DOI SANH KET QUA PHUONG PHAP MA TRAN DINH Ll/ONGVA PHUONG PHAP QUYTRINH HE
THONG CAP BAC AHP
ABSTRACT
At present on the world, there are many methods to evaluate, forecast and do zoning of landslide procedures on taluys and slopes, there are also a lots of researchers and scientists who pay attention to the quantitative ma- trix method (or multi-variate analysis
method) and AHP hierarchy system procedures method.
This article mentions the comparison between the results of quantitative matrix method and the AHPA hierar- chy system procedure method, so that to suggest the selection of the optimal application method.
Th.S Nguyen Dure Ly Pho giam doc Sd Khoa hoc va Cong nghe tinh Quang Binh 17A - Quang Trung - TP. Dong Hcii - tinh Quang Binh Dl dong: 0913.295.246 GS. TSKH Nguyen Thanh 11A-Phan Boi Chau-TP Hue Dien thoai: 054.3822410
H
ien nay, tren the gidi cd rat nhieu phuong phap 6iiac sd dung de danh gia, d u b a o , phan vCing qua trinh trupt Id dat da tren sUdn doe, mai ddc; ed nhieu tac gia, nha nghien edu quan tam den phupng phap ma tran djnh lupng (hay phUPng phap phan tich da ehi tieu) va phuong phap quy trinh he thdng cap bae AHP.Bai bao nay de cap den viee ddi sanh ket qua phuong phap ma tran djnh lupng va phupng phap quy trinh he thdng cap bae AHP, tren cP sd dd de xuat lUa chpn phuong phap dng dung tdi Uu.
1. Oat van de
Qua trinh trdpt Id dat da tren sddn doe, mai ddc dddng giao thdng mien nui (gpi tat la QTTLDO), trong qua trinh phat sinh va phat trien deu bi chi phdi bdi hang loat eac nguyen nhan va dieu kien cd ngudn gdc t d nhien hoac nhan sinh cung tdn tai, van dpng va tac ddng tddng hd lan nhau trong Dja he tU nhien - ky thuat phde tap dien ra trong khdng gian va theo thdi gian nhat djnh. Vi vay, viee danh gia, d u bao, phan vung chinh xac QTTLBO tren sUdn ddc, mai ddc la van de khdng ddn gian.
Nham de xuat eac giai phap phdng chdng, xd ly dam bao tinh khoa hpc, thuc tien va cd hieu qua thi trude het can so sanh, lua chpn phuong phap phu hpp va tuong ddi tdi Uu de danh gia, d u bao, phan viing qua trinh trUpt Id dat da tren sddn ddc, mai doc.
2. Phuorng phap ma tran djnh iifcfng danh gia ciTdng do tac dong tucng ho cac yeu td anh hudng den qua trinh trUqrt Icr dat da tren sildn ddc, mai doc mien nui
Theo phdong phap ma tran dinh lupng, eudng dp tac ddng tdPng hd K cua eac yeu td anh hudng thude eac quyen khac nhau den QTTLDO the hien d bieu thdc dudi day:
Nguyen DiifcLy NguyinThanh
K = 100% M
M = Z I. A . = I A i + l2A,2 + IjA,,-^.... + l„A,„
Mma«=ZliAj„,„
^ ^ l , * A , +l^*A„+...-H„''Aj, ( l , + l 2 + l 3 + - - U * A j _ Trong do:
n - Tong sd yeu t d tac ddng (nguyen nhan, dieu kien) dUa vao danh gia;
i -Yeu t d t h d i ;
I, - He sd tam quan trpng eua yeu td t h d i ;
A - He sd cap dp tac ddng eua yeu td t h d i .
M -Tdng dai sd tac dpng tdong ho eua eac yeu t d (i) dUa vao danh gia d cap dp tac ddng a. hien tai eua QTDBLCT.
'^max" Tong dai sd tac ddng tddng ho Idn nhat cua cac yeu td (i) dda vao danh gia d cap dp tac ddng Idn nhat aji max eCia QTDDLCT.
K = Cddng dp tac ddng tdng hpp tUPng ho eua tat ea cae yeu t d (i) dUa vao danh gia (%)
Phuong phap ma tran djnh lupng danh gia cUdng dp tac ddng tUdng ho cae yeu t d anh hudng den QTTLDO 6iJac tien hanh theo eac trinh tU sau:
Thd nhat, can xac dinh danh mue eac yeu t d anh hudng quan trpng can dda vao ma tran danh gia;
Thd hai, thue hien phan tich, danh gia va lua chpn he sd tam quan trpng 1, eua tdng yeu t d (i);
Thd ba, xac djnh cap d d tac ddng A eua tdng yeu to (i), tdc la A tren c P s d so lieu ve hien trang Oja he t u nhien - ky thuat khu VUe nghien edu;
T h U t d xac lap thang bae eudng dp tac
80^'^^lK'H^^ 7.2010
Bang 1: Bang phan cap he so tam quan trpng cua cac yeu t d anh hudng Cap dp he sd tam quan trpng cua
y e u t d t a c d d n q ( l i ) C a p l
Cap 2 Cap 3 Cap 4 Caps
1 3 5 7 9
Tieu chi danh gia mdc dp quan trpng eua yeu t d tac ddng Yeu t d rat It quan trpng
Yeu t d it quan trong Yeu t d quan trpng trung binh ' Yeu t d quan trong
Yeu t d rat quan trpng Bang 2: Bang phan cap cudng dp tac ddng cua cac yeu t d
Cap dp tac ddng cua cac yeu t o '(Ail)
C a p l Cap 2 Cap 3 Cap 4 Caps
1 3 5 7 9
Tieu chi danh gia cUdng dp tac ddng cua cac yeu t d
Tac ddng rat yeu Tac dpng yeu Tac dpng trung binh
Tac dpng manh Tac ddng rat manh Bang 3: Bang danh gia cUdng dp tac dpng tUPng ho cua cac yeu t d TT
1 2 3 4 5
Cudng dp hoat ddng K < 20 % 20 < K < 40 % 40 < K < 60 % 60 < K < 80 %
K > 80 %
Danh gia cUdng dp truot Id Cudng dp trupt Id rat yeu
Cudng dp trupt Id yeu Cudng dp trdpt Id trung binh
Cudng dp trdpt Id manh Cudng dp trupt Id rat manh
ddng tdng hop cua cac yeu td anh hUdng;
Thd nam, thiet lap ma tran djnh lupng vdi cac hang la cac yeu t d anh hudng va cae cot la he sd tam quan trpng va cap dp tac ddng eua tdng yeu t d va ket qua phep tinh trung gian I.A; I.A ;
-* ^ I jl I (I max
Thdsau, tinh toan M , M , K theo cdng
' max' ' ^
thdc{3), { 2 ) v a ( 1 ) n d i t r e n ;
Thd bay, danh gia QTTL€)D theo gia trj eudng dp tac dpng tong hpp cua tat ea cae yeu t d anh hUdng theo thang bae cudng dp tac ddng tong hpp da xay ddng.
Oe nang cao tinh khach quan djnh lupng trong qua trinh danh gia eudng dp tac ddng tong hpp cua cac yeu to ddi vdi QTTLDO theo phUPng phap ma tran djnh lupng, nhat thiet thang bae diem phai dupc thiet lap mdt each khoa hpc, he sd tam quan trpng I. cua tdng yeu to 6\Jac xac djnh tUPng ddi chinh xac tren co sd vai trd va dpng lUc tac ddng cua ehung, he sd mdc dp tac dpng A. cua ti^ng yeu t d khdng 6ugc the hien djnh tinh theo chu quan cua ngudi danh gia ma phai tren co sd cac so lieu quan trae, t h i nghiem chinh xac ve dac diem Dja he t u nhien - ky thuat khu vUe nghien cdu doi vdi QTTLDO cu the.
Ve xac djnh he so tam quan trpng cua cac yeu t d L:
He so tam quan trpng (1.) bieu thj vai trd cua yeu t d tac ddng t h d i va dupe xac lap tren eP sd phan tich, danh gia sU anh
hudng cua ehung den QTTLDO. Can edvao ban chat cua cac nguyen nhan, dieu kien lam phat sinh, phat trien QTJLDD, he sd tam quan trpng (I.) 6iJac phan thanh 5 cap (bang 1):
Ve cap dp (mdc dp) tac dpng cua cac yeu t d A,.:
Can e d v a o ddng ldc tac ddng cua cac yeu td, cap dp tac dpng A. cua cac nguyen nhan, dieu kien i (A.) 6uac xac lap thanh 5 cap (bang 2)
Trong ciing mot so nguyen nhan, dieu kien, neu ed nhieu cap dp tac ddng khac nhau thi phai xac djnh cap dp tac dpng trung b'inh eua nguyen nhan hay dieu kien do.
Thang bae danh gia cddng dp tac dpng tdpng ho cua eac yeu t d anh hudng (K) ddpc xay dung va de xuat trong bang 3 3. PhUtfng phap quy trinh phan tich he thong cap bae (AHP - Analytic Hierar- chy Process) cua Thomas Saaty
Phuong phap quy trinh phan tich he thdng cap bae AHP ddpc dng dung pho bien trong nhieu ITnh vUe kinh te, xa hdi va khoa hpc t u nhien. PhUPng phap AHP dac biet phu hpp vdi cac van de lien quan den viec so sanh hang loat eac yeu to ma chung khd djnh lupng. Npi dung ep ban cua phuang phap la xay dung he thdng cae yeu t d hinh thanh va phat trien tai bien, so sanh cap ddi tam quan trpng cua eac yeu t d dua tren tieu chuan so sanh cua Thomas
Saaty trong mdt ma tran tuong dng (xem bang 4), sau dd tinh toan ty trpng tdPng ddi cua mdi yeu to trong hang loat cae yeu t d dat ra theo edng thdc tinh toan tdong dng.
Mac du, tinh Idgie va he thdng eho mdt thang bae phan cap da ddpc nha toan hpc ngudi My T.L. Saaty (University of Pittsburgh) de cap trong edng trinh
"Fundamentals of the Analytic Hierarchy Process" (2000) [8], mot sd tac gia tren the gidi eung n h u d Viet Nam da sd dung phuang phap nay de tinh toan trpng sd.
Tuy vay, ngoai viee dng phan chia eudng dp tac dpng (j) thanh 5 cap dp, thi ngay t d ban dau khi dUa ra thang ty le so sanh tam quan trpng cua cac yeu t d tac dpng, Saaty cung da dung phUdng phap chuyen gia de so sanh han theo 5 cap dp (1, 3, 5, 7,9) va so sanh thua theo 5 cap dp (1,1/3, 1/5,1/7,1/9) tren mot ma tran vudng cap n (n la so yeu to so sanh), vdi dudng cheo chinh cd gia trj bang 1. Ma tran nay ehi ra rang, neu ehi sd quan trpng cua yeu t d A so vdi B la n thi ngUpc lai ti sd quan trpng cua 8 so vdi A la 1/n.
Ma tran phan cap he so tam quan trpng eua Saaty van mang tinh chu quan, nd dupe xac lap chi de khong che va phan djnh trj so tam quan trpng cua eac yeu td tac ddng trong khoang 0 - 1. Vi the, viec ap dung ly thuyet nay de xay dung mot thang phan cap ehung ve cudng dp tac ddng ddi vdi mot qua trinh dja chat dpng luc nao do la khdng ddn gian va edn nhieu van de, bdi cac yeu t d tac dpng cung nhu eudng dp tac dpng trong moi qua trinh khdng giong nhau nen khd ed the phan djnh mdt each tudng minh va chi tiet ve mdc dp quan trpng eua tdng yeu t d doi vdi mdi tac gia.
PhUdng phap AHP dupe tien hanh theo eac trinh t u sau:
Thd nhat, can xac djnh danh muc cac yeu t d anh hudng (a.) quan trpng can dua vao ma tran danh gia;
Thd hai, thue hien phan ti'ch, danh gia, xac djnh tam quan trpng cua tdng yeu t d va so sanh cap ddi yeu t d (a,) (bang 5);
Thd ba, xac djnh gia trj trung binh nhan eua tdng hang (m.);
Thd t u , xac djnh trpng sd (ty trpng tUPng ddi) eua eac yeu t d id)
Thd nam, thiet lap thang diem sd mdc dp, cddng dp tac ddng cua cae yeu t d (bang 6):
Thd sau, tinh toan ehi sd tich hop eua eac yeu t d tac ddng (S);
Thd bay, thiet lap thang bae danh gia tong hpp ehi sd tieh hpp eua cac yeu td tac ddng (bang 3);
7.201 O^IDSIinSSl I g t
Bang 4: Thang ty le so sanh cap ddi tam quan trpng cac yeu td tac ddng theo Saaty
Yeu to tac ddng (Ldp thanh phan)
Quan trpng nhunhau
<<< Quan trpng thua Quan trpng
thua it Quan trpng
thua vda Quan trpng thua nhieu Quan trpng thua rat nhieu
Quan trpng nhunhau
1 1/3 1/5 1/7 1/9
Quan trpng hpn > » Quan trpng
hon it 3 1
1/3
1/5
1/7
Quan trpng hPn vda
5
3
1
1/3
1/5
Quan trpng hon nhieu
7
5
3
1
1/3
Quan trpng hpn rat nhieu
9
7
5
3
1 Khoang trung gian gida eac mdc dp tren cd the sd dung la: 2 , 4 , 6 , 8 .
Thd tam, danh gia QTTLOO theo gia trj chi sd tieh hpp eua cac yeu td tac ddng va thang bae danh gia tong hpp chi sd tich hop da ddpc xac djnh.
Ghi chu:
a^ (a,, a^..., a j la cae yeu t d tac dpng a.j la ket qua so sanh cap ddi tam quan trpng gida yeu t d a, va a, tdc la a, = a, /a
Trpng so (ty trpng tuong doi) cua cae yeu t d (di) dupe tinh theo cdng thdc sau:
m,
(5)
d =
• Z > i
Trong do:
6^ la trpng sd (ty trpng tuang doi) eua yeu to tac ddng a,
m. la gia trj trung binh nhan cua hang t h d i
n, =;yi*a,2»a,.
=Vv^
- °2n-1 *^2n-fa n
Theo phupng phap quy trinh phan tieh he thdng cap bae AHP cua Thomas Saaty, kha nang phat sinh, phat trien tai bien trupt Id dat da tai bat ky mdt diem nao trong vung nghien cdu dupe d u bao theo ehi sd tieh hpp cua cac yeu t d tac dpng va dupc tinh theo edng thdc:
s=z:,d,*x,
Trong do:
(6)
S - Chi sd tich hpp eua cae yeu t d tac ddng;
X. - Diem sd the hien mdc dp, eudng dp tac ddng cua yeu td a^ ddpc xac dinh theo bang 5.
N la sd t d nhien khae 0; Viee chpn
Bang 5: Ma tran so sanh cap ddi tam quan trpng gida eac yeu t d tac ddng
ai 32 33
an-1 an
ai 1 asi a3i
a„.ii ani
a2 ai2 1 a32
a„-t2 a„2
33
a i 3 a23 1
an-1 3 an 3
an-1 ain-1 a2n-l a3n-1
1 ann-1
an a i n a j n a3n
a„-i„
1 Bang 6:Thang diem danh gia bang diem sd mdc dp, cddng dp tac ddng cda cae yeu to
STT 1 2 3 4 5
Mdc dp, eudng dp anh hudng cua cae yeu t d tac ddng
Khdng thuan Ipi it thuan Ipi Thuan Ipi
Tuong ddi thuan Ipi Rat thuan loi
Oiem sd 1/9 hoac 1/9 *N 3/9 hoac 3/9 *N 5/9 hoac 5/9 *N 7/9 hoac 7/9 *N 9/9 hoac 9/9 *N N la sd t u nhien khac 0; Viee chpn thang diem ndi tren nham thdng nhat vdi phuong phap ma tran djnh lupng va tUPng thich khi ddi sanh gida 2 phUPng phap.
thang diem ndi tren nham thdng nhat vdi phuang phap ma tran djnh lupng va tUPng thich khi ddi sanh gida 2 phuong phap.
4. Doi sanh hai phuorng phap ma tran djnh iuong va quy trinh phan tich he thong cap bae AHP
4.1. Ket qud tinh todn theo phuang phdp ma trdn dinh luang
Do cung thdng nhat mot thang bae ve cudng dp tac ddng eua cae yeu t d nen Ai j max cua cae yeu t d thUe chat la gidng nhau va la gia trj Idn nhat trong thang bae dd, nen ket qua K theo edng thdc (4) la:
trinh phdn tich he thong cdp bgc AHP Neu phuong phap phan tich, danh gia, xep loai gidng nhau hoac tuong dUPng nhau, thi thUe chat gia trj so sanh cap ddi tam quan trpng (1.) gida cac yeu to (a,) theo bang 5 la:
(8) Tdc la:
K = - * A , +I2 'Ai,-hi * A „ • + I „ * A , . {l1+l,-^l3-^....g»A„, (7) 4.2. Ket qud theo phuang phdp quy
a,i = I A a,3 = I A - a2, = l2/li a,3 = l/l3...
a„, = lyi,
an3 = l n / l 3 -
ai2 = I A a i n = I A
322 = 12/12
32„ = I A
an^ = l„/l
^nn = 1 / I
82^l^ifiEKlSil 7.2010
D i O d l j T
I'l '2 I3 ' l„ ' V l i * l 2 * l 3 * . . . * l „
m, = n i * i * - k » . k . ' 1
*— =Nn|/'1 I2 I3 ' l„ ' V l , * l 2 * l 3 * . . . * l „
k A » k * Jn
- ^ = L n ,I 1 1 1 " V l * l * l * * l
' 1 ' 2 ' 3 ' n V ' l '2 '3 - 'n
Trpng sd (ty trpng t u p n g ddi) eua cac yeu t d (d|) ddpc cu the n h u sau:
l,n|
( I l + l 2 + l 3 + - + ln)*f, ll
•(l,-l-|,-H3-|-...-hl„)
1 I * l * l * *1
1, I j I3 ... I„
l,n.
d , = -
1 I *l *1 * *l
1, 12 13 ... i „
1 I • I »l » *|
I, i j ij ... i„
I, (l,-Hl2-t-l3-^...-H„
Lr, 1 I *1 *1 * *1
'1 ' 2 '3 ••• ' n
1
In (l,-H,-H3-^...-H„)
TU edng thdc (6), chi sd tich hop eua cac yeu t d tac ddng se la:
^ *X,-i-
X, ( I l + l 2 + l 3 + - + l n ) '
I,
(9)
+ != *x„
{l,+l,-H3-H...-H„)
Mat khac, thdc chat gia trj diem so the hien mdc dp, cddng dp tac ddng cua cac yeu td (X.) la:
Y _ ji V
Ai - T neu chpn thang diem cd gia
jimax
trjXi < 1,hoac (10)
X = — L » | M neu chpn thang diem cd ' A
gia trj Xi > 1 (11)
(N la so t u nhien bat ky khac 0, phu hpp vdi thang chpn va tUPng thich vdi tdng loai hinh dja ddng lUe va tai bien dja chat)
Tdcae cdng thdc 9,10, 11 , ta cd:
S = ^ * ^ ^ . (l,-|-lJ-^l3-|-...-|-l„) /\-^;„,„
+ h *^^+ + (l^+l^+l^+... + l j Aji„3, (12)
L . A,„
( l , + l , + l 3 + . . . + l„) A,^^
neu chpn thang diem cd gia trj X, < 1, hoac
^ _ I / A „ + l 2 * A , , + . . . + l„*A^„
H,+h+h+•••V*^.,. (13) neu chpn thang diem ed gia tri X. > 1
So sanh cdng thdc 4 vdi edng thdc 12 va 13, thay rang K va S deu eung nhan mot gia trj n h u nhau K = S neu chpn thang diem ed gia trj X. < 1, hoac tuyen tinh ty le S = K*N neu chpn thang diem cd gia tri X , > 1 .
So sanh hai phuong phap ndi tren, thay rang phuong phap ma tran djnh lupng tinh toan dPn gian hon nhieu so vdi phuang phap quy trinh phan tich he t h o n g cap bae AHP cua Thomas Saaty nen ddpc khuyen cao sd dung.
Qua trinh trUOt Id dat da tren sUdn doc la tai bien dja chat phde tap can phai dupc phan tieh danh gia t d n g hpp tac d d n g tdPng ho gida eac yeu t d anh hudng (nguyen nhan va dieu kien) trong mdi quan he tong hoa gida t d nhien va nhan sinh, trong mdi quan he tac ddng bien chdng qua lai gida cac yeu t d ed lien quan hdu ed. Chinh vi vay can phai xac dinh dung, du cae yeu t d anh hudng quan trpng nhat, dac trUng va dai dien eao ke ca eho mdt sd yeu t d tac dpng true tiep hoac gian tiep khac, nhat la he sd tam quan trpng eua eac yeu t d anh hudng va thang bae danh gia tong hpp phai dupe xac djnh tren cP sd khoa hpc va phu hop vdi ban chat, nguyen ly ddng ldc cua cac qua trinh t r u p t Id dat da tren sUdn ddc, mai doe vung mien nui.
Cudng dp tac dpng tdPng ho cua cae yeu t d anh hudng den qua trinh trupt Id dat da tren sUdn doe, mai ddc vung mien nui theo phuong phap, thang bae da 6uac xac djnh va de xuat n h u tren can 6uac djnh lupng chinh xac tren co sd sd lieu ve cap dp tac ddng cua cac yeu to thudc dia he Tu nhien - Ky thuat khu vUc nghien cdu.
Viec lua chpn phupng phap ma tran djnh lupng de danh gia cudng dp tac ddng t u o n g ho cae yeu t d anh hudng den cac qua trinh dja ddng lue va tai bien dja chat ndi chung va qua trinh trUpt Id dat da tren sUdn doe, mai ddc dudng giao t h d n g mien nui ndi rieng la hoan toan phu hpp va tien ich.
TAI LIEU THAM KHAO
1. Le Thac Can va nnk, Banh gia tac dong moi trifdng - Phaong phap luan va kinh nghiem thtfc tien. Hue, 1997.
2. Cue Moi trirdng, Banh gia tac dpng moi tracing (Phong theo ban tieng Anh cua ALAN GIFPIN), Ha Npi, 1995.
3. Nguyen BiJc Ly. Nguyen nhan, dieu kien lam phat sinh va phat trien cac djch chuyen trpng lUc dat da tren suon doc. Tap chi thong tin khoa hpc va cong nghe Quang Binh so 01/2008.
4. Tran Manh Lieu. Mot vai phi/ong phap danh gia djnh tinh va djnh lUpng vai tro cua cac yeu to hinh thanh va phat trien tai bien dja chat. Tuyen tap bao cao hoi nghj khoa hpc lan thi) 18 -Tri/dng Bai hpc M6-fija chat, 2008.
5. Nguyen Thanh. Tap bai giang danh cho hpc vien cao hpc chuyen nganh dja chat, Truong Bai hpc Khoa hpc Hue, 2007.
6. B.Nilsen. New trends in rock slope stability analyses.
Bulletin of Engineering Geology and the Environment, Springer Berlin / Heidelberg-France 4/2000,2000.
7. Saaty T.L. Fundamentals of the Analytic Hierarchy Process, RWS Publications, 4922 Ellsworth Avenue, Pitts- burgh, PA 15413,2000.
