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Nghiên cứu cơ sở khoa học và đề xuất các giải pháp khoa học công nghệ đảm bảo sự ổn định và độ bền của đê biển hiện có trong trường hợp sóng, triều cường tràn qua đê nghiên cứu, đánh giá hiện trạng các dạng kết cấu, điều kiện

(7)
BO
KHOA HQC
VA CONG
NGHE
CHUONG
TRINH
KHCN
CAP NHA
NIIOC
KC
08/06-10
B6
TAI:
"Nghien ciiu afsir khoa li(>c va de xuat cac giai phup
khoa
hoc cdng
nghf hdo diirn sir
on
djiili
va

dp
hen
ciia de
hien
Men
CO
trong
tririrng
hop sting,
trieu cif&ng
Iran qua de"
Ma
so:
KCOS.
15/06-10
BAO CAO
NGHIEN
CLfU,
DANH GIA HIEN TRANG
CAC DANG
K^T
CAU,
DI^U KIEN
THUY
LyC,
DAC
DieiVI OjA
KY THUAT
DI^N HJNH
CUA DE
BI^N
02 VUNG TRONG
DI^M
NGHIEN
CLfU,
LyA
CHON
DlfeU
KIEN
BIEN
CHO CAC MO
HJNH.
Cc quan chu
tri:
TrTOng
Dai hoc
Thuy Igi
Chu nhiem de
tai:
GS.TS. Ngo
Tri
Vieng
Ha
noi,
2010
BO
KHOA
HOC
VA CONG
NGHE
CHlTOfNG
TRINH KHCN
cAP NHA NU'dC
KC 08/06-10
B£TA|:
"Nghien
cuu cffs&khoa hgc
va de
xuat
cdc
gidiphap
khoa hoc cdng ngh$ bio dam
sir
on
dfnh
va
dp
ben ciia de Men
hien
c6
trong truing
hpp
song,
triiu cirdrng
tran qua
dS"
Ma
so:
KC08.15/06-10
BAO CAO
NGHIEN
CCrU,
DANH GIA
HI$N
TRANG CAC
DANG
K^T
CAU,
Dl£U
KIEN
THOY
Ug'C,
DAC
D|£M
DjA
KY THUAT
DI^N
HINH
COA
DE
B|£N
02
VONG
TRQNG
D|£M
NGHIEN
CLTU,
LLfA CHQN DI^U KI$N
BIEN CHO CAC MO
HINH
CHU NHElM
BE TAI
CO
QUAN CHU TRI
I)
GS.TS.Ng6 Tri
ViJng
BAN
CHU NHIEM
CHUONG TRINH
KC.08/06-IO
BO KflOA
HOC VA
CONG
NGHE
Hi
n6i,
2010
MUCLVC
MUG
LUC
1
BANG
CHU
GIAI
CAC
CHC
VIET
TAT,
K*
HI$U
3
DANH MUC CAC SO DO, HINH

5
DANH MUC CAC
BANG
BI£U
6
MODAU
7
I.
Mvcdich
7
II.
Phucmg
phap fluic hien
7
in.
Ciu
tnic
cua
bdo
do 7
CHUONG 1. PHAN TtCH,
DANH
GIA
CAC
DANG
K£T
CAU
Dfi
BIEN
DIEN
HINH CUA VUNG TRQNG DIEM NGHIEN
CUU
1
1.1. Khai quit
vi
hi
th6ng de
biln
Nam
Djiih,
Hi Tinh
1
1.2.
Phan tich ket
cau
bao
v?
de bien
3
1.2.1.
Kit
ciu
bao V? m4i dg
4
1.2.2.
Chan khay
b4o v6 mSi
phia bien
13
CHUONG 2.
PHAN
TICH,
DANH
GIA
CAC DAC
DEEM VE
DIEU KIEN
THUY
LVCTACDONGVAODE
VUNG TRONG DIEM
NGHIEN Cinj
17
2.1.
DJc diSm
ve
diSu
ki$n
thiy
l^c
tac dong vao de
vCmg
biin Nam Dinh
17
2.1.1.
Ch6 dp thuy tri6u 17
2.1.2.
Ch6 do song
gio
18
2.1.3.
Nu6c
dang
20
2.1.4.
ChS d$
dong chay
21
2.2.
DSc dilm vk diSu
kien thuy
Itfc
tac
ddng
vao
dS vimg biSn
Ha
Tihh
22
2.2.1.
Thuj'trieu
22
2.2.2. Chi
d0
s6ng gio
23
2.2.3.
Nude dSng
24
2.2.4. Dong chiy ven
bd
24
CHUONG 3.
PHAN
TiCH,
DANH
GIA
CAC
DAC
DIEM DJA KY THUAT
xAC
DONG
VAO
DE VUNG TRONG
DIEM NGHlfiN OOU
26
3.1.
M$t
s6 net ve vung
hot
vi
de bien Nam
Djnh vaHa TInh
26
3.1.1.
Bcrbilnvlid6bi&i Nam
Dinh
26
3.1.2.
Bo bien vide bien mUhh
27
3.2.
B4o
cao dia chat de bien Nam Dinh
vi
Ha
Tuih
28
3.2.l.Dia
chat de biin Nam
Djnh
28
. 3.2.2.
Dia chat d6 bien Ha TMi
30
3.3.
HiSn
trang va
nguyen
nhan hu hong
tCr
g6c dp dia
ky
thuat
33
1
3.3.
l.Higntr^ngvanguySn
nhan
hu
hong
de
bien
Nam
Dinh
33
3.3.2.
Hi?n
tr^g
va nguyen nhan hu hong
d6
biln
Ha
Tlhh
40
CHUONG
4.
CAC
VAN
DE
KHOA HOC
CONG
NGHE
TANG CUONG
ON
DJNHDE
43
4.1.
Cac
y^u
to
dnh
hudng den
6n
djnh cua de trong
viing
trpng
diem nghien
ciiu
43
4.2.
Anh hu6ng cua ket ciu d6
ikn sgr
6n djnh
cOa
de
44
4.3.
Mo hinh
toin
cho
dS
vimg
trpng
diem nghien
ciiu
45
4.3.1.
Cac
budc
tien
hMi
mo hinh hoa
bM
loan
45
4.3.2.
cac
phan mem thich
hpp
thudng
sir
d^ng
dl
mo
liinh
hoa bai
toan
tinh
de
45
4.3.3.
Mo hinh
toSn
bai toAn
dS
biln
Nam Djnh
46
4.3.4.
M6 hinh
toan
dS
biln
Ha
Tiiih
48
4.4.
Till
ngliiem
mo
liinh
vat
ly
cho de vung
trpng
dilm
nghien cuu
53
4.4.1.
cac
diSu
ki^n
bien tac
d$ng
vio
d6 trong vimg trong diem nghien
cihi
53

4.4.2.
Lap
phuong trinh
xac
dinh se-ry thi nghiem
58
K£T
LU^
VA
Kri;N
NGHJ
64
TAILIEUTHAMKHAO
67
BANG
CHC
GIAI
CAC
CHfj"
VI£T
TAT,
KY
Hlf
u
K^
hlf
u
H
W
b
m,
mi
mi,
m,
h,
K
K.
<P
y
Tgc
h„
K.
q
G
w

Yc
n
So
WT
w,
Wn
B
c
ai-2
n
G
7B
a
Don
vj
m
m
m
m
m
cm/s
g/cm3
g/cni3
m
cm/s
m3/s.m
T
%
g/cm^
g/cm^
%
%
%
kG/cm'
cm'/kG
%
T
Vm'
Dai
lirgng
Chieu cao de
Be
rpng
day
de
Bi
r§ng
dinh de
H$
so
mai
thupng
luu
d€
H^
so
mai
h^
luu
d6
H$
s6
mai
trong de
H^
s6 mai
ngoii
dS
Mytc
nu6c thupng luu
dS
Mvtc
nude
h^
luu de
H$
s6 tiiim cua dit dip de
G6c ma
sat
trong
cila
v^t
li$u
dip
Trpng
lupng
don vi
ciia
vat
lipu
dap
Trpng lupng
v^t
ligu
gia
c6
Clii6u
day
lop
dit nin
Hg
so tham cua nen
Luu lupng bo xung
tii
mai do mua
xai
trpng do phucmg tien giao thong
Dp im tu nhien
Dung trpng tu
nhiSn
Dung trpng kho
D$
rong
Hg
so rdng
Gidi han chay
Gidi han deo
Chi s6 deo
D$s$t
Lvtc dinh
kk
H$
so nen
liin
a
D$
rong
Trpng lupng
vi6n da
hojc
ciu
kifei
Trpng lupng rieng
ciia
ciu ki$n
Goc nghieng
ciia
mai
k6
so vdi
m^t
phing nim ngang,
HsD
KD
8D
Ls
Hs
8B
1
Hs
Ls
.
1,
Y>YB
Hs
?
<P
T
G,
Gi
a.
m.
mj
fl
ti
m
m
m
m
m
m
m
m
T/m'
m
m
T
T
T
cotga
=
m
Chi^u
cao song thiet
ke
H^
s6 on dinh,
tiliy theo
hinh dang
Ichoi phii
Chieu
d^y
ciia Idp dd lit mdi
Chi^u dhi
song
Chieu cao s6ng
Chi^u
day
t^
b^
be t6ng
H^s6:11
=
0,0075
d6iv6ib^Iatldian;
TI
= 0,10
d6i
v6i
b^
phmi tren
lit khan,
ph4n
dudi chit mach
Chi^u
cao s6ng
tinh
todn,
l^y
bang
Hsi%
ChiSu
d^i
song
Chi^u dii
c^nh
tim b6
t6ng
thuro phucmg
vuong goc vdi
dudng
m^p
nu6c
Trpng lupng rieng cua
nude
va be tong
Chi^u
cao s6ng thiet ke, lay
bJng Hsi/3
H?
s6 s6ng
v9
HS
so phu thuoc vao hinh
d^g
va
each
lap dat
cdu
kien,
ISy
theo
bing
Do
sdu truot
Trong
luong
khoi gia c6
Trpng
lupng
kh6i dat
trupt (thanh
phan
gay tnrpt)
Trpng lupng
khdi
dat trupt (thanh
phin
ch6ng trupt)
He so mai
d6c
cua de tren
mirc nude
HS
s6 mai
d6c ciia
mat
trugt
dual
m\rc
nude
HS
so ma sat
giOa Idp
gia
c6
vdi
dSt
tiian de
HS
s6
ma sat trong
giiia vSt
lieu gia c6 mai
DANH MVC
CAC
SO
DO,
HINH
VE
Hinh. 1-1.
Mai dS dupe bJo v$
bing
tr6ng
c6 4
Hinh. 1-2. Ket hpp giiia be tong
va
da
lat
khan 4
Hmh. 1-3. Bao ve mai bing ciu
ki?n b6
tong
ty
chen 4
Hinh. 1-4. Ciu
ki$n
be tong
da h$c
day 35cm 5
Hmh. 1-6. ciu kien be tong lien ket 02
chi^u
6
Hmh. 1-7. ciu
kiSn bS tfing mai
de hiin
Hii
Hau, Nam Dinh bi
an
mon 8
Hinh. 1-8.
6ng
buy chan khay bj mit
6n
dinh do ha thip bai 14
Hmh. 1-9.
H? th6ng
m6 han
thit nghi$m tji
Nam Dinh 15
Hinh.
3-1.
Lat cit
dja
chat
diln hhih d6
bien Nam Dinh 30
Hinh. 3-2. Lat cit dia chit
dik
hinh
dS
bien Ha Tinh 33
Hinh. 3-3. So
d6
minh
ho?
tuong
tac giOa
tai trpng ben ngoai va ben trong ke 36
Hinh. 3-4.
Cac cau
kien va
viSn da
bi bong x6 37
Hinh. 3-5. Co
chS
pha
ho^
tir phin ciu
kifn
hi
vo
hong 38
Hinh. 3-6. Co che pha hoai tir phin da lat khan bi bong
x6
39
Hinh. 3-7. Co che pha hoai tir phia trong
d^ng
39
Hinh. 3-8. Pha hoai do
m^ch
dim 41
Hmh. 3-9.
Pha hoai do hoa
16ng 42
Hinh. 3-10. Pha hoai do mit 6n
djjih mai
d6c 42
Hinh.
3-11.
Thim vao mai trong
dS
do
tran
dinh 43
Hinh.
4-1.
Giao dien phan mem CRESS 45
Hinh. 4-2. Mat cit
diin
hinh
dS
bien Nam Dinh 46
Hinh. 4-3. Tinh toan
6n
dinh
d6
Giao Thuy-Mat cat D13+10-Trudng hpp
tinh
thupng luu muc
nude
gia
cuong+sdng dang-Phuong
phap tinh Bishop 48
Hmh. 4-4.
MJtcitdi6nhmhd6biSnHaTTnh
49
Hinh. 4-5. Tinh
toan 6n
dinh de Lpc ha- 51
Hinh. 4-6. Trinh
ty
m6
phdng
bai toan
xac
djnh giai phap c6ng trinh
ciia Vi6n
Ciu
duong
va cong trinh thuy (Road and Hydraulic Engineering
Iiistitute)cua Ha
Lan 52
Hmh. 4-7. Lat cit dja chit
diln
hinh de bien Nam Djnh 56
Hmh. 4-8. Lat cit dia chit
diln hhih
de bien Ha
Tuih
58
DANH
MVC
CAC
BANG
BEEU
Bang.
l-I.
H$
s6 on dinh 9
Bang. 1-2. He
sfi phy thu$c vao
hinh
d^g
va
each
lip
d}t
ciu kien 10
Bang, 1-3. Trpng lupng
6n djuh
cua
viSn da
14
Bang. 2-1. So
lipu myc nude thyc
do trong thdi gian 22
nim tij
1970-1991
t?i
cac
tram cua
s6ng 17
Bang. 2-2.
Mvrc nude
cao nhit tinh vdi
cac
tin suit 18
Bang. 2-3.
Nude dSng 6
vimg
bd biln
Nam Djnh tai mpt so con bao dien hinh 21
Bing. 2-4. So lieu quan trie
tsii
tram Cira Nhupng 22
Bang. 3-1. Chi
tiSu
co ly trung
buih
idp 28
Bang. 3-2. T6ng hpp thanh phin
va
chi
ti6u
co ly
cac Idp
dit de bien Nam Dinh 29
Bang. 3-3. Chi tieu co ly chung cua idp dit dip 31
Bang. 3-4. Chi
tiSu
co ly chung cua
Idp
Idp
1
31
Bang. 3-5. Chi
ti§u
co ly chung cua
Idp
2 32
sang. 3-6. Chi
tiSu
co
1;^
chung
ciia
Idp 6 32
Bang. 3-7.
cac
th6ng so
cp
ban de Nam Djnh 35
Bang. 3-8.
Toe
dp
hgi
thip dia hinh bai bien d chan de do xoi
Id
35
Bang. 3-9.
Th6ng
ke
cac
doan de bi
v9 huygn
Hai Hau 37
Bang.
4-1.
T^ng
hpp thanh phin va chi
tiSu
co ly cac idp dit de biin Nam Dinh 46
Bang. 4-2. Chi tieu co ly chung cua Idp
1
49
Bang. 4-3. Chi tieu co
1^
chung ciia
Idp
2 49
Bang.
4-4.
Chi tieu
ca
I^
chung
ciia
idp 6 50
Bang. 4-5. Chi tieu co ly trung bmh idp 54
Bang. 4-6. Tong hpp thanh phin va chi tieu co
1^
cac idp dit de
biSn
Nam
Dinh
55
Bang. 4-7. Chi tiSu co ly chung cua
Idp
dit dip 56
Bang.
4-8.
Chi tieu co
1^
chung
ciia Idp 1
57
Bang. 4-9. Chi
tiSu
co ly chung cua
Idp
2 57
Bang. 4-10. Chi
tiSu
co ly chung cua idp
3
58
MdsAu
I.
Myc dich
Muc dich
ciia
npi dung nay la
t6ng
hpp
kk
qua phan tich,
danh
gia
hi$n
trang cac
dsmg
ket cau
d6
bien; dac
diim diiu ki$n
thuj'
lye,
dac diem dja ky thuat
diin
hmh tac
dong
vao
de biin cua 02 vimg trpng
diim
nghien
cihi;
lua
chpn kit ciu
dS
diin hmh va
dieu kien bien cho
cac
mo hinh toan va mo hinh
vjt
ly.
n.
Phinmg
phap
thyc hi^n
-
Tdng
hpp, ki thira
cac
kit qua
nghi8n cihi
tir trudc din nay trong
ITnh
vyc de biin.
- Phuong phap th6ng ke va phan tich
s5 li$u
thyc do.
- Phuong phap m6 hinh toan, mo hinh vat
1^.
- Phuong phap dieu tra thyc dja.
m.
Cau
triic
ciia
bao cao
Ngoai phin md diu, phin kit
lu^n,
phin
phy
luc,
danh muc tai
Heu
tham khao, npi
dung chinh ciia bao
cao
g6m
5
chuong
chlnh:
Chucmg 1 Phan tich, danh gia
cac d?ng
kit ciu de biin diin hinh cua vimg trpng
diim nghien
ciiu;
Chuong 2 Phan tich, danh gia
cac
dac diim vi dieu
ki6n thiiy
luc tac dong
vao
de
vimg trpng diem nghien
c^;
Chuong 3 Phan tich, danh gia
cac
dac diim diiu
kiSn biSn
dia ky thuat tac dong vao
de vimg trpng diem nghien
ciiu;
Chuong 4
cac
vin di khoa hpc c6ng nghe tang cudng
8n
dinh de
CmrONG
1.
PHAN
TiCH,
DANH
GIA cAC
DANG
K&T CAU BE
BI£N
BEEN
HlNH
CUA
VtfNG
TRQNG
DitM NGHlfeN CUU
l.I.
Khai quat vi
h|
thong de bien Nam Djnh,
Ha TTnh
De
biSn cac
tinh Nam Dinh
va
Ha
Tiiih
da
dupe
hinh thanh tir
lau,
hang
nSm dupe
boi tnic va nang cip din.
Nhi?m vy
chu yiu la
ngSn nude
biin di bao ve tinh
m?ng
va tai
san cua
ngudi
dan, bao
vS san
xuit. Chi
thih
trong v6ng 20
nSm
trd
Igi
day,
vi^c
nang cap
de biin
cac
tinh Bic Bp
dupe
chia lam 3 thdi ky: Thdi ky trudc du an PAM 5325 va
PAM4617, thdi ky sau dy
an
PAM 5325 va PAM 4617 va thdi ky sau bao
nam
2005.
Ngoai ra
cac
tuyin de bien
thih Ha
Tinh con
dupe cOmg
c6
nang
cip bdi
cac
dy an khac
nhu
OXFAM,
tuy nhien Do la
cac
m6c thdi gian danh diu sy thay
d6i Idn
vi quan niem
doi vdi de bien
Thin
kjr trirdc
dy in PAM 5325 vi PAM 4617
(tru-dc
1996): Hiu hit de
dupe
dip bing dit
t£ii
chS,
nghia
la noi
nao
co dit thit thi dip dat thit, con noi co dat pha cat thi
dip
bing.dit
pha cat, di
xdi
dudi tac dpng
ciia
s6ng.
BiSn
phap dip de chu yiu la thu
cdng
n8n
phin idn than de khong
dupe
dam
n^n
tot.
- Ve kit ciu
dS
bien: Dupe
bao
v$ bing nhieu hinh
thftc,
nhimg
noi phia trudc de co
rimg cay chin song
tdt
thi mai de chi
trdng
co; nhiSng noi trudc de khong co cay chin
song, mai phia biin thudng xuyen chiu tac dpng
ciia
song thi
dupe
bao ve bang ke lat da
khan, thong thudng la
lat
bing da
h^c
day 30cm tren
Idp
da dam day 10cm. Chan ke bing
lang
try
da
hoc hoac dai da hoc rpng
2T-3m
day 30cm tren
Idp
be dem chong
lun.
Do dudng kinh
va
trpng lupng vien da
lat nho
(d<30cm), ddng thdi kha nang lien
kit giiia cac vien
v$t
lieu kem nen vdi gio cip 7, cip 8 gap triiu cudng idp bao ve mai da
bi hu
hong,
bong
trdc
lam mit tac dung bao ve
gSy
sat id than
de.
0 nhimg
vimg biin tien
nhu
CS V$y
(Giao
ThuJ),
Van Ly, Hai Triiu (Hai Hau) Nam Dinh cac tuyin de ngoai
(Tuyen 1) thudng xuyen bi sat
Id,
phM cimg
c6 tuyin 2 di thay thi tuyin 1. Bmh
quancii
5
nam
dip mot tuyin mdi
iiii
vao phia trong di thay thi tuyin ngoai.
ThM
ky sau dy an PAM 5325 vi PAM 4617 (Sau nam 2000): Dupe sy tai fro
ciia
Chuong
trinh
luong thyc thi gidi (PAM) dy
an
phyc
hdi
va nang cip de biin cac tmh ven
biin Bic Bp tir Quang Ninh din Ninh Bmh dupe thyc hien tir
1996*2000.
Qua 4 nam
thyc
hiSn,
361.5km
dS
dupe nang cip vdi chi
tiSu
thiit ki la triiu cudng tuong
ilng
vdi
tin suit 5%,
gjp
gio
bSo
cip 9, trong do nang cip dyoc 87,5km ke chu yiu
tSp
trung
vao
cac
doan trpng diim vdi quy mo khac nhau phy
thuOc
vao miie dp anh hudng ciia song
gio.
Hiu hit
mai d8
biin cua Hai
H|u,
mot phin
ciia
Giao Thuy va
Nghla
Hung
thuSc
vimg biin tiin, bai trudc de biin
dii
manh thi kit ciu ke
bao v$
mai phia biin la chan
khay dupe chon bing hang
5ng
buy cao
1.5-i-2m
dudng kinh
Im,
dat sau din mat bai ty
nhiSn
trong
ch6a
diy da hpc. Phia ngoai dupe giiS bing lang thi da, tir dmh chan khay
dSn
cao trinh +3.0
*
+3.5
dupe
lat bing ciu
kipn
be tong day binh quan 0,25m tren idp
da
dam lot day 10cm va
vii
dia ky
thu|it.
Tit cao trinh +3,0m
hoje
+3,5m trd
len
din dmh de
dupe lat bang da lat khan trong khung da xay
hoic
be tong. Mpt so tuyin dinh ke co
tudng chin sdng bing
da
xay.
Trong 4
nSm
thyc
hi?n
dy an, do tac dpng cua vice ha thip bai trudc de, cac bai cay
bi xdi
Id
din ma yen ciu phai lam ke dai
hon
so vdi ban diu cua dy
an,
d Hai Hau (Nain
Dinh)
tdng
s6 de biin cd 33km, khi
x&y
dyng dy
an
pham vi phai lam ke chi 6km, din
cu6i dy
an
da phai b6 sung tdi 14km.
Dy in PAM 5325 vi PAM 4617
da
dat
dyyc
m^t
s6 kit qui ban dau nhu sau:
- Day la
lin
diu
tiSn dS
biin dupe thiit ki cd
h?
thing.
Cao
yiu ti tac dpng nhu
sdng, gio, thuy triiu, nude
dSng
dja hinh, dja chit, hai van, dpng lye hpc biin dupe di
cap di
tfah
toan
cic
thdng s6 co
ban
cua de.
- Day
la
dip cd diiu
ki^n
di
ap
dung
ciia
cdng
ngh$
mdi,
v^t
li^u
mdi vao de biin.
- Chi tieu thiet ke chpn vdi to hpp trieu cudng
gip
gio bao
cSp
9 co
nude dSng
la
phu hpp vdi diiu
ki$n
kinh ti
xS
h$i,
tiim nang kinh ti
ciia
dit nude
liic
biy gid.
-
Bap v$ mai
de bing ciu
ki^n
be tong due
sin
cd lien kit mang cd kha nang chiu
lye tit, phu hpp vdi diiu
ki?n
nin mai de, ding thdi phu hpp vdi diiu kien thi cong bing
thu cong.
Mot so van
Se
con ton tai:
- Phin
Idn
cac tuyin de diu
liy
cimg tieu chuin thiit ki va
cac
thong s6 tinh toan
nhu thuy triiu,
nude
dang, hudng va da gio,
- Thiiu tai lieu
co
ban phyc vu tinh toan va phuong phap tinh toan eon han che.
-
Mai
de phia biin
dupe
thiit ki bing m = 4+5
va mai
phia ddng m =
3
la qua doe,
so vdi
dS
biin
ciia cac
nude trong khu vyc va tren thi gidi.
- Bien phap dip
chii
yiu bing thu cdng
nSn
cdng tac dim nen bi han chi, dit dip
de phin
Idn la
dit cit pha khai
thae
tai chS c6 bpc
Idp
dit
thjt
day tir
0,5+1,0m
nhung
chit lupng dit bpc ciing con pha
cat,
co noi khong thyc hien
vi?c
bpc dit thit.
- Mat
dS va mai dS
phia ding khong
dupe
bio
v?
(ki ca
vi$c
tring co ciing ehua
tit),
nen khi sdng
tran
qua
hojc
mua
Idn gSy
xdi
lam
hu hdng de tir trong ra.
- Do
h^
chi vi kinh phi dupe tai trp nen
mai
ke chi lat cau
kiSn
d^n
cao trinh
+3,0ra hoac
+3,50m. De on djnh, cin thiit phii lat din dinh
dS.
- Thiiu thiit bi
va
ti chire do dac quan
trie
biin dpng ciia bai trudc de,
cac
yiu
td
hai van,
d0ng
lye hpc ven biin,
nSn
rit khd
khin
trong tmh
toan
va con hi dpng so vdi ki
hoach ban diu
cila
dy an.
Trong thdi gian dua vao sit dung din trudc 2005, nhm chung
cac
tuyin
dS
diu in
djnh. Mac diu
cac
tuyin de Ci
V|ly
(Giao
Thu^),
Hai Hau, Van
L^
(HM
Hau)
va NgMa
Phiic (Nghia
Hung) thupc tinh Nam Djnh lu6n
chju
tac
dOng
tryc tiip cua sdng
va
bai
trudc de ha thip
mjnh.
ThM
M
sau bao nim
200S;
Nam
2005 vimg biin Bic
B$
chiu anh hudng tryc tiip cua 3 con bao lien tiip: S6
2,
sfl
6 va s6 7 da lam
vd
tuyin de biin Cat Hai (Hai Phong),
m$t
so doan thupc de Giao
Thiiy, de Hai Hau va
d6
Nghia Hung (Nam Djnh), lam hu hdng
n^ng
nhiiu tuyin de
khac.
Ngay sau
bSo,
Thii
tudng Chinh
phii
da
ph6
duy$t Chuong trinh
bao
ve, cung c6
va
nang cap
cac
tuyin de biin
hien
cd tir Quang Ninh din
Quing
Nam, thyc
hien
trong giai
doan
2006-2010
tai quyit djnh si 58/2006/QD-TTg trong
dd
dat myc tieu trudc mit khic
phyc ngay
cac
do^
de hi vd, by hdng, tiin tdi
ning
cip ding
b$ toin
tuyen de biin dam
bao
ching
gid, bao cip 9 kit hpp triiu tin suit 5%, khu dan cu chong gid, bao cip 12 kit
hop triiu tin suit 5%.
Theo s6
li$u
thing
kS ciia cac
dja phuong, tinh din hit nim 2007,
hi6n
trang de
biin
Nam Djnh,
Hi
Tmh nhu sau:
* Tinh Nam Binh:
Cd 03 tuyin de biin vdi tong chiiu dai
la
90,82km
thuOc
dia
ban
03 huyen
la
Giao
Thuy,
HM H$u
va Nghia Hung. Trong nim 2006, 2007 ciing ci dupe 27,78km de xung
yeu theo tieu chuan trong QD58.
Hien tram
cdc
doan con
lai
chug dau tu
theo
OD58:
- Cao trinh: Chu yiu cd cao trinh tit +4,8m din +5,0m.
- Bi rpng mat: Ldn hon 5,0m: 5,63 km; nhd hon 5,0m: 57,409 km.
- Gia cd mat: Be tong: 4,76 km; cip
phii:
36,40 km; ehua gia ci: 21,88km
-
Mai
phia biin: da lat,
xty:
4,85 Km;
ehua
gia
cd:
58,19 km
* Tinh Hi Tinh:
Cd 12 tuyin de biin la vdi tong chiiu
Jii
la 147,90 km
thu$c
dia ban cac
huySn
Quynh Luu, Dien
ChSu,
Nghi
LOc.
Nam
2006,2007
da ciing ci dupe
13,03
km, 24km de
xung yiu theo tieu chuin trong QD58.
HiSn
tram
cdc doan
con
lai
chira
dau tu
theo
OB58:
- Mat de:
Chii
yiu cd cao trinh tit +3,50m din +4,50m,
m§t
sd doan cd cao
trmh
chi
tijt+2,0mdin+3,0m.
- Bi
r$ng
mit: Ldn hon 5,0m: 10,97 km; cong
l?i
mat de eon nhd.
- Gia ci mat: B6
tdng:
2,77 km;
ehua
gia
co:
217,99 km
-
Mai
phia biin:
da
lat,
xay:
51,85 km;
ehua gia
ci: 168,91 km
1.2.
Phan tfcb kit cau bao v|

biin
Dupe
dau tu qua nhiiu thdi
k^
vdi tiim
ning
kinh ti, trinh dp khoa hpc cdng
ngh$
d
cac mile
dp khac nhau.
H$
thing de biin Nam Djnh
va
Ha
TMi
c6
cac
dang kit ciu bao
ve kha da
d?ng,
t$p
trung vao
m$t
s6 dang sau:
3
1.2.2. Ket cau bao
vf
mdi di
1.2.1.1.
Hi£n
trang
Trudc day, hiu hit mil
dS
chi
bao v$
bing trong cd, chi si it nhimg doan true dien
biin dupe bao
v$
bing
da lat
khan, da
xay khii hoic
kit hpp giiia lat ciu kien be tdng ty
chen
va
da
lat
khan
^ype ap
dyng tir thdi
kj-
dy
an
PAM).
Trong nhiing
nam
gin
day,
qua thyc ti
ciia cie
con
bSo nam
2005, 2006,
dSe
biet
la
sau khi cd quyit djnh si 58/2006/QD-TTg ciia Thu tudng Chinh
phii,
da lat khan vi da
xay
khdi hiu nhu
khdng
cdn
dupe sii
dyng trong viic
bao vf
mix de biin. Chi chip
nhan
k6t
cau mai
de bing cau kien
bS
tdng
diic
sin ty
ch6n
thanh mang mim.
Hinh.
1-3.
Bao ve mai
bang
cau kien be tong tu
chen
Hinh
thirc
vi
chilu
diy
viln
ciu
kl?n
lit mai
cflng
co nhiiu dang khic nhau,
tap trung
d m$t vii
dang sau:
-
Dgng
cau
ki^n
bS tong da hpc day 35cm:
Dupe
ap dyng d cong trinh ke Hai
Thinh 2 tren tuyen dS
biin
Hdi
Hau,
Nam Dinh
tir nam
1991. Qua con bao nam 2005,
cong trinh vin 6n dinh.
Hinh.
1-4.
Cau
kien be tong
dd
hoc day 35cm
- Dang cau kien be tong Tscl78 day 23cm:
Dupe
ap dung d cong trinh ke Doanh
Chau - Ba Non tren tuyen de bien Hai
Hau,
Nam Dinh tir nam 1994. Day la cong trinh
thir nghiem, cua Vu Phong
chdng IG lut
va
QuanJy
dS diSu (hiSn la
Cue
Quan ly de
diSu
va Phong
chdng
lut
bao).
Qua con bao nam
2005,
cong trinh
van
on dinh.
Hinh.
1-5. Cau kien be tong
Tscl 78
lien ket 3 chieu
- Dang cau kien be tong ngam 01 hoac 02 chieu:
Dupe
ap dung d kha nhieu cong
trinh ca d Nam Dinh va Ha TTnh. Qua can bao nam 2005, hau het cac cau kien dang nay
deu on dinh.
Hinh.
1-6.
Cau ki^n
be
tong lien
kit 02
chieu
1.2.1.2. Bank gia cac dang ket cau bao v6 mai
a) Qua
thuc
ti: Qua thyc ti eon bao s6 7 nim 2005
la
tran bao ldn, do bp vao dit
lien trimg thdi diim myc
nude
triiu cao da lam vo, hu hdng nhiiu doan de biin. Tap
trung vao
cac nguySn
nhan sau:
- Ket
cau
ke
bao vp
mil de phia biin nhiing doan tryc tiip chju tac dpng cua sdng
eon ehua du kien ci, ding
b$
di ching gid bao cip
11,
cipl2: Hiu hit
cie
doan de bi
pha hdng
la
tryc
di$n
vdi biin chju
tac
dpng tryc tiip cua sdng ldn. Thyc ti qua
cie trin
bao nam 2005 cho thiy, nhiing
do?n dS
tryc tiip biin, mai phia biin dupe bao ve bing
da
hoc lat khan, da
xiy
tir cao trinh +3,50 trd
ISn
(tit cao trinh +3,50 trd xuing bao
vS
bang
cau
kien be tdng do trudc
day
khdng dd kinh phi diu tu) la khdng dam bao in djnh
ben viing; bao si 7
nam
2005 song ldn da lam hu hdng
ning,
hoac phi buy phin da
lat
khan, da xay tir cao trinh +3,50 trd len, dan din vd de biin nhu: de biin I - Dd Son, de
bien Cat Hai, de biin Nam Dinh. (nhiing doan mil de phia biin
dupe
bao
vf
toan

bing
cac loai cau Icien
be tdng due sin cd dd chiiu day, trpng lupng
phii
hpp thi khong bj phi
hoai trong bao).
- Tudng
ciiin
sdng ehua du kien
co:
Tudng chan sdng tren dmh de
bang'da
xay hoac
be tdng thudng (khdng cd cit
th^p),
mdng
tudng
dupe
dat ehua du
sSu
nen
khSng
dam bao
dn dinh, ben
canh
do hinh
dgng
tudng
m^t
sd khu vyc
chira
thyc sy phu hpp, khi chiu tac
dpng
true
tiip
ciia
sdng, tudng bi
lat,
hoac
bi be gay din den vd
de.
Day
la
co che vd de da
xiy ra
d Dd
Son
-
Hai Phong.
- Sdng va sdng
leo
cao hon
miic
sdng tinh toan khi thiet ke trudc day: Giai doan
trudc day de dupe thiit ki ching vdi gid bao cap 9, trieu tin
simt
5%, trong khi bao sd 7
nam 2005 vdi
siie
gid cip 12,
giit
tren
cap
12,
l?i
trimg vdi thai ky
tridu
cudng
gay
sdng
ldn
virpt miic
thiit ki cia
d6.
Sdng
tran
qua mit de, gay
s?t
id mai de phia ding, mat de
(nhiing doan mit
dS
ehua dupe ciing boa, mil dd phia ding ehua dupe
bao vS
bing da
lat,
hoac trdng cd)
giy
vd de tit phia trong ra,
Cac hu hdng
Idp bao vi
mai bing ciu ki$n
bS
tdng
diic sin
cd hen kit ciing cd xiy
ra nhung
la
nhiing hu hdng
eye
bO.
Nguyen
nhin
chu yiu la do than dd bi ldn qua
mde
cho phep,
Idp
lpc giiia
thSn d8 va
idp bao ve khdng tit tao
nSn
hi$n tuong xdi ngim
lam
ring than de,
gay sip
mai
hojc bS
tdng
diic
ciu kien khdng dii cudng dd hi sdng, va
dap lam an mdn theo thdi gian. Dudi diy
la
mdt si hmh anh hu hdng
eye
bp mai
dS.
Hinh.
1-7. Cau
ki?n
be
tong
mdi de
bien
Hdi
Hdu,
Nam Dinh
bi an
mon
b)
Ve
mat ly
thi^St:
Trong luong yeu cau cua
khoi
phu
mdi:
Trgng luong toi thieu
eiia
vien da hoac
cau kien lat mai
dupe
xac dinh theo cong
thCtc
Hudson:
'^"M
cot gar
(1-1)
Trong dd:
G:
Trpng lupng vien da hoac cau kien (tan = T).
YB
: Trpng lupng ri^g ciia
cau
kien
(T/m^)
y :
Trpng lupng rieng ciia nude
(T/m^)
a:
Goc
nghidng
cua mai ke so vdi mat phing nim ngang, cotga = m.
HSD:
Chiiu cao sdng thiit ki (m).
KD
; He si in djnh,
tiiy
theo hmh
d?ng
khii phii va liy theo bang sau:
Lo^i
khoi
phQ
Da
hpc
Da
hoc
Tam
be tdng
diic
sin
Tam be tdng
diic
sin
Bang.
1-1.
H4
so on dfnh
each
xip
Di roi hai idp
Lat
khan
Qh&p dOc
l^p
Ty chen thanh
ming
KD
3
4
3,5
5 + 6(*)
(*) Cdn
kiem
tra gid tri
th{cc
te doi vdi
titng logi
mdng.
Chiiu
day
yeu cau cua
khoi
phu mdi:
+ Ldp phii mai bing da hpc lat khan: Khi 1,5
£
m < 5 thi
d$
day in dinh tmh theo
cdng thiic:
So
=0.266-
H,
(1-2)
YB-r4tniHs
Trong do:
5D:
Chiiu diy
eda
idp da lat mai (m)
YB
: Trpng lupng rieng cua
da (T/m^)
Y
: Trpng lupng rieng
ciia nude (T/m^)
m
:
He si mai ddc ke
Ls
: Chiiu dai sdng (m)
Hs
: Chiiu cao sdng (m).
+ Ldp phii mai bing tim
ban
be tdng:
rinh
theo cong thuc
trong quyphgm
thiit ki de cua
Trung
QuSc:
Trong dd:
SB:
Chiiu day tim
ban
be tong (m);
(1-3)
r|:

si
t)
=
0,0075
dii vdi ban lat khan;
T|
= 0,10 ddi vdi ban phin
trdn lat
khan, phin dudi chit
mach;
Hs:
Chiiu cao sdng tinh toan
(m),
liy bing
Hsi%;
Ls:
Chieu
dai
song (m);
It:
Chi^u
dai canh tim bS tong thuo
phuong
vuong goc vdi dudng
mep
nude
(m);
m:
H^
s6
mai
doc;
•y,
YB:
Trpng lupng rieng cua
nude
va be tong
(T/m^).
Tinh theo cong thuc
Pilarczyk,
K.
W:
s ^
9
r,-r
Trong dd:
Hs:
Chiiu cao sdng thiit ki (m), liy bing
Hsio;
^: He
si sdng v6 tinh theo cdng
thire:
(gg
(1-4)
f
= -
(1-5)
(p:
He
s6
phu
thu^c vio
hinh dang va
each
lap dat
cdu
kiSn, lay theo bang:
Bang.
1-2.
H$ so
phu
thuQC
vao hinh dang vd cdch lap dat
cau
kien
Loai va
c&ch
lap
d^t
cau
ki^n
Tam lat dat nam
Tam
lat
dat tren ldp Geotextile va nSn
dSt
set tot
Tam lat tu chen
Tam
lat
tu chen tren ldp
d$m t6t
9
4-=-4,5
5
6
8
-
Tiqh
toan in dinh cdng trinh gia cd
mai
de:
+ Tinh toan on djnh ting thi, gim:
On dinh trupt cua cdng trinh gia ci bd cimg vdi
thSn
d8;
On dinh trupt theo
mjt day
cdng trinh gia c6 bd
(On
dinh
tru0 ciia
cong trinh gia co ha cung vdi than de
theo phiJt lyic
G; 6n dinh
tru0
theo
mgt
day cong
trinh
gia co
her co
the dan gian hod
thanh
truat
tdng thi
theo mgtphang
gay khuc)
Cdng
thdc
tinh

si in dinh
ciia
khii trupt:
Gj-sinoTj + Gj-cosoTaJgaj +Pj.sin(a2 +a^)ig<p
"
i',.cos(a,
+«3) (1-6)
10
Pj =Gj.sinaj
-Gj.cosa^Jgip-
Ct
-Pi.cos(a|-a2)
(1-7)
(1-8)
sinOTi
i^i
~ GpSinflTi
-/,.cosar,
Trong dd:
fl:

si ma sat giiia
cac
ldp gia ci vi than de;
<p:
Gde ma sit ciia dit nin;
C:
Lye
dinh ciia dit nin;
T:
DO sau
trupt;
Gi:
Trpng lupng khii gia ci;
G2:
Trpng lupng khii dit trupt (thinh phin
gSy
trupt);
G3:
Trpng lupng khii dit trupt (thinh phin ching trupt).
+ Tinh toan in dinh
nil b$ Idp
gia ci: Khii gia ci vi than de la
vat li$u
cd cudng
d0
ching cat khac nhau, khi myc nude thip thudng
xay
ra trupt theo
mat
tiip
xdc
cd
cudng dp chong cat
yeu.
Phuong trinh on djnh
(1-10)

(1-11)
(1-12)
Trong do:
mi:
He s6 mdi d6c
ciia dS
trSn
m\rc
nude;
m2:
HS s6 mai
d6c ciia
mat truot dudi muc
nude;
n: n =
fi/f2;
fj:
He
s6
ma
sdt gifia
ldp gia
c6
vdi dit than de;
f2'-
H# s6
ma sat trong
gitla
v^t
li^u
gia c6
mai;
k
-
-^
(p:
Goc ma sit
ciia
khdi gia c6 mdi;
fl
fj-
Tri
s6 hS
s6 ma sat xac djnh qua phuong trinh
-I-
Tinh
6n
dinh ldp gia c6 bd khi c6
sii
dyng vai
loc
dia ky thuat (geotextile):
G,
< / Gj
hoac
^ = tga<
F^
Gj
Thuc te dp
diing
- Chpn he s6 mdi: Thudng
idy
theo
h$
s6
mdi
de
hi^n
cd hoac cac doan tuong tu da
lam,
h$
s6 mai m =
3 -^
4.
Ddi vdi
nhOng
mdi de
hi?n
da cd ldp bio
v§,
Bp da cd
vSn ban
chi dao khi ciing
CO,
nang cap
khong dupe b6e ldp gia c6 cu,
dio phd
de de han
chi
rui ro, dam
bdo
an
toan dS khi cd gid, bao trong qua trinh thi
cSng
va
dam bdo
tinh xa
h^i.
- Chpn ldp gia co bao
vS
mai:
Qua
th\rc
t^
tir
bao s6 2, sd 7
nam
2005 ed
thS
khang
dinh cac
cau
kien be tdng
bao
v^
mai
ngoii
da lam trudc day la on djnh, da lat khan va da
xay
khdng dn dinh. Vi
v$y,
toan bp
cac hh
so thiit
kl
ciing
c6,
nang
cip de biSn
dSu
chpn
ldp gia cd bao ve mai phia
biin bang
ciu
ki^n bS
tdng
due sin
dang
tg
chen. Da lat khan
chi
sur
dung ddi vdi dS
ciia
s6ng, da xay hiu nhu khdng dupe sd dyng do tuoi thp khong
cao,
thi cdng
phiic
tap va khd giam sat chit lupng cdng trinh.
- Chua tinh dSn phuong an
vira
bao
v?
mdi
trvre
tiep,
vira
trdng
cay
chin song va
xay dung cdng trinh
gidm
song,
glG
bai.
- Tinh ldp gia co bao ve mai:
Tinh
toan dd theo 03 cong
thiic
da neu trong Tieu
chuan. Tuy nhien khi tinh chiSu day ldp phu theo cdng thiic
ciia
quy
pham
Trung Quoc
va cdng thiic Pilarczyk,
K.W
cd
sir chenh Ifeh
ldn. Nguyen nhan do ket qua
tinh
chieu
cao sdng
Hsi%
va
Hsi/3
va
Ls
khong chuin.
- Tinh on dinh mai:
Hau
hSt cac Tu vin bd qua tinh on dinh
nSi
bd ldp gia c6, chi
tinh dn djnh trupt
t6ng
thi.
Kit
qua tinh
todn h$
s6
hn
dinh trupt t6ng
thi
thudng ldn hon
1,2[K].
- Ldp dem: Trong thdi gian
gan
day, vdi lpc dja ky
thulit dupe
dung phd biSn rdng
khip,
hiu nhu khdng
sCr
dyng ldp lpc
truyln
th6ng.
*
NhSn
xet
- Mai
dS
phia
biin
cd hS sd mdi m
^
3, dit dip than
dS
co gdc ma sdt trong tuong
ddi ldn nen
kit
qud tinh todn
6n
dinh trupt t6ng
thi
va
6n
dinh ndi bp ldp gia c6 diu vupt
ySu ciu. Tuy nhien, viSc chpn hS sd mdi
dS
bien con quyit dinh
din
chieu cao de va quy
md ldp
gia
cd
bdo
ve mdi (qua cdc cong thuc tinh co the nhan xet chiiu cao song
leo
vd
trgng
lugmg.
chiiu day lap phu mdi ty
le nghjch
vdi
h?
so mdi). Vi
v$y
khi chpn hS sd
mdi de phia
biin
cin dua ra nhiiu phucmg dn
dl
l\ra
chpn phuong an t6i
im.
12
-
Hifn
stir dyng
nhiSu lo^i
ciu
ki$n
be tong dl bao ve mdi de biSn trong do hdu
hfet
khong
CO
trong Tieu chuin thiit kS nhung khi tinh toan chiSu day, trpng lupng lai su dung
cac cdng
thdc
vd
h?
s6 thyc
nghiem nSu
trong
TiSu
chuin.
Doi vdi cau
ki^n
be tdng dung bdo
v?
mdi de
biin,
vdn dS
quan trpng
Id
chieu day,
trpng lupng cua ciu
ki?n
va mac bS tdng, khdng phu
thu^c
nhiSu vao hinh dang. Do vay
nen chpn mpt sd
lo^i cdu
kiSn don gian, dl thi cdng, cd
thi
dp dung thi cdng
ea
gidi de
dua vao Tieu chuin, xdc djnh cdc
h?
sd thuc nghiem, tiSn tdi chuan hoa tao
thudn Ipi
cho
ccdng tac qudn
l^,
xdy
dyng.
- cin dua ySu ciu
kilm
tra dp on djnh
ciia kit
ciu mdi de
biin
trong trudng hpp
bao vupt thiit
kl
(da tiing xdy ra tai khu vyc).
1.2.2. Chan khay
bdo vf mdi
phia biin
Tieu chuan thiit kS quy dinh cin
b6
tri
chdn
khay d vi tri ndi tiSp
chdn
de
va
bai
biin.
Loai hinh va kich thudc chan khay xdc dinh theo tinh hinh
xam
thuc bai
biin,
chieu
cao sdng (Hs) va chiSu day ldp
phii
mai. Cd hai loai chan khay la chan khay nong va
chdn khay
sau:
- Chan khay ndng: Ap dung cho viing cd
miic d6 xdm
thyc it, chan khay chi chdng
do dong chdy do sdng tao ra d chdn de, chan khay kSt
cau
bang dd
hSc
xIp,
cd cdc hinh
thdc:
D^g
thSm phu cao;
Dang
thIm
chdn trong dit;
Dang md nhd.
- Chdn khay
sdu:
ap dyng cho vung bai bien bi
xam
thuc manh. Chan khay
sau
cim xudng khdng nhd hon 1,0m. Thudng
dimg
cdc loai:
Chan khay bing cpc go;
Chan khay bing cpc BTCT
hodc
hang ong be tdng.
1.2.2.1. Hien trang chdn khav de
biin
Nam Dinh va Ha TTnh
Hi$n
de
biin
Nam Dinh, Ha
Hhh siir
dyng nhieu dang chan khay khac nhau tuy
thupc
diiu ki§n
tu nhiSn
\^\
tiing khu vuc. Trong do chu
yiu
dp dung hai
Wnh
thirc chan
khay sau:
- Chdn khay nong
kit
ciu dd hdc xSp
dgng
hinh thang ngupc:
Dupe
dp dung phd
biin
d
nhOng
khu vyc it chiu tac ddng cua sdng nhu viing
ciia
sdng,
viing
cd cay chdn
song phat trien
t6t,
viing
biin
boi,
13
- Chan khay
sau
dang ong buy
diic sin
bing
b&
tong ed chiiu cao khoang 2,0m
chdn,sau
xuong mit bai,
ap
dyng d
nhthig
khu vyc biin tiin, bai khdng on dinh bii xdi
theo mua,
1.2.2.2.
Banh
gia on dinh
chSn
khay
a) Qua thuc ti
Qua
si
iidu quan
\j,
theo ddi thyc ti,
cac
hinh thirc
chSn
khay de bien d da ap dung
d Nam Dinh vi Hi Tmh la
phii
hpp, gdp phin on dinh he thong de biin trudc cac tac
dpng cua thien tai,
dac biSt
la hinh
thite
chan khay sau
ip
dung d de biin Nam Dinh da
tdn
t?i
trong thdi gian dii
U^e
hien tupng xdi mdn
h?
thip bai. Din nay tai nhieu khu
vyc ong buy chan khay da bj nil len khdi
mjt
bai, nhiiu cho nhd len khdi mit bai tdi
0,50m, nguy co sap di rit cao.
Hinh.
IS. Ong
buy chdn
khay bi mdt 6n dinh do ha
thdp
bai
b)
vi
mat ly thuyit: Khi thiit ki chan khay de biin, Tieu chuin thiit ki da hudng
din chi tiet
vipc
on dinh
vidn vit liSu va
kha nang xdi
sau
tai
vj
tri chin khay.
- Tinh toan kich thudc da
lim
chin khay:
Ydu
ciu: in dinh dudi tac dyng ciia dong chiy do sdng tao ra d chin de.
Trpng lupng in dinh ciia vien da
dirpc xac
djnh theo gia tri vin tic
eye dji
cua
dong chay do sdng tao ra d chan de, cho
sin
trong bang tra:
Bang. 1-3.
TrQng lugng
Sn djnh cua vien dd
VMax(in/s)
Gd(kg)
2,0
40
3,0
80
4,0
140
5,0
200
- Tinh
toan
chiiu sau bd tri
chSn
khay: Thudng chpn
Hrfi =
0,78Hsi
Ket
luan:
- Dieu kien de xdc dinh loai hinh va kich thudc chan khay trong Tieu chuin thiit kl
cdn qua chung chung. Cin dua tieu chi dl xdc dinh ro
miic
d^
xdm
thyc bai it va
miic
do
xam
thyc bai nhiiu.
- Mdi hudng dan tinh trpng lupng viSn da tai chdn de, tuy nhiSn thuc
tl
kh6 co the
tim
dupe
dd cd kich thudc va trpng lupng theo yeu ciu.
- Mdi chi c6 quy dinh chan khay sau phdi chdn
xuIng
khdng it hon 1,0m, chua co
hudng din tinh todn chilu sau chdn khay cin thiit.
Vi?c
dp dung chan khay
sau
d6i vdi
nhOng
khu vuc
biin
tiin,
bai
biin
thudng
xuyen bi ha thip chi cd tac dung trong mdt thdi gian nhit djnh. Khi bai bj ha thip
din
gidi han nao do, chan khay se
bi
mit In dinh keo theo cac sy co
vl
de. De tao In dinh lau
dai cho cdc tuySn de bien, can tdng cudng
kit
hpp cdc biSn phdp bdo
v?
bai,
tao
bai,
trlng
cdy
chan sdng tai cac vung
biin
hi xam thyc, nhiing khu vuc trudc
dS
chua co bai hoac
bai thdp, Vdi viing bai khong co
phii
sa, khdng trdng
dupe
cdy thi phai co cac cdng
trinh gidm sdng
fliich
hpp nhu ke ngim, md han
ho^c
nudi bai bang tau
hiit
cat.
Qua thuc tl bao sd 7 ndm 2005 cho thiy
rimg
cay chdn sdng phia
biin
dong vai tro
bao '/S
de
biin hit siic
quan trpng nhd cd
cay
chan sdng, cho nen de Binh Minh (Ninh
Binh) toan bd de Thai Binh va nhieu doan
ciia
de Nam Djnh ngay tai de Hdi Hau do cd
thi
khang dinh cd doan chua
dupe
lam ke kien cd nhung cd bai cd
cay
van dn dinh.
HiSn dpc bd biSn Nam Dinh, d khu vyc bien tien manh da
dupe
thi diem xay dung
hS
Ihdng
md han
gdy
bdi tao bdi, da dua vao
sit
dung
dupe
vai nam. Qua sd
liSu
theo doi
cac
cdng
trinh
ve eo ban dn dinh, phdt buy cao hiSu qud gdy bdi tao bdi da de ra.
Hinh.
1-9.
He thong mo han thu
nghiem tai Nam
Dinh
Thuc tl cho thiy cdc md han da xdy dung thi
diim
tut trudc den nay cdn mdt so ton
tai sau:
15
+ Phan ldn cdc md han cd kich thudc ngdn so vdi yeu ciu
+ Khoang
each gifta
cdc md hdn chua hpp ly.
+ Ldp bdo ve
(nhdt
la phia dau md hdn) chua
dupe
tinh todn
dii dh
ddm bdo In
dinh khi chiu tac ddng cua sdng.
+ Md han
bing
dng vdi dja
kj^
thu$t
kem on dinh do cong
ngh^
lien
kit
va bien
phap thi cdng chua phu hpp.
-I-
Nudi bai la
biSn
phdp
tit,
vira
rS
tiin vira
phu hpp vdi moi trudng sinh thai dang
dupe dp dung nhiSu tren the gidi.
6 nude
ta
vi^c
dp dyng cdn kho
khdn
do thiiu trang
thiit hi.
Tuy nhien nhu da phdn tich d tren, cong trinh giu: bai, gidm song d
nhOng nai
khdng trdng dupe cay chdn s6ng
Id hit siic
cin thiSt, cin dupe
tiip
tuc nghien cuu dl co
bien phdp phu hpp,
nhdm
phdt buy hiSu qud
ciia
cdng trinh, ddng thdi cin thi diem dp
dung cdc
bi$n
phap khac nhu nudi bai, ke ngim ddm bdo 6n dinh lau dai, dap
ling
ngay
cang cao,,yeu cau phdt
triln
kinh tl - xa
h0i
ven bien, dac biet la ben bien
bde
Bo.
Mdt trong
nhfing
quan
diim
cin dupe nhit quan khi xdy dyng du an la xac dinh
tieu chuan thiSt
kS dS
bien phdi tren eo sd va tam quan trpng cua khu vyc dupe de bao ve,
tir tir
cdc yeu td tac dpng cua
timg
vung, tung tuySn ma cd
thi
cd tieu chuin cho timg
vung,
tCmg
tuyen khac nhau.
Mudn
vdy,
cong tac dieu tra co ban phdi
dupe
quan tam dung muc, nhdt la diSu tra
cdc thdng sd ve thuy trieu, sdng, gid, dong ven,
diin biin
bd, bai va tinh hinh kinh te - xa
hdi de phyc vy cho vice hoach dinh qui md va
mijrc
dp nang cap he th6ng de bien phu
hpp.
Cd
thi
khdng
dinh
de bien noi chung va dS
Bac
Bd ndi rieng,
nlu
trude de co bai
dn dinh, cd ddi cdy chan sdng trude de rdng
tir
100m trd
ISn
thi vdi gio bao nhu vira qua
theo nhu tiSu chuan thiet ke cua dy an PAM 5325 de
van dam bao 6n
dinh. Vi vay co
thi
ket luan: DS on dinh de bien thi viSc
bao
TS
bai va trdng cay chan sdng la quan trpng hon
cd. cin
dupe
uu tien
ddu
tu. NSu chi
tip
trung dl
ddu
tu de ma khong quan tam
din
viec
giiJ
bai thi cdng tdc bao ve an toan de
biin ludn ludn
hi dpng. Doi vdi de, cin co bien
phdp bao vS mdi phia
ding
thich hpp de chdng xoi mon do
nude
mua va do song tran qua
dS.
16

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