Cấu trúc và biến dạng bãi biển đường 14 đồ sơn hải phòng tài nguyên và môi trường biển,

T ii.i n g u y e n

10. T ai

v ii. M 6 i t r u i r n g b ie n .

lie u

ve baa

m oi

N guyen

tv

C hu

III -ZYXWVUTSRQPONMLKJIHGFEDCBA
1996

T ( ip

hoa

phan

H 6 i,

dao

Q uang

Pham

dai

s6 ket
yen

qua

bo

ung

6 Phan

dung

tu

lie u

v ie n H a i

duong

tia « D u e T h a n h ,
N f? u y e n H u u

v ie n

th a rn

hoc

N guyen

Le

tro n g

ta i H a i

C hu

tru e

v a b ie n

dang

bai

b ie n

duong

D in li

cu.

T ran

tr a «

Due

T h q . n h , T r f in D ln h

N guyen

Due

C u , D in li

V a ll

Pham

Hudn,

Lan,

ph6ng

v a ta c

to a n

dong

h e th o n g

hoc

trie u

tro n g

Ldn ,

Q uang

Tudn

H ai

Phong

tu a « ,

V :y , N g u y e n ru

Phuong

Hoa,

T h i K im A n li

d o g io , d o n g

lu u

nho va nhung

vung

nuoc

song

nuoc

yen

be)

b ie n

115
Pham

14. Phan

vung

nuoc

tro i

s in h
bang

th a i

b ie n

phuong

N in h

phap

T h u a n -B in h

th a n h

T huan

phan

V a ll H u t in

tro n g

15. D ac

d ie rn

tra m

ric h

phan
bai

b6

trie u

to n g

ham
cua

v u rig

lu u

lu o n g

song

B ach

122

huynh

s u lfu a

V e in

d ie m

th u y

h6a

vung

b ie n

q u a rt

D ang

128

dao

Co

do

tro n g

d a u tro n g

th o i

g ia n

nuoc

th a n g

b ie n

yen

b c 1 m ie n

T ru n g

duong

tro n g

tra m

tic h

dam

pha

qua

duong

tin h

cua

ro a n

th u c

nang

suat

v ~ lt n o i trn n g

so cap

h~ dam

va

N am
147

T am

V an Luong

G ia n g -C a u

m o t s 6 h ie u
pha
Do

338

142

o te u

1 2 /1 9 9 4 -0 1 /1 9 9 5

N guyen

19. K et

C~

N in h )

Van

V ie t

Pham

D in h

Due

T o (O w in g

Luu
17. N ong

sat

tro n g

N guyen

16. D ac

rn u a

c h in h

La

18.

103

ca.

tta u

N guyen

Q uang

hoan

c a c v in h

L tin ,

V (IIZ

D in li

Son,

N guyen

13. M o

93

V an H uy, N guyen

V a ll

Pham

Do

14,

cuu

Phong

N guyen

1 2 . C tiu

T ie u

Nhu

n g h ie n

H 6 i,

C u, N guyen D ue

8 9 WVUTSRQPON

tia « D u e T h a n h ,

T rung,

T r a n D in lt L d n ,

N guyen A n,

11. M ot

L o n g GFEDCBA
Vy

B ach

am

qua

G ia n g -C a u

T r Q llg

eu«,

H ai

154

DUe Cu .

d in h
H ai
D O ( ln

163

eo

Tiii nguy€n

vel M 6i truirng

bien.

T4p III

• wvutsrqponmlkjihgfed
1996

im ages have been applied efficiently to coastal zone studies ill the H aiphong
Institute oj O ceanology. Though the interpretation has been done sim ply with
visual analysis, its results. have proved QPONMLKJIHGFEDCBA
1 0 be well for the coastal zone study
and m anagem ent.
Rem ote sensing data application are to estim ate coast
present status, landuse and waters, to investigate and inventory natural
resources types oj wetlands, m a n g r o v e s , etc , and study coastal ongoing
processes, dynam ics of coastal erosion and deposition, channell deform ation,
inlet closing or m oving processes o] coastal lagoons as well as sedim ent
transport. From the applications, however, som e difficulties were em erged as
a low level of interpretation capacity and facility. fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

*
*

CAU TRUC

VA BIEN

*

D~NG

BAI BItN

DO SON, HAl PHONG

DUONG

14,

•

Triin D lic Thanh, Trail D inh. Liin, Nguylll H tiu Or,
Nguyll! Chu uo; Nguylll D lic C I,I" , D inh Vall H uy,
Nguyln Q uang Tuiin, Pham Van H ulin", Pham Van VJ' •• ,
Nguyln TIl; Phtrtm g H o a , Nguyln Thi Kim Anh,
I.

MO Dlu

Bai bien Duong 14 keo dai 4 km ap ngoai de Carn Cap 0 phia tay nui
Doc, D o Son, Hai Phong, narn d vung cua song hinh pheu c6 thuy tr ieu
bien d¢ Ion [6]. N o co vai tro quan trong lam dern chan cho mi)t doan de
xung yeu bao v~ true tiep cho 1.600 ha khu kinh te rnoi bao gorn ca khu
che xuat Duong 14, va phong h: cho mot vung dong bang rong Ion voi
khoang 150 km2 va 20 van dan. Tuyen de luon (1 trang thai xung yeu lien
quan den qua trinh x6i 10 bai phia ngoai, Vi v~Yt nghien

dang bai bien

d day ngoai

y

nghia

khoa

cuu d IU true, bien

hoc lam sang t6 nguyen

nhan

va

xu the bien dang bai quan he voi t6 hQP cac yeu t6 dong luc cua mot vung
• Cong

trinh

nay la

kel

qua c u a d~ ta i Ma s6 7.3.1 thuoc

chuycn

nganh

cac

khoa hoc

vc Irai dill 1996-1997 .
•• Dai hoc Qu6c

gia Ha NQi.

103


va M 6i truirng bien.

Tiii nguyen

c6 thuy
tuyen

trieu

bien

d(l lon va c6 che

de qua n trong

C h u o n g tr inh

I(,)i cho

Tiip /11 - 1996

cua Hai

d(l gi6 rnua,

Phong.

Xin chan

n g h ie n c u u c o b a n cap

tac gia tap hop

t~lP the

tr inh nghien

con

thanh

gap

N h a n u o c dei tao

xu Iy phan

tich

phan

bao

earn on Ban

ve rnot

nhiern fedcbaZYXW

chu

moi d ie u k ie n thuan

ta i lie u va hoan

thanh

cong

cuu nay.

II.wvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
TAl LIE;u vA PHUONG PHAp lkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Bai viet

ph an tich

nay

Ul ket qua

nghien

va t~lP h o p so lieu

dieu

Hai Duong

Hoc t~li Hai Phong,

rnoi trunng

dia

chat

yen

hien

sat rmrc d() hoi tu de danh
Hai''

narn

1993,

Carn

- Narn

1992-1993,
14-Do

"Nghien

Trieu

SOn - Hai

Phong''

nhieu

narn

narn

cua

1990-1993,

cua d a p Dinh

sa boi lui.)ng

hoc

thuoc

sat

tac gia tre n co so xu

"Dieu

thuat

ky

de tai dip

Nha

nuoc

hen

Hai

tuyen

ve

tra

sat

khao

ca Ngoc

d6i vdi vung

ding

V~lO

bao

vo

Phong''

de

KT.03.]

Iy,

vien

Phan

tra khao

kha thi cua viec xay dung

huong

den

cluing khoa

"Luan

khan

Phong"

gia tinh

quan

t~p the

biet la C~lC de tai "Dieu

d~c

anh

cua

tra

Hai

cuu

lien

cuu

cua
narn

bai

Duong

4 do Vien

Khoa

hoc T h u y I<)i Ouoc gia chu tri. Cac so lieu khao sat quan trac duoc su dung
ban gorn:

tai lieu

cua

Vien

Khoa

cac

narn

198]-1983

tuc

ngay

]/10.000
1/1.000
(cua
gorn
10

va cac

V~I

narn

1980-1983
Ic)i Hai

the

tram

h~ ban

phuong

bien

tich,

di\

phan

tich

hinh

thai

dong

toan

tren

may

tinh

du duoc

lap

Mung

sat va nghien

cuu

van

lien

tham,

lai va the

tich,

phan

tich

phap

thuy thach

cau

bai,

phan

tich
cat

1981-1992.

qui pham

phan
dong

bun

(ty I~ 1/30.000)

narn

dao

14m

true

150 mau

bay

cac

d(l sau

tai lieu

Cl1U t h e o

vien

tich

dong

nghien

va chong
muc

nuoc,

luc va mo hinh

su dung .

.

tich m:)t bai.

hop

trong

tich

1. D:)c die'm cfiu true va tram
t6ng

C { IC

m {IY

phan

luc, phuong

bai den

v6t nang,

cac anh

cuu

tang

tren

di day.

KET QUA KHAO SAT vA NGHIEN

Dja

104

Chao

thuy

Phong

tr ac dja hinh do ti I~
dac I~p 1~1i3 mat cat bai

2m nghien

khoang

1938,

tra khan

ban

mau

20 mau

phap

ghep

III.

dia

thu

narn

Spot.

dieu

phuong

trac

tv

do

Landsat,

phap

(]981),

nghiern

7 tram

song

li~u

trac

den

trac

Hc,)c tai Hai

trac

khoan

7 16 khoan

tai lie u quan

Duong

cac tai
tai lieu

va 1992-1993,416
thuc

Dau,

tai lieu -quan

(1992),

Phong).

vdi 7 tram

Hon

vie n Hai

1992-1993,

1/5.000

a nh ve tinh

Cac
Cl1U

trong

cac

van tram

1992-1993,

V~I

90 mclu co hoc

lung,

thuy

T h u y IQi va Phan

dern

So Thuy
cat

hoc

(1981)
narn

2 mat

khi tuong

Holoxen

vung

trieu

khu vue bai hien

day 7-12m,

gorn


T a i n g u y e n v a M 6 i lkjihgfedcbaZYXWVUTSRQPONMLKJIHG
truirng b i e n . T ~ p III -wvutsrqponm
1996 fedcbaZYX

4 lo p tu d u o i le n [5 ].

Lop 4: bun cat bot m a u xarn, xarn n a u , xarn den n g u o n g o c ho darn ven
bien, day 3-4m, xuat hien () be mat O,4-0,5m dudi OmHD (Om hai do).
Lap 3 : cat n h o m a u xarn xanh n g u o n gdc bien, c h u a n h ie u v o than mern
bien, ay 2-3m, be m a t u o n lu o n d dQ s a u O,5-2m so v o i m a t b a i. P h u tr e n
lop nay la lop bun set rnau n a u , cat xarn n a u hien dai, tuoi thanh tao k h o a n g
1-3 nghin

narn truck.

Lop 2: bun cat bot deo quanh xarn xanh, day khoang O,5m phan h o han
che trong bai trieu su vet giap phia bac va nam dai bai cat bien, be mat
xuat hien 2,4m/Om HD, tudi thanh tao khoang 1-2 nghin narn truce.
L(1p 1 : bao gorn cac tram tich hien dai nhat, dang duoc tich tu, co thanh
phan va nguon goc dong' luc khac nhau.
.
Lop 1 a : bun bot mau xarn nau, tich tu d bai trieu thjip, duo] trieu, phu

true tiep len lop 3 chi day khoang 10-15<:01 co xu th e hi bao mon thay the
bang v~t lieu cat bai boi tu Old rong.
.
Lap Ib: bun bot mau xarn, day I-2m,
bai ngap

trieu

nguon

lay, narn d

cao.

Lop l c : la lop cat nho xarn nau, day O,l-lm,
lop mat bai cat bien hien dai.

o

g6c bai trieu
la tha nh phan

chinh

cua

Lop J d : bun set bot, bun bot mau nau, nau himg, day O,4-0,5m tich tu
bai trieu thap phia bac dai bai.
Lop 4 co tuoi Holoxe n sorn giua (OIyl-2),

m uon

cac lop 3,2,] co tudi Holoxen

(OIy3).

Mat cat cau true bai the hien tren hinh 1. B e mat beli rong (trung
1.000m),

thoai

va gnn s6ng manh.

binh

Dinh bai co dQ cao dat 2,5m, phd bien

1,8-2,2m/Om
HD, eo noi chi 1,6m/OmHD,
chan bai thuong c6 dQ cao
O,4-0,5m/OmHD.
Cau true co ban cua bai chi gorn 2 lop (trong pharn vi tu
ngang rnuc OmHD tro le n ) , Lop duoi (lop 3) la lop cat bien co mau xarn
xanh, lop tren (lop l c) la cat nho xam nau, hien dai. B e mat ranh gidi giua
hai ldp gon song c() d(> cao thay d6i O,5-1,5m/OmHD. Trong cac lop cat
xarn nau co cac thau
Cat lop
0.14-0,15mm,

kinh mong bun bot.

•

m~t bai bien hat nho, gia tri Md t~p trung trong khoang
giarn dan tir 0,16mm 0 sat ria trong bai thanh O,138mm d

ngang muc 1,lm/OmHD.
the a muc trieu

trung

Thea
binh

mat cat doc bai, gia tr j Md 6n d jn h oO,14mm

(MTTB)

va giarn tir 0,14mm

v e hai phia con
105

.


T i l i n g lly e n

v i l M 6 i t r u i r n g lkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
bU n. T ( i p III -wvutsrqponmlkjihgfedcbaZYXWVUTSRQP

1996

0,13mm thee duong 1,1m/OmHD. Thanh phan khoang v~t nang bai chu yeu
gorn Hoblen (1-2,5%). Limonit (4-8%), Silimanit (2-4%). Tuamalin
(1-2,5%), I1menit (0,5-1%), Zircon (0,1-0,3%). Epidot (1-2%). Khoang v~t
'nang phan bo thanh dai voi die mire ham IUQng khac nhau. Tu MTTB
(1,86m/OmHD) trO len 10-15%, tir MTTB toi rnuc trieu thfip nude kern
(1,1 m/OmHD) 5-10% va dudi muc trieu thtip nude kern 5-10%. Dac diem
phan bo tram tieh va khoang v~t eho thay huong tac dong cua nang IUQng
s6ng tao lee su phan tan boi tich ra xa bo va ve hai phia cua dai bai bien.
2. D~c diim bien dang bai

Dai bai cat bien hien dai dai khoang 4km, rong 320· 760m, trung binh
520m. Neu tinh ca bai trieu thap phia ngoai bai, chieu rong vung trieu dat
1000-1200m. Be mat bai nghierig thoai tu fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
ta y sang dong voi dQ d(le
0,002· 0,003 va tir tay bac xudng dong nam voi dQ doc 0,001· 0,0015. DQ doc

fO O

-2

'"

•

Om
,

100

!

J l. M N C N

C J .l

-2

Hinh 1. Mat cat cliu true bai Dltilng 14. Hai Phong ,

106

l

B ,6 t

S it


Tai nguyen va M {ii truirng bien. Tt)p III - wvutsrqponmlkjihgfed
1996

bai Ion nhat 0 dai rong

100m ap bo, trung binh 0,012, sau d6 la 0 phan

bo

ngarn 0,004-0,007.
Hien tai, toan hO dien tich vung trieu rong 1023 ha, trong d6 dien tich

b o cat nho va hot lon lien quan den tac dong cua dong song doc bo
phan fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
450 ha. Phan bridien
tich vung trieu theo cac mire dO cao nhu bang 1.
So sanh thoi gian 1981-]993, dien tich vung trieu Duong 14 tang 257
ha. Trong d6, dien tich duoi T\1TTB tang .270 ha, con dien tich tren MTTB
giarn

13 ha (bang

Phan

Z),

.

dien tich tren MTTB

bj giarn J 3 ha duoc xac dinh la hieu so dien

tich xoi 1 6 bai cat bien 23 ha va boi tu cac bai trieu

]°

eao trong

khuvuc

la

ha. Phan tich cac mat cat trae IUQng lap lai (h. 2) cho thdy sau ]2 nam,
trong khoang bai 300-400m sat bo, mat bai bi ha thap d() cao trung binh
O,3-0,4m,
cue dai 1mung
voi toc do ha thtip 2,5-3cm/nam,
cue da i
8,3cm/nam.
Phan noi cao tren MTTB cua bai bien thu hep dang ke tit
IOO-150m nam 1981 chi con 50-60m van narn 1993, ung voi toe dQ xoi 10
dich lui 4,1-7,5m/nam.
Toe dO x6i 1 6 kha lon, nhung qua trlnh x6i 10 khong
Bang 1
Phan

be) dien tich vimg trieu

DlJong 14 theo cac mile de) cao

=~~~d~

Doi tricu

~~~;~R_tiCh

(ha)

Cao

Tren

Thap

1,86-1,1

273,9

1,1-0,40

351,3

1,86

129,1 .

0,40-0,00
261',8
----_._---'----_._-----

Bang 2
Bien d(ing di~n tich vung trieU DlJong 14.

Nam
1983

D ic n

tich dt10i MTIB

Di¢n tich trcn MTIB

Tong

1993

624
894

142
J29

766
1023

can hang

+270

-13

+257

107


va

n g u y e n lkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
M 6 i t r u i r n g b ie n . T ( l p III -wvutsrqponmlkjihgfedcbaZYXWVUTSRQP
1996

Tai

tao fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
v a c h do mat bai thap v a bo de bien xay d u n g narn 1981 tren
cat tv nhien tro thanh vach nhan tao chju su pha huy cua song.

than

de

Ket qua trac dia I~p lai cho thay tren cac mat cat sau 12 nam (h. 2),
bai bj xoi 10 bao man tit vi tr i duong d~ng cao 1,0-1,1 m/OmHD tro len va
co the coi duong 1,1 m/OmHD ung voi muc trieu thap nude kern la duong
phan gioi xoi 10 - boi tu bai. Trong khoang dO cao 1,1-0,4m/OmHD,
bai
tuong doi on dinh va it bj bien dang do bbi x6i. T.it khoang
duong
0,4m/OmHD

cho den dO sau 1m !a phan

tich tu rno rong.

Vi vay, duong

OmHD duoc mo rong Ian ra phia bien. Trong thoi gian 1980-1981,
song cat phat trien
narn 1992-1993

co nhung

lien tiep, xen voi cac ranh trOng tren mat bai. Cho den

cac song cat bj san phang hoac giarn di rura chieu cao. Dong

thoi cac ranh trOng currg hi vui lap hoac can lai rat n o n g , Nhu vay, trac
dien bai tro len thoai hon va don gian hon. Muc dO ha thap mat bai cung

J ~
.~ ..•..••.

-..:::,'

- '- . _ . _ . ,

2

so.

Om

g /f9 9 3

.

2
SO

Om

f

Om HFJ

2
i

,

'~ '~

s~

01[1

Mjtea·'

_so,.,.;.

_-

~4~

50

1 ----

1<2

_ -.

- --:

.'

-

.

----------------------

.9 1 { .9 .9 .1

O m H f)

Minh 2. M<)t cat ngang bien dang bai

108

D~bng

14, Hili Phong,


Tai QPONMLKJIHGFEDCBA
nguyen
va M lii truirng bien. T~p III - wvutsrqponmlkjihgfe
/996

tang dan tit hai phia

Ngoai nhung

V~lO

khoang

giua dai bai.

bien ctoi then xu the dai lau, con thay nhung

bien doi ro

r~t theo mila.fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
V e mila gin dong nam, dong song doc b o d i c h u y e n b o i tich
doc bo ve phia tay bac lam cho bai phia nay phat trien ro. Ve mila gio
dong bac, nguoc lai khu vue bai phia dong nam ph at trien. Vao cac mua
g to c h u y e n
tiep thinh h a n h sting h u o n g dong v u o n g g6c v o i b o , then c h ie u
doc bai phat trien cac " t" e s to n cat tao nen hinh thai 1L1c)nsong cua phan ria
cao b a i, c6 d a n g rang IUQc. Khi s o n g c h u y e n h u o n g th in h h a n h sang dong
b a c h o a c dong nam, cac feston cat b ] b ie n m a t.·
3. Cacnhfm

tei"gay bien

dang

bfii

- Tdc dong nluin sinh: tr u c e day d a i b a i bien n g h ie n c u u k h a Clll d jn h
va la m~t phia ngoai cua dai de cat bien. Sau cong trinh de Duong 14 hoan
thien narn ] 981 chay tren dai de cat, bai bat dau bi bien dang manh then
huong
x o i 1 c '1p h a n
cao, b<)i tu p h a n thtip. Trac d ie n ngang bo-bai b ] rut
ngan ct(>t n g o t va song p h a n x a tao th a n h dong n a n g lu o n g doc bd di c h u y e n
bun cat ra khoi khu bai.
"

Dap Dinh

Vu

hoan

th a n h

cung

vao

nam

1981 gay ra

nhung

bien

dong

phirc tap [4], trong do co viec di c h u y e n cat d cua Nam T r ie u v a o b6 sung cho
khu vue V~I g6p phan boi lap luhng van ben ca. Ngoc Hai [5]. Ket qua tinh the
bi x o i 16 40.000m 3 /nam,

tich cho th a y phan bai tren d u o n g 1,lm/DmHD
3

trong

to co s u b 6 sung cat dang
ke van khu vue. Hang narn con nguoi khai thac khoang 3D.OOOm 3Celt tai khu
vue cOng gay anh huong dang ke den bien dang bai.
khi p h a n d u o i dUdng nay boi

Lien

quan

den

cac muc nuoc

1,86 - 2,4m/OmHD,
0,4m/OmHD.

T ro n g

kha

on

chung

5 D .0 0 D m /n a m ,

d jn h

tr ie u ,
()

1 ,1

d ie u k ie n s o n g n h o ,

thtiy rang
-

bai

0,4m/OmHD

bi

1 c '1(1 k h o a n g

x6i
va

htli t1,1 c 'j

duoi

d~lO d o n g tr ie u Io n dc1 t ~ 1 0 n e n b a i

thoai rong, thtip va c6 tinh phan ddi dong IVc.
- D ong cluiy:

d o n g c h a y tr in g h o p

do d o n g trieu q u y e t dinh,

dong song

h u o n g den de) sau 0,5m. Dong c h a y x u o n g h u o n g dong nam
12 - 14 gio, t{'lc d(> cue dai 35cm/s, dong chay len huong tfly bac

doc bo anh

keo dai

keo dai 10 - 12 gib, toc de) cue dai 42cm/s. Tinh then mat cat tit bil den
de)

sau

1m, moi narn

xuong phia dong

- Song:

co

308.000m 3

nun cat

lo

lung di

chuye

n

doc

yen

bo

nam [5, 7].

Song () tram

Hon

Dau can trung

binh 0,5 - 1,0m, cue d~li Sm.

Mac du khu vue hcli nghie n cuu co toc de) gio kha Ion, trung

hinh 6;Xm/s,

109


Tai nguyen va M {ji QPONMLKJIHGFEDCBA
tr u im g
bien. T(lp III - wvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC
/996

C\fC dai 45m/s trang bao nhung dia hinh kha kin, co nui Doc che chan
d(> cao song khong Ion, trung binh 0,3 - 0,4m. DO cao song Ion nhat
nhan

n&h

ghi

duoc la 0,8m VaG mua gio dong bac, 1m khi co bao VaG mua gio dong

nam [5, 9]. Khu vue chiu anh huong cua song huong dong bac va dong nam
voi hai rnua gio, anh huong cua song huong dong bac quyet dinh hon doi
voi di chuyen boi tich doc bo ung voi huong dong tong hop ve phia dong
nam.
Bung 3

nam muc m1{Je d~o d(mg qua fedcbaZYXWVUTS

Cae mue nUlle trieu va so ngay trong

I S6
D ()

ngay m uc

nuoc

dao dO ng qua

cao (m/OmHD)

'(1992)
"

Trieu

binh
T r ie u c a o n u o c k e r n trung
Muc trieu trung binh
cao

nMit trung

3.6
b in h

•

23

2.4

246

I.R 6

36.1

T r ie u

th a p n u o c k e r n tr u n g b in h

1.10

245

Trieu

thap

0.40

67

n ttdc i:ttong

Ket qua tinh
m o h in h C E R C

Trang

toan

trung

binh

,

dong

boi tich doc bo do song duoc

Q

202
,

thuc

hien

theo

[2 ]:
=

x

10 6 h 0 5/2 f(cosa

0

)1/4sin2a

0

do:

ho va a o la dt) cao va goc hop voi duong
f la tan xuat trung binh nam cua song.

bo cua s6ng.·

2.02 la he s() thuc nghiep vung bo cat thoai, d(> doc nho, duong bd thang.

Cac dac trung
quan

song d day dU<,1Ctinh tu gio co kiern dinh theo

trac cua Vien Khoa

vien Hai duong

hoc T h u y IQi qudc gia (1979,

hoc tai Hai Phong

(1990,

ket qua

19S4)" va cua Phan

1993). Song Ion nhtit d~ tinh co

dO cao O,8m ung voi gia trj C\fC dai da quan trjic duoc cua song gio dong
bac, Cac muc nuoc duoc dua van tinh C() gia tri 3,5m; 1,S6m va 1,lm/OmHD,
ket qua tinh tren

l(lp trinh

Bun cat di chuyen
gio mua

110

dong

may tinh dU~1Ctrinh

bay d bang 4.

xuong phia dong nam do song lien quan chu yeu den

biic. Bun cat di chuyen

len phia tay bac do song lien quan


Tai nguyin vii M 6i QPONMLKJIHGFEDCBA
tr u ir n g
bien. Ti)p III - fedcbaZYXWVUT
1 9 9 .6 " wvutsrqponmlk
!

,

chu yeu den gio mua dong nam. Tong IU~1ng bun cat di chuyen do"'-d6ng
song (Ogr) 8596m 3 /nam va can bang hoi tich +6247m 3 /nam
di ve phiadong
nam. Day la IUQng cat do song pha h u y b o va di c h u y e n can k h a c so vdi
thuc tien vi chua tinh duoc het cac yeu to khi tuong th u y van d~c biet, bat
th u o n g
vi d u n h u b a o mdi n a m a n h h u o n g 2 - 3 c o n v a n u o c dang trong
b a o . Tuy n h ie n k e t qua cling the h ie n r6 xu the can bang v a tinh p h a n doi
dong luc cua bai. Bun cat di chuyen Ion nhfit 0 khoang
de) cao 1,1 _
1,86m/OmHD
irng voi phan bien dang Ion nhtit cua bai.
Bdng 4
Luu Itlc)llg bun cat di chuyen

dec bai DtliJng 14(m 3 /nam)

Muc nuoc (m)

3.50
1.86

Xu6ng

phia d o n g narn (Ort)

.

1.10

Len phia

lay b a c (QIt)

1799
4275
1279

593
465

7371

1124

66

,I

Tong cong:

NhOng ket qua thuc nghiern cat di day cung minh hoa cho tinh toan
then mo hinh [5]. Thuc nghiern dU~1Ctien hanh 1 ngay dern tren 3 mat dlt
vao thang 9/1993 trong dieu kien song cao 0,3 - 0,5m. Ket qua cho thfiy
v~t li~u di day tr e n b a i 0 k h o a n g 0 - 1,1m/OmHD k h o n g dang ke. Cat di
day chu yeu tit 1,lm/OmHD
den sat hd, luu IUQng tang dan tit phia bac
x u o n g phia nam. Trong d ie u k ie n khi tu o n g th u y van b in h th u o n g , m oi narn
chi co 756m 3 cat di c h u y e n d o c b a i ve p h ia - dong
thuc nghiern

eao eua 'm uc nude h ie 'll: Su dang
yeu to quan trong gay x6i 1 0 bb bai. Bai Duong
hien sut ha trong kien t<;10hien dai [1]. Ket h o p
chan tinh c6 qui mo the gioi, rnuc nuoc khu
2,24mm/nam
trong may chuc narn qua tai tram
Ap d u n g cong th u c 'B r u u n de xac d in h toc do
cao muc n u o c [3].
la
- su

nam.

Dang

tiec n h u n g

khi co bao hoac song Ion chua duoc thuc hien duoc.

dang

cao cua muc nuoc

bien

la

14 narn trong khu vue b ie u
voi su dang cao muc nuoc
vue dang cao vni toc de)
do hai van Hon Dtiu [8].
x6i 1 0 lien quan den dang

X =h

111


Td.i nguyen

va M iii QPONMLKJIHGFEDCBA
tr u im g
bien. T~p III - wvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFED
1996

X: Tdc do xoi Il) bo, bai (rn/narn)

I: Chieu

rong trac dien bai bi bien dang.

a: Tdc dO dang

cao cua rnuc bien.

h: Do sau CIJCdai 'bien doi v(it lieu tram

tich lien quan

bien clang bai.

G ia tri a duoc xac dinh 0,0024m/nam,
cac ket qua khao sat cho cac gia
trj trung birth 1= 2000m, h = 1,lm (do sau sa voi OmHD)fedcbaZYXWVUTSRQPONMLK
+ 1,86m (vi tri
MBTB) = 2,96. Ket qua tinh cho X = 1,32m/nam, chiern 17 - 32% gia tri
toc d(l xoi 1 0 thuc te cua bai bien.
4 Du bao
QuA trinh bien dang bai DU<1ng 14 Do Son van con x a y ra manh me
theo hudng xoi W, bao men ha thjip phan be mat narn can tren muc trieu
thfip nuoc kern (1,1 m/OmHD) va boi tu mo rong phan thap b a i de tiep tuc
qua trinh san bang trac ngang bai. Thea mat cat doc bai, mac du co su
phat trien luan doi theo mua gio 0 hai phia, nhung xu the chung bai phat
trien ken dai xuong phia dong nam. Dai bai sat de tiep tuc b] ha thtip va
de xung yeu vi narn tr e n n e n cat v a kh6ng c o gia co m o n g . Thea xu the
dai lau, bai cat bien (heach) co the tien hanh bai trieu cat (sand tidal flat).
IV.

KET LuAN

Duong 14 k h a d o n g ia n , lo p d u o i la cat n h o xarn xanh
day den 3m, chua nhieu vo than mern, lop tren tao b a i hien dai la cat nho
xarn nau day den 1m. Ranh gioi giua hai lop la be matgon
song co dO cao
0,5 - 1,5m/OmHD. M~t b a i hien dai IU<.)nsong thoai, hinh thai va thanh phan
v~t chat (co hoc, khoang vat) co tinh phan ddi n ) ret lien quan tdi cac muc
hoat dong d o n g cua th u y trieu c o c h e d(l r o a n n h a t dell, bien de) Ion.
C a u tr u e b a i b ie n

Trong vong 12 narn (1981 - 1993), bai bi xoi )() thu hep tv mire do cao
1,1 m/OmHD trc') len va boi tu rno r o n g tv mire cao d(l nay tro xu6ng then
h u o n g san bang tr a c d ie n ngang. Tinh th e o d u o n g m u c bien trung b in h trd
len, bai bj thu h e p 23 hec-ta, toc do xoi 10 lui 4,1 - 7,5m/nam, bao mon he
mat 2,3 - 3,Ocm/nam.
SIJ hien dang bai la ket qua cua nhieu yeu t6 nhan sinh, thuy trieu, dong
chay, song va su dang cao muc nuoc. Tac dong con nguoi dap de rut ngan
tr a c d ie n h<1 la n h a n t6 k ic h p h a t gay b ie n d a n g hai then h u o n g xoi 1 ( \ C h e
dO dao d o n g th u y tr ie u a n h h u o n g s a u sac den tinh p h a n ddi trong b ie n d a n g
bai: xoi 10 kha manh l) muc tren MBTB; x o i ) ( ) manh l) muc MSTS - muc
trieu thap nuoc kern; k l,~ on dinh l) muc muc trieu thfip nuoc kern - ITIlJctrieu
112


T u i lkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
nguyen va M 6 i truirng h i t n. T ( i p / 1 1 - J 9 9 6 wvutsrqponm

thap nude cuong va hoi tu d mire muc trieu thap nude cuong cho den phan

duoi trieu. Dao dong th u y trieu bien do Ion trong ngay la nhan to quan
trong phan tan hoi tich ra suon bo ngarn, Tac dong c u a song gay di chuyeri
bun cat doc b o ve hai phia theo hai rnua gio dong bac va ta y nam dtm den
su thieu hut boi tich lon nhat d giiia bai theo mat cat doc va "dong boi tich
tong h o p di ve phia dong nam d u o i ta c dong u u the cua tr u o n g song dong
b a c . N a n g lu o n g p h a huy c u a song k h o n g lo n n h u n g ta c dong x o i 1 0 dang
ke do co su ket hop voi toc do dong trieu va dao dong muc nuoc trieu kha
Io n . S u dang cao m u c n u o c bien dong gap k h o a n g 17 - 32% g ia tr ] toc do
x o i 1 0 bC1 b a i. B a i van dang bien d a n g tiep tu c v a co h u o n g bien th a n h b a i
trieu cat va de bien tiep h;IC d trang thai xung yeu du dci duoc baa v~ bang
ke lat maio

• QPONMLKJIHGFEDCBA

TAl LIEU THAM KHAO

1. Nguyen Can va nnk, 1994.

Hoat dong dut gay hien dai vung Hai Phong - Quang Yen. Tai nguyen
va moi truong bien. Tap II. NXB Khoa hoc va k y thuat, Ha NOi.
2. CERC (Coastal Engineering Research Center), 1984.

Shore

protection

manual.

4th edition,

Washingtin

D. C.

3. Jelgersma, 1986.

A future sea level rise, It's impact on coastal
urhan development.
Vol. 1, ESCAP.

lowlands.

Geology

and

4. Nguyen Chu "oi, 'Iran D"c Th~nh va nnk, 1992.

Danh gia anh huong cua d~p Dinh VfI den vung cua Carn - Nam T r ie u
lien quan den sa bbi luong vao cang hai Phong. Luu tru tai phan vie n
Hai duong hoc tai Hai Phong.
5. 'Iran.D"c Thanh, Nguyen D"c cu, Nguyen Chu "oi va nnk, 1992.

Dieu tra khao sat muc do b o i tu de danh gia tinh kha thi cua viec x a y
dung hen ca Ngoc Hai, Luu tru tai Phan vien Hili duong hoc tai Hai Phong.
6. 'Iran D"c Thanh, Nguyen D"c C\1, Nguyen Chu Hili va nnk, 1993.

Moi truong

dja chat yen bo Hai Phong. Luu tru tai Phan vien Hai duong

hoc tai Hai Phong.
7. 'Iran D"c Tbc.anb,Nguyen Cbu "oi, 'Iran Dillb Lan, Nguyen "llu CiJ va nnk, 1995.

Do

Luan chung k h o a hoc k y thuat bao v~ tuyen de bai Duong 14 Son
- Hai Phong. Bao cao thuoc de tai KT.03.14 (Vie n Khoa hoc Thuy IQi
Ouoc gia chu tr i) ,
8- TNSVB

113


Tai nguyen va M oi QPONMLKJIHGFEDCBA
t r u i m g biln. T~p III - wvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC
1996

8.Nguyen Ngoc Thuy and Sui Dinh Khuoc, 1993.

El-Nino phenomenen
global warming and the 'sea level in the sea of
Vietnam and Bien fedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
D o n g sea. National seminar research and managemerrt
of Vietnam coastal zone. Hanoi, Proceeding of Vietnam IOC.
9. Vi~n Khoa hQCThliy l(,JiQu6c gia, 1984.

Nghien cuu bao v~ de bien Duong 14 Hai P h o n g . Baa cao luu tru tai
Vi~n Khoa hoc T h u y L<.1iQ u a e gia.
SUMMARY

STRUCTURE AND DEFORMATION OF THE ROAD N-O.14 BEACH
IN DOSON, HAIPHONG
Tran Due Thanh, Tran Dioh Lan, Nguyc:n Huu Cu,
Nguyen Chu Hoi, Nguyen Due Cu, Dinh Van Huy,
Nguyen Quang Thall, Pham Van Huan, Pham Van Vy,
Nguyen Thi Phuong Hoa, Nguyen Thi Kim Anh.

The structure of the Road N-O .14 beach consists sim ply of 2 layers. The
lower reaches 3m in thickness, com posed of fine - grained greenish grey
sands and the upper reaches 1m in thickness, fine - grained and yellow
sands. The interface between the two layer is in elevations from 0.5 to
1.5m /LSL
(lowest sea level). Based on characteristics of grain - size and
heavy m ineral com ponents of sedim ents, the beach can be divided into two
zones corresponding to tidal level intervals.
D uring the tim e 1981 - 1993, the beach was eroded in the part above the low
equatorial tidal level (1.10m /LSL) and it's surface was lowered at the rate of 2.5
- 3. O cm /yr. and deposited in the other part below this tidal level. According to
changes of the shoreline of which elevation is considered as the m ean tidal level
. (M TL), the beach was eroded at the rate of 4.1 - 7.5m /yr. The beach deform atin
was a result of com bination of causes such as hum an activities, tides, waves,
currents and the sea level rise. The m ost im portant cause was that the transversal
profile of the beach was shortened due to buiding up. the' sea dike in 1981. The
regular diurnal tide with the m axim um range of 4m m ade the beach deform ation
and' dispersed sedim ents from the beach in to the underwater slop. The total
longshore drift m oved Southeastward by the prevalence of NE direction waves
and the greatest discharge was transported ill the interval' between the low
equatorial tidal level and the m ean tidal leveL (1.10 - 1.86m /LSL). The sea level
rise at the rate of 2.24m m jyr. contributed a value from 17 - 31% to the erosion
rate of the beach. The beach can be changed into a tidal flat of sand in the

future and the sea dike will be continuously threatened to break .

. 114