TapchiKhoahoc DHQGHN, iOioa hpcTvnhien va C6ngnghe,T|p29, So 3 (2013) 30-39
Nghien cuu mo hinh vung tham trong than de, dap bang phuong phap dien da cue cai tien va Ra da dat
Vu Due D o A n h Chung^
'TrvoTig Dgi hoc Khoa hpc Tv nhiin. DHQGHN, 334 Nguven Trai, Thanh Xudn, Hd NqL Viet Nam
^Vien Sinh thdi vd bdo v? cong trinh, Vien Khoa hoc Thuy L^i Vi(t Nam
Nli|n ng^y 29 Ch^g 11 nlm2012
Chjnh silang^y 14 th ^ g 12 nam 2012: chap nhan dSng ngay 28 thang 30 nSm 2013
Tom tit: Bai bio trinh b ly mpl so ket qua Q'nh toin mo lunh thuyet v i th\rc le doi ved vOng tbim trong thin d i dap khi ip dong c ic kien tbiic Toin hoc, V ii v i phan m lm Earthlmage 2D (dot voi pbuTOTig phap di?n da cue), phan mem Reflex (d6i vdi phuong phap Ra da dit). D6ng thoi cung Uinh biy c ic ket qua nghiin cuu lua chon h i cue do tdi uu tir c ic loai hg ctre do khac nhau cua phuong phap dign da cue doi voi mo hlnh IJ dtuyii v i ihuc te. Tu dd nSt ra c ic ket luan v i hien qua ip dung cua phuong phip Ra da dat va phutmg phap dien da cue cat tien vdi he cue tdi uu doi voi vide tim kiem. x ie dinh vitng tham; dong thdi tim ra phuong phip tien hinh cong tic ngoii tbuc dia sao cho phi) hpp. C ic k^t qua nay da duoc ip dung ihu nghigm trSn viing thim thuoc Kd M J Trung doan tir KO+00 -r K2+400 thuqc de ngoM huu s6ng D io, huyen Vu Ban. tinh Nam Dinh.
Tir tnroc din nay hiu nhu chi phit hi?n cac vhng tham trong than de dap thong qua cic bilu h i^ tham ra b€n ngoai, khi d6 vilng tham da gay anh huctng kbong nho din sv an toin ciia de dap. Mat khac, nbfhig bieu hidn ben ngo^ ly kbdng the giup ta chi ro vj tn cua vung thim d l xii ly nen khi xii ly phai khoan thim d6 ril tin kem. Vi vay, vide xac djnh dutyc vi tn' va qui mo cac viing ±am trong thin de djp II rit quan trong, giup chung ta lira chon dupe gtai phip xil IJ hOu hieu nhirng vung thdm niy.
Chung t6i da tiln hlnh nghien ciiu nhlm sir dung t6 hop phuemg phip di|n da eye cai tiln 11] va Ra da dIt [2,3) dl phit hien vung thim trong thin dS dyp thfing qua viec lira chon, nghign ciiu, tmh toin mo hinh I;? thuylt v l thyc te ^ i voi viing thim trong than de dap; n ^ e n cuu thii nghiSm ti'nh toin lya chpn he cue do i6i im tu cac loyi h? eye do khic nhau ciia phuong phap dien da eye [3-5] doi vdi mo hinh ly thuylt va thyc te. Tu dd, tim ra phuong phip tiln hlnh c6ng tic ngoli thyc dja sao cho phu hop. Cac kit qua nIy d i duye ip dung thii nghi?m trSn thyc tl
V.D Mink. D.A. Chung /Top chi Khon hoc DHQGHN. Khoo hoc Tir iMen va Cong nghS, Tap 29, So 3 (20J3) 30-39 31
2. Qua tn n h nghien cihi mo hinh thuylt va k it qua
2.1. Lua chon mo hinh ly thuyit vUng tham K it qua DghiSn cihi, khao sdl dja chit tiong vimg dong b ^ g song Hong cho thay, dai dap de chii y lu la d ll bdi ling c6 di|n trd suit tCr 14-40J2m. Vung thlm trong than de va dap trong thuc te thuong c6 chieu rpng vai met den v k chuc cd chilu sSu vM m it din chuc met so voi m^t de, dap. Cho din nay khong c6 mpt mo hinh thuc te ci,] ih l n^o cua vung thlm cu thi vi khi phat hi|n dugic ihi xii ly khoan phut ngay.
Tu thuc te do chiing toi chpn md htnh vung tham, ro ri c6 d ^ g Idp kdo dai, can ddi. Lop tham c6 chieu day (d) Ih 0,5m, (D) la 20m va nam sau (h) 2m so vdi m^it dit. Vung thlm la d it am cd dien trd 1^ lOOm, ndm trong moi tniong dIt dap de cd di|n trd 1^ 20$2m (hinh 1)
d n
Hinh I. M6 hinh ly ihuyet vimg diani.
2.2. Tinh todn l{ta c/ipn hi cue toi uu trong phuang phdp diin da cve edi lien ddi vai md hinh ly thuyit vung tham
2.2.1. Hi di?n ofc dipole - dipole TrSn tuyin tinh ly thuyit doi v6i mS hinh ly thuyit vCing thlm, chiing t6i tiln hhnh tinh cho he di|n eye dipole - dipole voi ^ I , n=8 dya tren phin mem Earthimage 2D [4],
Hinh 2 (trong dd (a) Id kit qua tinh thupn;
(b) Id kit qua gidi ngifftc: (c) Id mo hinh tinh ihuanf ket qua tinh ly thuyit doi vdi md blnb ly thuyit vimg tham the h i|n khu vyc tham la vung di thuong d i|n tro tbip, nhimg tren k it qua tinh nguyc (b) cho ihly vung nay cd chieu dhy Idn hon chieu d ly thyc, khong phii hop vdi rod hinh da dua ra nhu mo hinh tinh thuSn (c). VI v|y, vdi h | eye nay khdng xdc djnh dupe chieu dSy cua vimg thlm.
,i(tfVtnh hinh Jy cibuylt vhng tham cho h | eye dipole-dipole.
32 y.D. Mmh. D A Chung /Tap chi Khoa hpe DHQGHK Khoa hoc Tit7>hihi va C6ng iighl Tap 29. So 3 (2013) 30-39
2.2.2. H i diin cue Wenner Chung t6i u6n h ^ h tmh ly ihuyet cho h§
di?n cue Weoner dua trSn phan mem Eanhimage 2D ddi voi mo hinh oeu trSn hinh 1.
Hjnh 3 la m pi vi dy mmh hoa k it qua tfnh toSn d6i voi mo hinh thuylt vung thim (trong did {a) la k it qua t(nh ihudn; (b) Id k it qua giai nguoc; ic) Id md hinh tfnh).
— 1 ' I f :
...
Hinh 3. Ket qua ti'nh <J6i voi mo hinh IJ thuyet vung than) cho h| cue Wenner Kei qua tmh ly thuyet voi he cue Wenner
cho thay voi he cue nay be mat trSn cua m6 hinh u'nh toin dung voi m6 hinh 1}? thuyet. Tuy nhien, chieu day ciia vung thim l(5m hon nhiiu so v6i mo hinh.
2.2.3. H i diin Citc Wenner ■ Schlumberger Chdng t5i tiin hanh rinh ly thuyit cho h?
dien cue Wenner - Schlumberger c6 a= l, n=8 dua tren phJin m^m Earthlmage 2D doi voi mo hinh nSu trSn hinh 1. Hinh 4 la mot vi du minh hpa ket qua ti'nh todn doi voi mo hinh vbng thim (trong do hinh (a) Id k it qua tm h thudn;
hinh (bj Id ket qua gidi nguac. hinh (c) Id m3 hinh tinh).
□ I ■
I
Synthetic Moael
Hinh 4. Kit qua tfnh d& vdi m6 hinh ly thuySt vhngthSm cho he circ Wenner- Schlumberge
V D. Minh, D A. Chung /Tap chi Khoa hoc DHQCHN, Khoa hoc Ttr iibien va Cong nghe. Tap 29, So 3 (2013) 30-39 33
Cac ket qua u'nh loan bM loSn t h u ^ cho h§
cue Wenner - Schlumberger u en mo hmh tham th^ hi§n trong m jt cat di?D erd nhu sau: Dj thuoDg di?D trdr th ip c6 d&ng via ngang. Chi^u sau d in dinh phu hgp voi mo hinh. Nhung chieu day cua dj thuong 1cm hem so vdi md hlnh.
2.2 4. Nhdn x e t chimg
D6i vdi nhiJng d6i tinjog 11 vilng th im hay via ngang c6 the su dung cac h | cue W enner v i he dien eye W enner-Schlumberger d l tim kilm , tuy nhidn dj thuong th i hien ro hon khi do bSng he cue Wenner
2.3. Tinh todn cho h i cjrc Wenner doi vdi mo hinh ly thuyet v«ng thdm thay doi
Chung toi tien hanh tuih todn cho he c\ic Wenner vdi mo hinh tham la via ngang 6 c ic d$
siu thay ddi. Ldp thim cd chilu day (d) Id 0,3m, dM (D) Id 20m v a ndm sau (h) duoc tSng
dan tu 2m so vdi m at d it d in khi ndo khdng con di thuong. Viing thim la d it dm cd di?n trd 14 lOOm, n4m trong mdi tiudng d it d ip dS cd dien trd 14 20C^m. Sai s i k j thudt dugc ti'nh 14 3%.
T(nh toan ly thuylt mo hinh vung th im (via nam ngang) vdi cac chilu s4u khac nhau (hinh 5 d in hinh 7) cho tiiiy: Vilng tham cd chilu d4y 0,5m, chieu d4i 20m n im d dp s4u <3,2m thl cd thd xac djnh dupe chieu sau cung nhu vi tn ciia vung thim . T ilp tpe tang chieu sau d in 3,6m (hinh 6 ) ihi k it qua d'nh to4n khdng chi ra dupe dj thuong cua viing thim .
Tu ket qua thu nghipm viing thim la via ngang tren md hinh ly thuyet vdi cac he cue v4 chilu sau khde nhau. Chung tdi th iy rin g d l khao sat viing thim tren than de dpp nen su dung he eye Wenner vi cd th l x4c dinh dupe vj cri v4 chilu sau vung tham khi chilu siu vilng tham <= 6 Ian chieu d iy viing thim.
Hinh 5. Kit qui tinh doi ven md hinh IJi thuyet viing thim 2.4. Thir ngbiem md hinh I f thuyet vung tham
vdi phuang phdp Ra da ddt
Su dung phan mem Reflex thu n g b i|m kha nang xac djnh md hinh ly thuylt 14 1 via ngang
(hinh 8) vdi h4ng so dien mdi cua mdi trudng 14 20 va viing thim la vilng ngam no nude nen chdng tdi t^m ti'nh hang sd d i|n mdi 14 40.
34 V.D Mmh, D.A. Chung/Tap chi Khoa hoc DHQGHN, Khoa hoc Ta iiJiifn va Cong nghl Tip 29, So 3 (2013) 30-39
Hinh 7. Ket qua u'nh 46i voi m6 hlnh Jy ihuyet vCing [ham vin h = 3.6m.
Hinh 8. Ket qua linh doi vm m6 hlnh IJ thuylt vting thim c6 chi^u sau 2m vdi phircmg ph&p Ra da d4t.
V.D Minh. D-A CJniiig /Tap cM Klion hoc DHQCHN, Khoa hoc Tir ii/iieii vi Cong nghe, Tap 29, Sd'3 (2013) 30-39 35
K€t qua th j nghi^m voi phuong phdp Ra da ddt de xac djnh via ngang cho thay vm phucmg phap Ra da d4t cho chung ta d) thuong vdi chiiu siu va cbi^u day ciia via ngang niong doi chi'nh xac. dSu cua ddi tu(?ng c6 1 d) thir&ng
'A
paraboi gidng nhu di thuong ciia ddi tugng diim.
Khi tSng chilu sau ddi tuqng Idn 3m (hinh 9) thi thay ring dq Ion bien d$ cua sdng
X
9
trSn m |t ranh gioi song p h ^ xa nhieu Ian deu nho hem rit nhieu so voi khi ddi tugnga
chieu sau 2m. Vi vay khi ddi tirgng cr sau va mdi miODg c6 dien do suat ifaap rat khd cd thI dinh gid tren md hinh ly thuyet can phai ihii nghiem tren md hinh thiic td mdi cd the danh gid chinh xac kha nang kbw sat ciia Ra da.
Hinh 9. K^l qua tfnh d6i vcii md hinh If thuyet vilng tham cd chieu sau 3m vm phirong phap Ra da dlt 3. Qua trinh thir nghiem thuc tl k it qua
3.1. Phuong phap di?n da ofc cat liin 3.1.1. D\a diim vd phifomg phdp tiin hdnh
-
Dja didm ap dpng thCr nghi?m dirqc liln hinh tai K6 MJ Truog do^in ttr KOfOO -r K2+400 thuQC dS ngoii hQu sdng Dio. huy^n Vy Ban, tinh Nam Djnh (hinh 10). Qua didu tra khao sat ^ i khu vyc niy bj thim doyn tit K2+200 din K2+300 dii khoang 100m. T?i day chdng tdi bd tri 6 tuyen|Jo|d9
c|d e^aomat cit tai ria mSt dd phia sdng va ria mat de phia ddng.
• Thiet bj duqc dung la he thilt bi dien da eye Super Sting R1 [5] vdi he eye Wenner, ki'ch thude h§ eye 2m
- Hd thing tuyin do duye bd tri nhu sau.
Bo tri ede tuyen ngang qua khu vuc cd tham (doc theo dd) dl xac dinh chieu dai, chilu sau nlfl v h n o tham
36 VD M mKDA Chung/Tap chi Khoa hoc DHQCHN, KJioa hoc Tinihienxia CSngnghe, Tap 29, So 3 <2013) 30-39
3.1.2. K it qua
Ket qua tren 2 cuyen do T1 va T2 tr€n mat dS (hinh 1] va hmh 12) the hien ochiSu slu 2m tir met thu 12 den cuoi tuyin do (K2+212 — K2+254) la vimg c6 d i ^ trcr suit thSp tu 4-10 Qm th£ hien day la vCmg th4m m ^h .
KSt qua tr6n doan K2-f248-K2-H302 thi hien a tuy^n T3 va T4 chi ro vung thdm tit dau tuySn den met thii 30 cua tuyln do (tu K2+248- K2+278), vimg th4m nay cd chieu slu 2m so vdi mat de. Ngoai ra trSn 2 tuyeo nay cung thiy
dj thuong di?n tro thip thi hien la vung thim a met thii 44 va sau 2m.
Tren 2 tuyen T5 va T6 chi thiy xuat hien di thuong dien trcr thip tm tuydn T6 la tuyin tren mgt ria dl phia song the hi|n dly khong phai II di thuong cua vung thim >4 nd khdng kdo tu phia song sang phi'a dong.
Qua kit qua khao sat in hoa trSn kl My Tmng cho thay ttd day cd vimg tham manh tir K2-I-212 - K2+278, chilu slu 2m so vdi mSt de (xem hinh 13).
D>S
Hinh 11. Ket qua khao sit tai tuyin de phfa s6ng nisniastiiiaiq qih atxi£irti|iii&;
Hinh 12. Ket qua khao sat tai luyin de phfa dong Mil phia &
6
nsTIH
i^ ..
.T
6
Mil Phia done Ghi chd
T
1
.T2
T3
- - VilrfciciuySikhaojit Hinh 13 Binh d3 v\ trf tuyen do vl khu virc thim.V' D- Miii/i, D.A Chung /Tap chi Kltoa hpc DHQGHN, Khoa Iwc Tie n/iilti ua Cong iighl Tap 29, So'3 (2033) 30-39 37
3.2. Phum g phdp Ra da ddt
D fch g ii kha nSng khao sSt ciia phuong phap R a da d lt chdng t6i h M i xay d\mg m o hinh thuc vcti 3 lo?d v$t li|u khac nhau
bao gom c6 1 khoi d lt s6t voi di?n trb suit lOHm, mpi khoi dat d^i c6 dien tid suat lOOOm va I khoi cat pha c6 dien trd suit 500£2m (hinh 14).
""
Hinh 14. Mohinh thii nghiem chieu sau b&u dung cuaphuang phdp Ra da vcri cac khoi dat khac nhau.
Ket qua thii nghi|m bang ten 200 Mhz qua khdi set co di^n trb su it nhb lOQm cho th iy Idia n m g khao sdt ciia phircmg phap Ra da d lt chi d£n diT(7c chilu sau Im (hinh 15)
Ket qua thii nghicm bang 5ng ten 200 Mhz qua kh6i d lt d6i cho thIy c6 th i khao sat dupe cac doi tupng n^m 6 chieu sau 1cm hon 3m b
d ilu k i|n d lt da c6 dipn trb suat k h o ^ g lOOHm (hinh 16).
Ket qua thii nghipm qua khoi cdt pha cho thay ven ling ten 200 Mhz vln thiy c6 tin hieu manh ciia s6ng Ra da a d$ sau den 6m (hinh 17).
Hinh 15. Kit qua thii nghiem trenkhlisdt ang ten 200 Mhz
38 V.D.MM, D.A. Chung ITap chi Khoa hoc DHQGHN,tOK«ihKTirnhten va C6ng tight. Tip 29, So 3 (2013) 30-39
Hinh 16 Ket qua ihir ngbiem qua khoi <3ai d6i bing ang ten 200 Mhz.
H5nh 17, Ket qua ihir nghiem qua khoi cStphabinging ten 200 Mhz-
1. D6i vcri h$ eye Wenner
- Co the xac dinh dupe chinh xdc vj in' cung nbu chieu siu cua vOng thlm.
- Sir dyng h? eye niy e6 thi xic dmb duac viuig tham sau hon 6 Ian so vdi chieu day virng tbini.
- H? eye Werner Ik he eye phu hpp nhit dS khao sat vung tham vi via ngang trong than dS, dap.
2. d6i vcri h? eye Wenner - Schlumberger Co the xac dinh dupe chinh xic vi tn' cung nhu chieu sau ciia vung thim la via ngang.
3. Dot vcri h? eye Dipole - Dipole Sii dung hp cue nay khi khao s4t vCmg thim thi di thuemg vung thim bj biSn d?ng so vdi mb Wnh nen rit khd c6 thS xac <£nh dupe vung ihim.
4. Phuemg phap Ra da dat c6 the xdc djnh dupe chibu s ^ va chibu diy ctia cic via ngang.
V6i phuemg phap Ra da dit rat khd dp dung dupe cho moi trudng c6 dipn ud suit thip dudi
V D. Mm/i. D.A Chung/Tap chi Khoahpc DHQGHN, Kiioa hoc Tirnhien tw Congnghe, Tip 29, So 3 (2033)30-39
10£im, nbung c6 th6 dgng t6t d6i voi moi trucmg CO di?n tro suit cao Ion hon lOOHm.
5. Nhu \%y. qua nghien ciiu cho fliay vice ap dung phuemg phap diin da epe cm nin khi sii d\mg he ctfc do IS Wenner vS phuemg phdp Ra da dat hoSn toin c6 hieu qua d6i voi vi^c tim kiSm, phdt hien cSc doi tupng vung tham irong than de IS cac via ngang vS cd thi xSc djnh dupc ranh gidi tr&n va dutt ciia via ngang dd bSng phuong phSp Ra da dit.
TSi iieu tham khao
[1] Vu DUc Minh, 2010. “Phuemg phap Tham d6 dien da cue cai ti6n". Tap chi' khoa hoc Dai hoc Qu6c gia Ha N$i. Khoa hoc To nhien va C6ng ngh«, 26(2010), tr 233-241
[2] Stewart N, Griffiths H , Ground Penetrating Radar - 2°*' Edition, MPG Books Limited, Bodmin. Cornwall. UK, 2004.
[3] Vu Due Mmh, Nguyen Ba Duan, 2007,
"Application of methods of Ground Penetrating Radar and of Multi-electrode Resistivity Imaging to discover old road foundations around Doan Mon vestige”, VNU Journal of Science, Earth Sciences, 23(2), p. 126-135.
[4] Advanced Geoscienes, 2002, “Eanhimager 2D resistiviiy and IP Invesion", Advanced Geosciences me. Austm, Taxas.
[5] Advanced Geoscienes. 2000-2009. 'The SuperSting™ with Swift’'* auiomaiic resistivity and IP system hstniction Manual". Advanced Geosciences me, Austin, Taxas.
Study of Seepage area Models in Dams and Dikes by the Improved Multi-Electrode Resistivity Imaging and Ground
Penetrating Radar
Vu Due M in h \ Do Anh Chung^
*VWI/ University of Science, 3S4 Nguydn Trai. Thanh Xuan, Hanoi, Vietnam 'ht.\nui!e (>! Ecology and Works Proiection.Vietnam Academy for Water Resources Ket qua bai b w uly thu dupe trong qud
irinh thirc hi^n nhdm B eSp DH(}GH\, ma so QG.l 1.03. Chung toi xin tran tnjng edm
Abstract: This paper presents some main results of the theoritical and physical models for seepage area in dams and dikes in conjunction with application of Mathematics, Physics and Earthlmage 2D software (for the Multi-electrode Resistivity Imaging method). Reflex software (for the Ground Penetrating Radar method). Also, it shows results study of selecting the optimal measuring array from different measuring arrays of the Multi-electrode Resistivity Imaging method for the theoritical and physical model. From those experimetnts, we conclude about effectiveness of applying the Ground Penetrating Radar and Improved Multi-electrode Resistivity Imaging methods with the optimal measuring array to locate and identify the permeable areas, as well as the method used in field trials as applicable. These findings have been applied to test on a seepage area in Tmng embankment from KO+00 to K2-f400 outside the dam of J).;" river. ^ u district. Nam h | province.
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