Using CPT to Estimate an Aquifers Heterogeneity

1 Pages·0.668 MB·English

by  A. Tillmann, Z. Nyari, A. Englert, I. Fejes, J. Vanderborght, H. Vereecken

Using CPT to Estimate an Aquifers Heterogeneity
`' A. Tillmann', Z. Nyari2, A, Englen', l. Feje1)Agrospherelnstitute(lcG-lv),Forschungszen2)EötvösLorandGeophysicallnstitiiteofH
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1. Motlvatlon 111. Deslgn ot the CPT survey lv. Generallzed l D layered model V. Grain gize analysls from boreliole oores
Wo want to investigato tho aquifors hoterogen®ity in dotail. In 2003 and 2004 a cen`rBl anea of 30x20m of tho Krau[hausen test site First step for data interpretation was generating a gonoraJizod 1 D The gmin sizo distribution i§ known fmm boreholos 807, 822, and 832 in
Thereforo we choose tho CPT method sinc® it is capablo to give a was investigatod by 78 cono pBnetration lests down to 16m dspth. Tho model by stack]ng all CPT log8, i.o. mechanical cono nesistance cr , depth inton/als of 20cm. A well known relationship to dorive tho hydmulic
spatial dense sampled da]a set of physical proponies by figuro shows the CPT looations as well as the 3 completely sampled natural gamma actMty 7, bulk donsivpb. dry imtrix densitypm, water conductivity from tho graJn giz® dislribution is published by Bialas and
quasi in situ moasurements in minimal distun)ed soil boreholos wmin tho invostigation area. These boroholes were surrounded content 0, and eloctricaJ msi§tiviy p. Kleczkowsld ( 1970), \Ahsre fol]owing mlation was found:
Since tho heteT\ogeneity of tho hydraulic conductivity ig most b2 ym towtoor os.r throo CPTs wfth a dislanco of less than 2 metors. TOhno ' hfiog uloroft ghhaonwds g tihdeo r ®ofs tuh oti nfgig murooa tnh ve aoJniieedsi amnedn sstiaonndaal rlda ydeerveida tmiOondse. K = 0.0036 d£3
imporiant for hydraulic applications, we have to derive an ostimationolitfromCPTsoundingg.11.TheCPTmothod is shown consisting ot 6 1ayors over a halfspac®. Tho olovation of tho where d2o is tho 20th porcontile of the cumiilalivo gmin sizo distribution.
® :8®Cnp.'L=äncs: lTahoy greournd bwaoteruqAn®d.c,„aJ:r2iit-o®DsE aiEs•:l. Hogvivoel nis tomgaorkthoodr w witiftihhm aitb9l 9utoanl'dnarod d.e v iHa!ion. Tinh we fhiigcuhr oth soh 2ow0tsh opne rtohoe nlotiflte hiagn md asTidkoe dth aog c wLihmftuel alilni\o/o. Tgrhaei no sstiizmo adtiesdtr ihbyudtr'iao"nc,
- natural gamma actMty conduct^/ity is shown on üie right hand side.
- gamma<]amma log 1 1 \ ä ! 'a)] 1 1 -- -
•,o--------+-------`'~-'.rmJ.. -nout.oniog
A hydraulic dovice pushes a str[ng of pipos in`o tho ground. A closs spaoed „
measuroment ol tho mechanic cono msigtanca and ®lectricaJ rosigtMty are
camed out dunng tho pushing process. Aftor tho pii§h procesg radioactive - 1 5 oloclrical rogigtlvity log
pammeter§ were moasured insido the pipes. •,-" .n. r -,q .,
70-=-:--,6o ..-.i -. --- . --: - - 0.
/ i i`* FjeldeqPuiippom ofnotr: insoiling E • '. . - ' ' " m +."`.-"®i:~ . : ; i"£ ¥ ` . . ~. - . t + - 1 -61.33.m3mmaavxeimmguomdodpotphlh
radjoactivo probos -,u.d-`'t_ .`, ._ F-o 2 1 \ _ - - 5 o F ' : a zE~
`' 4 \ *F\.\ f3o:':s`,*;"#fi:Uum:':nen, =~
.- ._ ,_ L J-®,`.t.,;w`._u.,..-J- . -u
NjüEH L5qq ::o=:ua:d:n:u:hm©n, _2o
W +T 00 -:'oo:0-::.,:-.,-»?0.,do |0-. ,0- m3 |0u m?
H"::
*.,t}-E_ -H,.\ UÖ t~ c[ pn) ,iL) .`Bmt p.Danl . Bü püm)
- . -----:: .- d|mi| Kh lnD-'I
Stacked CPT logs and the statistical distribuüon of the values.
807 822 D32:-.i¥ :
Vll. CharecterlzatlForstatisticalcharacterion of heterogeneltysationofheterogeneitythe estimated vari-
Vl. Estimation of hydmulic conductMty trom CPT dataSincemtheoreticalmlationshipbotwoenCPTdataandhydmulicconduc+t.'.'lablrrolad'ch.edAsh.thfiuro
Shifling tho contor of tho investigated depth int®ival we obtain a
ogram V(|d±|) from the experimental data set is usecl: functiori of maximiim, moaj`, a.id minimum comLatk)n length ad
lvltylsaval o,aco lonapproa lgus . sownln elgbek)wthaCPTdstaisnearlynormaldistflbuted,whiletho20thpercontilo tho preteTential direction versug elovation as shown in tho figurob®low.
"g02oo~,\\,J\',,~ v(,d=,, -±ä(z(=,,-e(-„
is log-nomal distnbutod. Thoi.oforo wo us® th® docadic [oganthm of cboforamultiploLinea.regressionwiththeconeresistanco,gammaactivity,
Comiation iomtr` Azlmuth ol max. comlailm lono`h
and bulk donsity. The oloctrical rosistance is not used, since il ig only where x are the coordinates of an observation and dx is the distance
availablo at 15 loealions. vector to a s£cond observation The estimated variogram V(|dx|)
As ompirical relalionship for the Kmiithauson tost site we obtain: is fitted within the method of least squares using the gaussian 0®•., . . , , .\,9®
10Sio4.eo = l.06.10-2cr -8.38.10-5t+ 1.57gb -6.86. model with
91 , :,- ~ 9+.',
This .olation is used io forocast the h ydthoontrirovoalumouofthoinlvesitigacledtes l siclo.onduclivity distribution for •c- .++ V(|d±|) = Oo.(i_e-|±12/#)+no.
- - r- r- r_ r- -
e`,O. ,0;[..],0- ,Oold ,Oi,bjr ,aolo- 10i[mj]OJ `oü h the anothenbove equations Oo is the sill, ^ the correlation length, andu8get. E 0m2 * . ,. .. .. _ ..`, . . t :- t . t - - - - -1-.. : ; O e „ + '
-``` , .:5mt}ariBör.,ri iho ht/draürc cohductiüiiv_estimstDn ..;3¢ain -süe
;= . - -, & . - ¥ ,-~-' L t - . , . ,-:.-i, , , 1 . . . 7 +.:-``-- . , J l . - -':t.-t. J - . ' 1 + + i . i - - , } - , l , . . , ,:--^--t-_qjr.`.=`- disiiibmon (blackj vs. u6aof cpT data wm emp-iricai n6hd.on (ed), •` tlie variogmms wBre computöd fo! a dx of lm and ln an gBiriuthal --* - (
int®rvaJ of 10 degroes with pi® slicos of 30 dogree3 width. Tho
01D rogu''9E.r®sp-Jhye' shown bolow lor elovationsvoly.tL``T-(.oTi/-^`J2Q[in tho middlo of layer9 D and_lü®[
EO, 8 , , 92,,T+- •`` -` e'0 5 |0 |$ 20 8'0 .5 00 138 1m
-'- :# gt :ä ,[ f] [f 1 [ il i ,_1: - J
p-Li i-`-`-L+' iii LH `1-e." =a ,,_u& 3!.,,T,_ :-#flg: - m IlT,{. ' \ J ,J , , + 5ao --.=, J •V aWll lth.oe tp®Crseto ssienten cKtelmudu tshthaluoose nrne.•gWsuolctasn eostfi maa tsopthaothiyadJmluyli cd ceonndsuec lCiviPtyT iiosi nsgu arnv e®mpyirical
t.'
\
i`` \
` felation fou"] by mumplo linoar rogrossion.
®ß - q -„®-,uymm'5l'm'
-'ö m • Tho heterogeneity deponding on depth and azimuth ischaJacterisodbyvariogramamlysis.
®.rL=,eo 01"2 0 15P®bL+i Upd#£ 0 ,¥, 6D OO,.O:d,„ m ®'_`--..a.`
• Tho analysis shows diff©rönt coiTelation propenies in the
Borehole data (807) artd bolonging CPT data used foJ multiplo regmsgion.
3D estimaled hydraulic conduclMty dis`ribution of th® tost gite