and wells in the
industrial zones exploit water in limestone.

The

cones

lowered

of

groundwater level located in Quoc Oai town and neighboring areas as
Thach Than, Ngoc My communes and Dai Nghia town. The cones lowered

of water level coincides with area has the soft soil layer.
4.1.2.2. The cause of land subsidence
When groundwater level was lowered lead to change stresses in soil,
pore water pressure drops, and effective stress (stress caused subsidence)
increases to make deformation of ground and sunk down.


18
Lún - hồi phục do biến dạng đàn hồi
Lún không hồi phục vĩnh viến
do biến dạng không hồi phục

Tầng chứa nước

Tầng cách nước
(sét, sét pha)

Sự nén chặt của hệ thống nước ngầm
tập trung trong các tầng cách nước

Mực
nước

Các hạt cốt đất giới
hạn sự lấp đầy nước
ngầm trong lỗ rỗng

Sự sắp xếp và làm chặt
lại của tầng cách nước
cùng với sự giảm độ lỗ

rỗng và lượng nước
tích trữ trong lỗ rỗng

Thời gian
Suy giảm lâu dài mực
nước theo các chu kỳ
bơm hút nước ngầm

Figure 4:19. Inelastic deformation of aquifer

4.1.3. Relationship between Quaternary sediments with land subsidence
For sedimentary in profile type : included four sub-profile types.
- Sub-profile type 1.1 without soft soil layer, less affected by land subsidence.
-Sub-profile types 1.2; 1.3 and 1.4, has soft soil layer, affected by land
subsidence when the water table is lowered and depending on the thickness
of the soft soil layer.
For sedimentary in profile type 2: included four sub-profile types,
without soft soil layer, less affected by land subsidence
For sedimentary in profile type 3: included five sub-profile types, the
soft soil layer thickness varying from 10m to more than 20m, high affected
by land subsidence, especially uneven settlement.
For sedimentary in profile type 4 included five sub-profile types,
without soft soil layer, less affected by land subsidence
4.2. Features of ground collapse in the West area of Hanoi
4.2.1. The current status of ground - collapse
From 2006 to present, in the West area of Hanoi has happened series of
ground collapse during drilling wells


19

Typical location of ground collapse as Yen Noi village, Dong Quang
commune, km16, provincial 419 Quoc Oai town; Hamlet16, Ang Ha
village, Le Thanh commune and Team 6, Thuong village, Xuy Xa
commune (My Duc district). In the first 6 months of 2014 have occurred
three points of ground collapse at Le Xa village, Le Thanh commune, My
Duc district and in Yen Son, Liep Tuyet communes (Quoc Oai).
4.2.2. The causes of ground collapse
General features of the ground collapse as follows:
- The ground collapse occurs only when human impacts (drilling).
- The geological section has fine sand layer and soft soil layer.
- Limestone layer beneath was cracked (high fractures), somewhere has
karstic caves underground.
The nature of the ground collapse is due to fine-grained, and soft soil
layer were washed out and creating voids in the soil and destroy layers
cover above of the voids. Cracks (or underground karstic) act as path and
stores contained fine-grained material from above moved down.
4.2.3. Relationship between Quaternary sediment to ground collapse
x.Yên Sơn,
Quốc Oai

TT Quốc Oai

aQ 2³ tb
13.5
20

x.Xuy Xá
Mỹ Đức

x.Lê Thanh,

Mỹ Đức

7.0

12.5

aQ 2 ³ tb

9 .1

11

12.5

bmQ 2¹- ²hh

x. Hợp Tiến
Mỹ Đức

mQ 2¹- ²hh

10
13.7
18.7

18.5

26.5

28

30.5

aQ 1³ vp
aQ 1³ vp
40

44

P2 nv

48

¹-

h
²h

12

2

43

P 2 nv

aQ 1³ vp

T2a dg

35

48
Chú giải

Q
bm

8.5

21.6
24

25

38

3

aQ 2³ tb

4.0

4.0

10

amQ 2¹- ²hh

Yên Nội, Đ.Quang
Quốc Oai

39.3
40.8

38.8
39.7

karst
47.5
60

k arst23.3
2 5 .0

26.5
karst
34

karst
T2 a dg

43.6
46.7

60

Sét, sét pha màu xám nâu, vàng nhạt, dẻo mềm
- dẻo cứng
Sét m àu xám xanh, loang xám vàng, dẻo cứng,

Sét, sét pha, bùn sét pha lẫn vật chất hữu cơ màu
xám, xám đen
Sét loang lổ bị laterit hóa, dẻo cứng - nửa cứng

Cát mịn màu xám, xám nâu, xám ghi

Đá vôi màu xám, xám sáng nứt nẻ, đôi nơi có
hang karst ngầm

Fig 4:27. Combine stratigraphic at ground collapse positions in Western Hanoi


20
Most of the positions occurred ground collapse has fine sand layer and
soft soil layer in the geological sections (Fig4.27), bedrock beneath are
limestone, high fractured, cracked, some places have underground karstic.
4.5. Warning and proposed prevention solutions land subsidence,
ground collapse
4.5.1. Forecasts land subsidence
Results calculation of land subsidence in 2008, forecast to 2020 and
final settlement were integrated on the geological section
Độ lún do hạ thấp mực nước ngầm tại thời điểm năm 2008
S
(cm)

10.3

5

12

11

9.6

7

10 8.8

Dự báo độ lún do hạ thấp mực nước ngầm đến năm 2020
5.2

S
(cm)

13

14

16

13

21.5

1512

14

CHÚ GIẢI

aQ 2³ tb Sét màu xám nâu,
vàng nhạt, dẻo mềm
Cát hạt nhỏ mịn màu
aQ2 ³ tb
xám nâu, xám vàng
Sét, màu xám xanh, xám
mQ2 ¹-²hh
vàng, dẻo cứng
Sét, b ột lẫn hữu cơ màu
b mQ ¹ -²h h
xám, xám đen, dẻo chảy
2

32

Dự báo độ lún cuối cùng và thời gian lún do hạ thấp mực nước ngầm

aQ1 ³ vp

Sét loang lổ bị laterit
hóa, dẻo cứng

aQ1 ³ vp

Cát hạt thô vừa màu
xám vàng, chặt vừa

8.2
18

45.5

(năm)

mQ 2 ¹-²hh
aQ2 ³tb

Cao độ (m)

70

10
0

4.2

7.6
8.5

4.7
6.3

11.8

20

28.3
34.7

b mQ2¹ - ² hh

5.2
8.2
11.7

6.0

3.0

20

20

19.5
20.5

aQ1 ³ vp
P2 nv

HKB T-CS47
HKB T-CS46
HKB T-CS50
6.18 6.2

58

42.3

8.7

45.5

44.1
47.4

HKCCS06
8.6

HKCCS07
8.5

Khu Đ T m ới Tây Q uốc Oai(TT Quốc Oai)

53

MNN năm 20 00=2.5-3m

2.5

bmQ 2 ¹-²hh

18.3
21.2

36m

39.3
43.5

HKC

- CS05

145

11.2

12.0

15

45.8

5.96

7.6
11.7

6.2

-40
HKC -C S04
8.61

48
152

1.2

2.1

22m
-20

45

39

45.4
47.2

7

bmQ 2¹ - ²hh

aQ2 ³ tb
15m MNN năm 2013
10

25

aQ1 ³ vp

35

P 2 nv

QO -02 QO -01
7.5 8.36

xã Thạch Thán, Ngọc Mỹ

aQ1 ³ vp

24.5
31

40
43

P 2 nv

39

YN4

YN1

8.1

5.0

Y ên N ội, Đồng Quang, Quốc Oai

0

1000

2000 m

Figure 4.30. Section forecast land subsidence due to groundwater extraction from

Quoc Oai town to Dong Quang commune

4.3.2. Warning risk of ground – collapse
- Areas with high risk of ground collapse occurred in profile type 1 (subprofile types 1.1 and 1.4) and profile type 3 (sub profile types 3.2 and 3.4).
- Areas with high risk of ground collapse occurred in profile types has soft
soil in sub-profile types 1.2 and 1.3 and sub-profile types 3.1, 3.3 and 3.5
- The remaining areas of profile types 2 and 4 has no soft soil or fine sand
layers, less likely to occur ground collapse.
4.3.3.Proposed solutions to prevent land subsidence and ground collapse
Limiting exploitation of underground water, construct of the water
treatment plant and ensures high quality provide sufficient flow for
domestic service and manufacturing sector is essential and urgent.


21
Encourage peoples not to arbitrarily drilling. In case of drilling well for
short-term, they have to apply reasonable engineering science drilling, with
the assistance of the specialized agencies
52
26

54

56

58

thạch

24

60

62

64

66

68

q.ba đ ình

70

72

74

76

78

80

82

84

86

q . cầ u

TÔđƠẳ Ê

T1o tlTÊẵẩ

PRÊẩ ẵ

thất

4.2

PRÊẩ é

88
26

giấy

P2 nv

CƠ PÊẳ ắ Ô

q . đ ống đa

24

T1o tl

TÊẵẩ

3.4

22

2.1

2.1

2.3

T1o tl

TÊẵẩ Ê

4.3

ap Q

18

2.3

2.3

2.1

TÔơƠẳ Ê
ỉõTÊẳ é

PÔểắ

aQ29 tb

1.4

TÊéẩ Ô
TÊéẩ Ê

PÔểắ

18

Hà đ ÔN G

4.2 4.5

2.2
2.1
a p Q 18 -9h
n

2.1

2.4

16

PÔểắ
T1o tl

TÊéẩ Ô

4.2

than h

1.3

14

trì

2.1

TÊéẩ Ê

2.1

2.4

12

TÊẵẩ Ê

12

c h ơ4.2
n g mỹ

2.1

TÔơƠẳ Ê

aQ ẻẳ Ô

10

2.2

than h oai

TÔơƠẳ Ê

TÔắ Ô

08

q. h o à n g

TÔắ Ê

14

10

22

20

2.1

TÊéẩ Ô
TÔơƠẳ Ê TÊéẩ Ê

TÊéẩ Ê

aQ ẻẳ Ê

aQ29 tb

4.4

3.1

4.2

TÔơƠẳ Ê

16

xu â n

TÊéẩ Ô
TÊéẩ

3.2

q u 1.1
ốc oai

2.1

q . thanh

hoài đứ c

2.4

2.3

TÊéẩ Ô
20

q . hai
bà trng

4.4

PRÊẩ ẵ

TÔđƠẳ Ê

2.2

4.1

TÔắ Ô
TÔẩ ẻ

08

2.4
2.2

06

06

3.4

TÔẩ ẻ
04

T1o tl

Hò a

00

bì nh

TÊéẩ Ô

02

dpQ
TÊẵẩ Ô
TÊẵẩ Ê

2.1
02

TÔẩ ẻ

00

TÔắ Ô
1.1-1.4 Khu vực bị đang bị lún
3.1-3.5 và có nguy cơ xảy ra lún mặt đất
TÔắ Ô

Khu vực ít có nguy cơ
xảy ra lún mặt đất
Khu vực ít có nguy cơ
4.1-4.5
xảy ra lún mặt đất

3.3

94

98

3.2

2.1-2.4
96

04

TÔắ Ô

4.1 4.2

Chú giải

98

th ờn g tí n

96

TÔắ Ô
TÔắ Ê
TÔắ Ô

94

3.3
92

TÔắ Ô

Khu vực núi đá

92

3.2

3.4

mỹ đứ c

90

T2_3 sb1

Phụ hệ tầng dới - hệ tầng Sông Bôi

T2
T2nt
nt

Hệ tầng Nậm Thẳm

T2 a dg

Hệ tầng Đồng Giao

T1 vn2

Hệ tầng Viên Nam
Phụ hệ tầng trên

TÔắ Ô

ứng

3.5

90

hòA

88

88

aQ29 tb

TÊẵẩ Ơ

86

82

86

TÔắ Ê
TÔắ Ô

84

TÔắ Ô

3.5
84

TÔắ Ô

Q Ô
TÔắ

TÔắ Ô

Q

82

TÔơƠẳ Ô

T1 vn1

Phụ hệ tầng dới

80

TÔơƠẳ Ê

TÔắ Ô

Q

T1 o tl

Hệ tầng Tân Lạc

P2 nv

Hệ tầng Na Vang

3.5
80

TÔắ Ô

TÔắ Ô

TÔắ Ê
pQ

78

78

76

76

Đứt gãy
74

TÔắ Ô

Tỷ lệ 1:50.000

Hà

1c m trên bản đồ bằng 500m ngoài thực tế
52

54

56

58

60

62

64

66

68

70

72

74

76

78

80

82

na m
84

86

Figure 4:32. The prediction map of risk on land subsidence
in the West area of Hanoi

74

88

mai


22

Figure 4.34. The warning map of risk on ground collapse
in the West area of Hanoi

Encourage and require the implementation of strategies to use water saving.
Some of measures necessary to apply include:
- Management of the investigation, geological survey, hydrogeology more
stringent, fully assess the distribution characteristics of underground karst


23
- For construction: compliance with standards and processes in karst areas
- Upon detection of karst cave must have the appropriate remedial. For the

high loading constructions, applied solutions pile foundation. Avoid karstic
caves cases are not detected during the survey, but reappears when
construction and strict management of different human activities impact on
the ground in those areas at high risk of land subsidence .
CONCLUSIONS AND RECOMMENDATIONS
From the research results of the thesis, some conclusions are referred as
follows:
1. The Quaternary sediments in the West area of Hanoi includes 10
sequences.
- Alluvial-proluvi sediments (apQ12-3 hn) and alluvial channel (a (c) Q12-3
hn) of Hanoi formation;
- Alluvial channel (a(c)Q13 vp) and alluvial flat plain (a(f) Q13vp) of Vinh
Phuc formation;
- Alluvial-marine (amQ21 hh), bog-marine (bmQ21-2 hh), marine (mQ21-2 hh)
and alluvial-bog (abQ21-2 hh) of Hai Hung Formation;
- Alluvial channel (a(c)Q23tb) and flat plain (a(f)Q23tb) of Thai Binh
formation
2. Quaternary sediments in the West area of Hanoi is divided into four
profile types with 18 sub-profile types. The profile types 1 and 3 with the
participation of the soft soil layer, high risk occurring subsidence and
ground collapse. The profile types 2 and 4 without the participation of the
soft soil layer, less effected to land subsidence and ground collapse.
3. Land subsidence occurred in places with soft soil layer in the geological
sections (distribution of sedimentary with profile types 1 and 3) and the
effects of lowering water tables. In Quoc Oai town and adjacent, the water
table was lowered to 35.5-36.5 m depth. At the time in 2007- 2008 the