GB Poschmann,A. S.; Klassen, K. E.; *-) Klugman,M. A. s614 SLOPESTABILiTY STUDYOF THE SOUTHNATION RIVER AND PORTIONSOF THE OTTAWA RIVER
GB 448 .s634 'iliiil iltfiql[U [iryfitiil ilfiimlii' Ontario GeologicalSurvey MiscellaneousPaper Il2
SlopeStability Study of the SouthNation River and Portionsof the OttawaRiver
by A.S. Poschmann,K.E. Klassen, M.A. Klugman,and D. Goodings
A project funded by the South Nation River Conservation Authority, the Federal Depart- ment of Regional Economic Expansion, and the Ontario Ministry of Natural Resources.
1983
\ a\.'
Hon.Alan W. Pope Ministryof Minister Natural W.T Foster Resources DeputyMinister Ontario
South Nation R iver
ConservationAuthority eoMNR-OGS 1983 tssN0704-2752 Printedin Canada rsBN0-7743-8219-8
Publicationsof the Ontario Ministry of NaturalResources are available from the following sourcesOrders for publications should be accompanied by chequeor money order pay- ableto lhe Treasurerof Ontailo. Reports,maps, and price lists (personal shopping or mail order): PublicService Centre, Ministry of NaturalResources Room1640, Whitney Block, Queen's Park Toronto,Ontario M7A 1W3 Reportsand accompanying maps (personal shopping): OntarioGovernment Bookstore MainFloor,880 Bay Street Toronto,Ontario Reportsand accompanying maps (mail order or telephone orders): PublicationsServices Section, Ministry of GovernmentServices SthFloor,880 Bay Street Toronto,Ontario M7A 1NB Telephone(local calls), 965-6015 Toll-freelong distance, 1-800-268-7540 Toll-freefrom AreaCode 807, 0-ZENITH-67200
Thispublication can also be obtained from: OntarioMinistry of NaturalResources ConcessionRoad Kemptville j ontarioKoG 1J0 I Telephone613 - 258-3413 l l Thisproject was funded by the South Nation River Conservatton Authority, the Federal De- partmentof RegionalEconomic Expansion, and the Ontario Ministry of NaturalResources.
Everypossible ef{ort is madeto ensurethe accuracyof the informationcontained in thisre- port,but the Ministryof NaturalResources does notassume any liabilityfor errorsthat may occur.Source references are includedin the reportand usersmay wish to verifycritical in- formation.
Partsof this publicationmay be quotedif creditis given.lt is recommendedthat reference to thisreport be madein the following form: Poschmann,A,S., Klassen, K.E,, Klugman, M.A , andGoodings, D. 1983:SlopeStability of the SouthNation River and Portionsof the OttawaRiver; Ontario GeologicalSurvey, Miscellaneous Paper 112,20p Accompaniedby Geotechnical SeriesMaps 2486 and 2487,scale 1 :50 000.
CriticalReader: O.L White ScientificEditor: Guy Kendrick 1000-83-TwinOffset FOREWORD
SLOPESTABILITY STUDY OF THE SOUTH NATION RIVER AND PORTIONS OF THE OTTAWA RIVER
Thrsreport is the secondreport of its type to be publishedby the OntarioGeological Survey Preparedby the staffof the EasternRegion Otfice of the Ministryof NaturalRe- sources,the reportdraws attention to theexistence of potentiallyunstable slopes along the valleyof the SouthNation River and its severaltributary streams together with part of the OttawaRiver. The clay soilsforming these slopes owe theirorigin to materialdeposited in the watersof the ChamplainSea which covered the areaduring deglaciation about 13 000 yearsago. Theobjective of thisreport is notonly to alertthe generalpublic, planners, and the mu- nicipalitiesto the potentialhazards, but alsoto encouragedevelopers and landowners to arrangefor adequategeotechnical investigation of all landin the vicinityof riverbanks and slopeswell in advanceof anyconstruction or developmentthereon.
EG Pye Director Ont a ri o Geo log ic al Survey
lll CONTENTS
Introductron 1
Originand Characteristicsof theChamplain Sea Clays z Historyof Deposition Characteristicsof theChamolain Sea Clavs 3 SlopeFailure a FieldProgram 6 Airphotos 6 SlopeMeasurement 6 Analysis 6 SlopeClassr{icatron 8 SlopeStab rtyClasslfications . I S-mmarrT 1n .tn Acknowedgrg^14 Appendx 1 ...... 11 Co.nputerP'ogram ''11 Appendix2 12
ComputedFactors of Safetyfor SrrrueverlSitcq ...... 12 Beterences ..19
TABLE
', Table1--Some values for'Effective Angle of InternalFriction 0' 'Effective ', 'Pore Cohesionc' and Pressureru'obtained from site-soecific studres in the Ottawa and SouthNation River area
FIGURES
Figure1-The ChamplainSea and locationol thestudy area . .. z Fioure2a--Sheet Slide 3 Figure2b-Simple RotationalFailure j Frgure3a-Retrogressive Rotational Failure + Figure3b-RetrogressiveFlowslide ...... 5 Frgure4-Eanhf low. 5 FigureS--Showing the relationshipsbetween the slope rnclinations, theslope heights, and the Factorsof Safetyas computedfor this study 7 Figure6-Failed and unJailed slopes related to height,inclination, and the Factorsof Safety1 0 and 1.5 8
GEOTECHNICALSERIES MAPS (backpocket) Map2486 (coloured)-Slope Stability Study of theSouth Nation Fiver and Portionsof theOttawa River, Northern Sheet, Southern Ontano, scale 1:50 000, Map 2487(coloured)--Slope Stability Study of the SouthNation River and Portionsof theOttawa River, Southern Sheet, Southern Ontario, scale 1 :50 000 Conversion Factorsfor Measurementsin Ontario GeologicalSurvey Publications lfthe reader wishes to convert imperial units to Sl(metric) units or Sl units to imperialunits thefollowing multipliers should be used:
CONVERSION FROM SI TO IMPERIAL CONVERSION FROM IMPERIAL TO SI Sl Unit Multiplied by Gives lmperial Unit Multiplied by Gives
LENGTH lmm 0.03937 Inches inch 25.4 mm 1cm 0.39370 Inches inch 2.54 cm 1m 3.28084 feet toot 0.304I m 1m 0,049709 7 charns charn 201168 m 1km 0,621371 miles(statute) mile(statute) 1.609344 km AREA 1 cm2 01550 squareinches squarernch 6.4516 cm2 1m2 10.7639 squarefeet squarefoot 0.092903 04 1n2 1 km2 0 38610 squaremiles squaremIe 2 5899BB km2 lna 2,471054 acres 0.404685 6 ha VOLUME 1 cm3 0,06102 cubicinches 1 cubicinch 16.387064 cm3 1m3 35,3147 cubicfeet 1 cubicfoot 0,028316 85 ry13 1m3 1.3080 cubicyards 1 nrrhin rrard 0 764555 m3 CAPACITY 'I 1L 1 759755 pints prnt 0.568261 L 1L 0.879877 quarts. 1 nr 12rt 1j36522 ,1 I ^^il^^ L 0,219969 gailons I gdrur I 4.546090 MASS 1g 0.035273 96 ounces(avdp) ounce(avdp) 28 349523 S 1g 0.032150 75 ounces(troy) nr rnno /irntr\ 31.1034768 g 1kg 2.20462 pounds(avdp) pound(avdp) 0.45359237 kg 1 f(g 0.001102 3 tons(short) ton (short) 907.18474 kg 1t 1.1 02 31 1 tons(short) ton (short) 0.907184 74 t lKg 0.000984 21 tons(long) ton (long) 1016.0469088 kg '1 t 0.984206 5 tons(long) ton (long) 1.0160469088 t CONCENTRATION 1 g/t 0,029166 6 ounce(troy)/ 1 ounce(troy)/ 34.2857142 g/l ton(short) ton(short) 1 ^lt 0.583333 33 pennyweights/ 1 pennyweight/ 1,7142857 g^ ton(short) ton(short)
OTHERUSEFUL CONVERSION FACTORS 1 ounce (troy)/ton(short) 20.0 pennyweights/ton(short) 1 pennyweighVton(short) 0.05 ounce(troy)/ton (short)
NOTE-Conversionfactors which are in bold type are exact,The conversionfactors have beentaken fromor havebeen derived from factors given in the MetricPractice Guide for the Canadian Miningand MetallurgicalIndustries published by The MiningAssociation of Canadain coop- erationwith the CoalAssociation of Canada.
vl SlopeStability Study of the South Nation River and Portionsof the Ottawa River
by A.S.Poschmannl, K.E. Klassenz, M.A.Klugman3, and D. Goodingsa
measuredesigned. These measures should be based INTRODUCTION upon the geotechnicalinvestigations carried out priorto any developmentof a site,Property damage and incon- veniencecan then be reduced. The SouthNatlon River and the OttawaRiver are two of the largestnvers in southernOntario. The SouthNation It must be stressedthat this classilicationof the Riverdrains an areaof about3700 km2. The Ottawa River slopesis presentedas a guideline,and not as a site drainsan areaof about145000 km2, The SouthNation specilicvalue for engineering design. Riverdescends 84 m overa distanceof 177km fromits The methodsused rn this reportare a refinementof 'Slope sourceto its lunctionwith the OttawaRiver (Chapman thosedeveloped in the report StabilityStudy of the and Putnam1966) Extensivedeposits of glaciallyde- RegionalMunicipality of Ottawa-Carleton'(Klugman and rivedmarine clays that were latd down in the Champlain Chung1976) to classifyslopes in thesepostglacial ma- Seaoccur in the study area. rineclays. The study involved locating and mappingdif- Thetendency for riverbanks and slopescomposed ferenttypes of failuresthat occur in slopesin the Cham- of ChamplainSea clays in southeasternOntario to fail plainSea clays. The slope heights and inclinationswere and cause argeand smallscale landslides, is causing measuredat pointson the slopesconsidered to be repre- sentativeof a sectionof slope,These survey data were an increasrngamount of interestand concern,Costly 'Factor damageto bu ldingsand lossof lifemay result from con- usedto calculatethe of Safety',which is a numeri- structionon unstableclay slopes. Because of theseprob- cal representationof the stabilityof a slope.These Fac- lems,the Ontario M nistryof NaturalResources ts endea- tors of Safetywere used n the processof classifyingthe slnnes Fach r:lass rdent f'pcl nffcrc' ntr dplincs fOf voring to c assrfythe c ay slopes accordingto their J'vvvJ. detef- ^+^hiri+\, ^^^^ ^.\/arp.j geotechnicainvestigation neces- >tdulllty ll I d Yd> u, ltg uuvElEu uyhri.hc tl lc vlCh:rnnlai" lq,, rplql Sea. mrningthe amountof san to erSur€ the safe use of a s te The classiiicaton of the slopesIn th s sensrtrveclay is intendedto alertdevelopers and plannersto the need The s opesexam ned n th s rspsl arecontained in for determinrngthe geotechnca evauat on oi thestabt - the So,.rt.Natror' Rrver watersned and alongthe Ottawa rtyof a slopeat a soecrftc s te T^us -^stablesiopes can Rrverfrorr. Otta'^,a to T.eadwe Treadwellis locatedap- (rr be identi{iedand the necessarvremedtal or protectve prcxmate y 8 eastof the moutho{ the SouthNation Q tr.:-- q e' 2 JvYvvl!!qJYvvvvvv'rt|vv,nnn- ^is o.or r^lpnhv thc SOUthNa-
'Geotechncal Engrneer Eastern Region Ontario Ministry oi NaturaResources, Kemptvr le 2GeotechnicalEngineer, Eastern Region, Ontario Ministry oi NaturalResources, Kemptvr le 3RegionalMines Coordinator, Eastern Region, Ontario Ministry ol NaturalResources, Kemptville 4FieldAssistant attached to RegionalMines Coordinator's Office, Eastern Region, Ontario Minrstry of NaturalResources, Kemptville. Approvedfor publicationby the Chief, Engineerrngand TerrainGeology Section, Ontario Geological Survey,Toronto, 6 April1983. Thisreport is publishedby the permissionof E.G.Pye, Director, Ontario Geological Survey, Toronto. SlopeStability Study --. tionRiver Conservation Authority, the Ontario Ministry of redat theend of theglacial period (Kenney 196i NaturalResources, and the FederalDepartment of Eco- influxof freshwater from Lake Ojibway-Barlo!! p'c j':: nomicExpansion under the EasternOntario Subsidiary sivelydecreased the salinityof the regresstngse' :. Agreement. 10200 B P.,the Champlain Sea was sufficiently dra -:: fromsoutheastern Ontario for a fluvialregime at Bo,i.9e: Ontarioto become established (Gadd 1978a 1978b) Thesurficial geology o{ the area under study rn i- : ORIGIN AND reportwas included in the regionalstudy of Chapn-a- andPutnam (1966) and, in more detail, in maps prepare l CHARACTERISTICSOF THE by Gwynand Lohse(1973), Gwyn and Thibault (1975 Sharpe(1979), and Richard (1982a, 1982b, 1982c, anc CHAMPLAIN SEA CLAYS 1982d). TheChamplain Sea clays are highly variable in tex- HISTORY OF DEPOSITION tureand composition because of changes in environmen: duringthe transgression and regression ofthe sea, anc The sensitiveclays of southeasternOntario, which are thesubsequent fluvial reworking ofthe clays, commonlyknown as theChamplain Sea, or Ledaclays, Underlyingmuch of the study area, is a thindeposit weredeposited during the late stages of the Wisconsinan of rhythmicallystratif ied silt and silty clay, which is in con- glaciation.At thattime, the retreatof the Laurentideice tactwith glacial features left by the retreatingice sheet sheetenabled the Champlain Sea to invadethe St. Law- Franshamand Gadd (1977)proposed that this varved renceLowlands and OttawaVallev, and much of south- sequencerepresents material deposited in the trans- easternOntario, gressingsea in close proximity tothe glacier. The condi- The ChamplainSea began to transgressacross tionsunder which deposition occurred would thus be southeasternOntario sometime before 12 800 B.P. At that controlledby the large volume of meltwater coming from time,the landsurface was inundated as far as Clayton, the ice sheet;and the processof rhythmicdeposition Ontario(Gadd 1978a, 1978b). The sea continued migrat- wouldnot be imoeded. ingwestward to reacha limitwhich extends from west of Theinf lux of f resh water diminished with the retreat of Pembroke,to west of SmithsFalls, then south to theglacier. The clays deposited under the increasingly Brockvilleon the St. Lawrence River (Figure 1) Muchof salineconditions show a gradationfrom clearly varved theland surface was submerged to depthsup to 190m. fresh waterto massivemarine clays (Franshamand lsostaticrebound then began to progressmore quickly Gadd1977; Gadd 1978a, 1978b). thanthe oeneral worldwide rise in sealevel which occur- Themarine clays deposited in a deepsea environ- mentare typically dark grey, but light layering or black sulphurousmottled clay do sometimesoccur. A continuinguplift of the land surface resulted in the placementof shallow,pro-delta deposits over the top of the massiveclays Thesematerials are usuallylayered, redand grey, or lightand dark grey, and contain seams of silt,Beds with a highclay content are darkerred or LAKEOJIBWAY-BARLOW greythan the more clay deficient layers. Material depos- itedin moreshallow and less saline waters contain more pronouncedsilt and silty clay layers than material depos- itedin a deeosea environment. Sequencesdeposited in the regressingChamplain Seacontain reworked clay-sized material from areas that hadbeen uplifted and subjected to erosion.It isthis clay to whichthe redtint of the bedsis attributed(Johnston 1917)The red colour is particularlyevident in the mate- rialdeposited in the estuarine environment of theances- tralOttawa River. Inflow from Lake Ojibway-Barlow pro- videda largevolume of freshwater. This water eroded theclay deposits to the northwestand reworkedand de- positedthe material further to the east. A 2lo 4 m thicknessof sandoverlies the Champlain Seaclays. This fine-grained sand, believed to havebeen depositedby fluvialactivity after the withdrawalof the Figure 1-Dngram to show ChamplainSea, LakeOjib- sea,now covers large areas of southeasternOntario. In way-Bailow,and location of studyarea. somelocations, the contactbetween the clayand the sandis gradational. 2 Thethickness of the ChamplainSea deposits varies The ChamplainSea claysfrom variouslocattons ex- greatly,and is dependenton the bedrock topography hibithigh liquidity indices This index gives an indication and the amountof erosronsubsequent to deposition.At of the flocculated nature of the material.High siltcontent thewestern limit of theChamplain Sea, shoreline features willlower the indexand modifythe structurein thedepos- werenot well developed or ifthey did develop, have been erodedaway. In the naturaldepressions in the bedrock, considerablethicknesses of ChamplainSea clays still oc- cur.Near Arnprior, 91 5 m of claycan be foundat the site of a gravityclay fill dam (Wong et al 1975) at Waba Muchfurther east at Treadwell,a depthof 1047 m was STOPEFAILURE measured(Fransham, Gadd, and Carr 1976a, 1976b) Slopefarlure rn Champla n Seaclays produces easily rec- 'anrlfo.rc 'hat nnniz:hle r:an he sccnI clcarlvv,vqi rJ On aefial CHARACTERISTICSOF THE photographsThe stabrlllyof all slopesis dependenton CHAMPLAIN SEA CLAYS the geornetryof the s1ope,the physicalproperties of the malartel anmnnqrnn tha e ^nF enn tho nnro \l/ator nrae- The term clay,when used with referenceto the Cham- suresexisting within the material. Thus, slopes with a sim- plainSea clay, applies only to theparticle size of thesedi- ilargeometry can vary in stability.Thrs is dueto differ- mentand notto the composition.Even this usage of the 'clay' encesin stratigraphy,structure, and the seasonof the word can be a misnomerbecause the Champlain year Seasonally,variatrons occur because of thediffer- Seadeposits are highlyvariable. The moremassive de- encesin the amount of precipitationand the fluctuating positshave a claysize fraction as highas 80%,while the watertable, layeredmaterial in the shallowerdeposits can haveas lit- tle as 30% clay Siltand sandhorizons are quite common. Failurein theclays can take one of severalforms. A commonfailure type is the simple rotational slip of a seg- Theclay-sized fraction of the ChamplainSea clays is mentof slope.The curvature of theslip surface can vary composed of rock flour, Rock flour is rock material greatly. ground glacial to a fine consistencyby action.In the portion ChamplainSea clays, the rock flour is composed pre- Whenthe failure arc canbe drawnas a of a dominantlyof feldspar,quartz, and amphibolewith minor circlewith an almost infinite radius, the failure is called a illite, sheetslide (Figure 2a). When the curvature is morepro- amountsof clayminerals, these are usually chlorite, (Figure andvermiculite The percentage of theconstituent miner- nounced.it is knownas a simplerotational slip alsis highlyvariable, though quartz generally dominates. 2b) The Chamnla,n Sca c.lavsa.p strat fierl cleoOSilSwrth differencesrn physical propertres Doth latera ly andverti- callybecause of changes n the environmentof deposi- ,c tion.Extensive studres of the propen'esof the clay have been carriedout at site-specilrclocalitres These locali- ..t / tieshave been at the sltesof particularlynoteworthy land- slides,or at the sitesof largebridges and dams.No re- gionalstudies of the relativegeotechnical properties of the clayshave yet beenundertaken in Ontario. ."' / The mostimportant property common to the claysat /r' 'sensitivity' all theselocations has beenthe of the materi- ^.9/ / al.Sensitivity isthe ratio of the undisturbed strength of the ,""y a\"'/ / soil to the remoulded(disturbed) strength. The natural strength,which is lostwhen the soil is disturbed, is due to n&t"' / bondingand orientation of the clay particles, ./' / Thebonding in the clays is not fully understood; how- ever,several theories have been proposed.One theory, whichappears to havewide support,is thatthe clay in its \lnitial slop€ naturalstate, has particlescemented together in an open flocculatedstructure, rather like a houseof cards. The \t{ strengthof the clay in thisstate depends on the cement- ing and the degree of opennessin the structure,lf the clay materialis disturbedor remoulded,the flocculated structurebreaks, the particlesrealign, and the strength decreases.Weak or strongclays may have high or low sensitivities. Figurc 2a-Cross sectionof a sheetslide SlopeStabilitv Studv
moreclay (Figure4). Claypinnacles can oftenbe seenin of re- --u,C the debris of earthflows,but they are composed / mouldedclay squeezedbetween blocks of intactmateri- al. eao'q"\9!e99- Earthflowsterminate when the characterof the up- landsmaterial changes, or whena balanceis achieved betweenthe spoil materialand the backslope,or when the outletbecomes constricted. When an earthflowis held in check becauseof the build-upof materialsat itsoutlet, neither the slopenor the spoilcan be consideredstable. Removal of materialfrom the outletmay starta{resh the flow of spoil. In 1977 the SouthNation River was blockedwhen spoilfrom a slide in 1971moved again. The riverhad, Figure 2E-Cross sectionof a simplerotational shear. that had occurred over the 6-year period,eroded rnaterialfrom the outlet and allowedthe spoilto shift.This reblocked the outlet, As erosioncontinues, it is likelythat the processwill re- peat and retrogressiveflowslides leave Orter one smallrotational slip will initiatefailure of itself.Earthflows theland surface that last for thousands of s-c: ess . e segmentsof slope which can continue thumbprintson years, throughnumerous slides to form a reverse-sloped,ter racng eflectrn the slope (Figure 3a). This type of failureis Two othertypes of failurecommonly occur. One type termeda retrogressiverotational slide, is the erosionalslumping that occursat the toe of slopes by thef low of waterIn the adjacent A variationof the samekind of failureis the retrogres- due to erosioncaused stream.Such failurestend to be small because srveflowslrde. The slopesegments in the retrogresstve riveror effectof the wateraction is concentratedin rotatonal failure slip a shortdistance along the failure arc, the erosional areaof the immediateriver bank. These slopes and theslope segments in a retrogressiveflowsltde exhi- the limited and steep,often with overhanging vegetation. b t extremerotation. In largeretrogressive flowslides' it is areshort possble to see intactclay pinnaclesrising from the de- The secondfailure type occurs not in the clay itself, brrsThese pinnacles form as a resultof the rotation of the but in the fine sand and siltthat overlies the clay in many farledslope segments, and are composedof intactclay areas,This kind of failurehas beenreferred to by Mitchell (Fgure 3b) and Klugman (1979) as internalerosion. Like the rapidmass wasting process without a ro- 1f a failurein a slope developsand retrogresses earthflow, it is a What remainsis a gullywith nearvertical throughthe uplandwithout the rotationalsliding associ- tationalslip a lowgradient. Little spoil is leftin this resulting ated wrtha retrogressiverotational failure or a retrogres- sidesand gully, creek bed, becausethe watercontent in the s ve flowslide, that failure is called an earthflow or materialis such that the silt and sandf low as a slur- Earthflows are believedto be initiatedby the failureof a failed smaI segmentof slopewhich normally has a remoulded ry effecton the clay in the slope.The remouldedmaterial Instabiity in clay slopesis most often initiatedby wi I flow cause more of the slope to fail, and acttvate changesin the geometryof the slope profile.Erosional activityby natureor disturbanceby mancan oversteepen a slope,causing instability Even though the geometry of
Sliosurface
lT:?'""0"\
Figure3a- Crosssection of a retrogressiverotational shear \a=\-''Sliosurfaces 'ir:"*
Flemoulded clay
Figure3b-Cross sectionof a retrogressiveflowslide,
the slopemay be unstable,actual slope failure may not Lemieuxon the SouthNation River, when 36 ha of pas- occuruntil the pore water pressures and other conditions turelandfailed. or orocessesare conducive to failure. Bothlarge and smallfailures, which occur every Manyslope failures have occurred in the area of the year,can cause considerable local distress. The princi- SouthNation River watershed. These are usuallysmall ple concernsof thisstudy are to delineatethe areasof landslidesorfailures, measuring from a fewthousand cu- potentialfailure, and to recordpast failures. The respon- bic metresof materialup to manyhectares. Old scars in- sibleauthorities should ensure that any area slated for dicatethat many larger failures, 25 haor more,have oc- developmenthas been properlyassessed for safety curredin this basin. The most recent of these large slides againstpossible slope failures or landslides occurredin 1971,2 5 km upstreamfrom the village of
-^i Successiveslip surfqces \,1J a[['\]r\Jf lx \.,niti?,s,ope \)r' ilt',ttt\t.,' .,tt ,"^ r \t tl i=i=#i:>r))s)^'-'.. Remouldedclay
Figure tlCross secfionof an earthflow SlopeStability Study
FIELD Slopeswith profiles that showed variations in inclina- PROGRAM tionwith height were measured in segments to betterdel- ineatethe true slope, Survey points were taken wherever therewas a changein the height The field programwas startedin 1976 or inclinationof the and completedin slope.Profiles of thefailed surfaces of alltvpes land- 1980.All creeks and riverbanks in the South Nation River of basinwere slideswere surveyed, along with the profi16of theadJa- examined.Slope failures and landslidescars centslope, The adjacent profile were recordedwhere slope seryesto illustrate recognized,Large slope failures the probableslope conditions prior previouslymapped by the to the failureand is GeologicalSurvey of Canada usedto classify the slope in that sector. were,after field checking,incorporated into the maps of thispresent report (Fransham et a\.1976a, 1976b). Measurementswere particularly important on slopes >2 m inheight or with a gradegreater than 1 :4. The maxi- Thef ield work was carriedout bv canoeon the South Nation, mumerror in heightwas 1 m in slopesof 10m or more, Castor,and OttawaRivers. inis allowedeasy ac- anddue to the irregularities in cess to the riverbanks. Where thesurfaces, the maximum the volumeof waterwas errorin the angle of inclinationwas 2o. insufficientfor canoeing,as was the case on its tributar- ies,the examinationof the slopeswas carriedout on foot. Specialnote was taken of bedrockwhen it was pres- The locationsof the surveypoints and slide scars were entin slopes, and also of existingflood plains. Their pres- accuratelylocated on airphotooverlays during the exami- ence requiresconsideration in slopeclassification as nationof eachsite. bothconsiderably affect the stability of the slope.
AIRPHOTOS ANALYSIS
Theairphotos used in the f ield were 1971 photographs at Thestability classifications for slopesin ChamplainSea a scaleoI 1.17000. This scale proved large enough for claysare basedon the Factorsof Safetycalculated for efficient and accurate plotting of locations.All river banks eachslope. The Factor of Safetyis simply a numberrelat- wereexamined in stereopairs prior to enteringthe f ield. ingthe magnitude of theforces holding a slopetogether Themethod of interpretation to themagnitude of theforces that are seeking to levelit. "Air hasbeen described in the thesis, PhotoClassification and Glossarv'Lawrenceof Land- Theoretically,a Factor of Safetygreater than 1 .0 indicates slide Problemsin the Ottawaand St. thata slopeis heldtogether by forceslarger than those Lowlands"(Poschmann 1978). Pertinent features and seekingto failit andthe slope is stable. Conversely, if the areasof possibleinterest were noted on ihe overlays that Factorof Safetyis lessthan 1 0, the slopeis unstable, wereattached to alternatephotographs, In thefield, the andthe forces seeking to fail the slope are larger than the overlayswere used to recordthe locationsof the slope forcesresisting them, and failure occurs. surveysites along with the data collected in thefield, as A Factorof Safetyequal to 1.0is the critical condition well as otherfeatures such as landslidescars. These in the idealcase wherethe soil characteristicsand datawere then transposed from the overlays to NTStopo- strengthparameters, and the height, inclination, and sat- graphicmaps at a scaleof 1:50000. The survey points urationof theslope are accurately known. Given the con- were numberedand the differentfailure types appro- ditions,it is possibleto constructa graph, shown in Fig- priatelyindicated in thefollowing categories; earthflows, ure5, illustratingthe relationshipbetween slope height, retrogressiveflowslides and retrogressiverotational inclination,and the Factor of Safety. slides,rotational slides, sheetslides, failing slopes, and internalerosion features. Nevertheless,it has been found in these clays, that a factorof 1.5 ratherthan 1 .0, is the critical Factor of Safety thatmust be used.This is welldemonstrated in Figure 6, SLOPEMEASUREMENT whichis a plotof thefailed and unfailed slopes related to height,inclination, and the Factors of Safety 1.0 and 1.5. An examinationof the graph Inorder to determinethe particular showsthere are some stabilityof a slope,it is slopesthat have failed with Factors greater necessaryto obtaininformation its profile. of Safety than on Thiswas 1.5.They represent only 6% of the donein the field using a metre surveyedslopes, and stickand clinometer. aredue to factors as yet unidentif ied. Theprofile of a portionof a riverbank was measured Tocalculate the Factor of Safety,the geometry at a pointin thatsegment considered to be representa- ofthe slope,the groundwaterconditions, and the strength tiveof the whole.This point is referredto as a survey of point, point, thesoil need to be known.The slope profile and ground- At eachsurvey the heightof the bankwas water (pore pressure) measured conditions,ru water aremeasured bytraversing the slope with a metrestick, and inthe f ield. The parameters (effective theinclination was parallel strength 0' angleof takenwith a clinometerheld to internalfriction) and (effective theslope. These measurements profile c' cohesion)are deter- illustratethe slope minedby laboratory testing. onlyon the day the surveywas taken. Hence, they are timedependent. In addition,because the informationis Thefield program for thisstudy involved measure- usedto representconditions on a lengthof theslope, the mentof the slopeprofiles only. Values tor ru,6' , and c' computeddata cannot be considered to besite specific. havebeen assumed. These assumed values are based 6 22
2.O
F l.!l lr a lr p r .8
I 14 16 n 22 24 HEIGHTOF SLOPE(METRES)
Figurei-Diagram showingthe relationshipsbetween the slope inclinations, the slope heights,and theFactors of Safetyas computedfor a studyin the Ottawaarea (Klugmanand Chung 1976).
As a precautionagainst over-simplication, a range of principallyon pub icationsby personnelof the National SafetyFactors for each conditionwas alsocalculated for ResearchCouncil and therrassociated workers, trom O'valuesof 30"and 35" by Klugmanand Chung(1976). soilsreports of theOntario Ministry of Transportationand Theirstudy found that these 2 conditionsdid not signifi- Communications,from consultant'sreports throughout ca^t,vafrect tre seore^ts of tneclassification. the area,from Universitytheses, and limitedtesting by Two cond,t,on!,r. no,rd herein the analysis.The D.J Goodingsas a preliminarycorrelation with published frrst condrtron occurs when bedrock rs encountered at the data. footof a slope Whenbedrock was found, it wasfollowed Slopeswere assumed to be hydrostaticallysaturat- up Intothe bankas faras possible.Bedrock can act in a ed. Thatis a situationwhere the top of the groundwater slopein 1 of 2 ways: tablecoincides with the landsurface and thereis no mo- 1, by formingan impermeablelayer, which will keep tion in the fluid Thisis a typicalcondition in the spring the watertablehigh in a clay slopeand increasethe when most landslidesoccur. The parametersc' and 0' chancesof failureby helprngto saturatethat slope were assignedthe values10 kN/mzand 33" respectively. and by acting as a slip surfacefor the clay to fail Table1 showsthat these values are realisticfor use in the along,or calculationsused to categorizethe clay slopes in the 2. by composingmost of the slope and reinforcing semi-quantitativeclassifications used in this report. thethin clay mantleon top Unfailed Slope a Failed Slope 55 6-l- a-a a a Where values for unfailed aa a and failed slopes coincide a a 50 a a AOA Five classified slooes - - aO a a\ a a I a a - ll5 o - aa ao a o- A a a a a a a a aa I AI t .\- a a d4 o I a .F - a a u 7$' a a - - t -a 4t A A ^x\ ax a a g ^ a- o$, I al - - A "bO ^oA Aa ot ag8 t - a- a - 30 aa$ A -a aoo a aoo t t a aal - s a Oa H a A i\i ^a\ aa 9 d.s c)25 A|\ ad4 ^44 a a a6 Htr a lr ,^ lo o - ^ a aa a I "^+ a 720 a A a4 I a F K 215 od = A C) o -10z A
46 10 HEIGHTOF SLOPE IMETRESI Figure 6-Diagram showing the relationshipsof failed and unfailed slopes in the study area to height, inclination,and the Factorsof Safetvof 1.0and 1.5.
Ali calculationson such slopeswere conservative, assumingfrom the lastpoint of outcropthat the remaining SLOPECLASSIFICATION part of the slopewas not defendedby bedrock.Slopes totallycomposed of rockare notedas suchon the maps. Theslopes have been grouped into 6 classesbased on The secondcondition concerns the existenceof 2 thecomputed Factors of Safety. The specif ic values used slopes,the riverbank and an upperslope, separated by in the classificationare presentedonly as a guideto a terraceor floodplain, When the riverbank was low,and slopeconditions, not as a firmbasis for engineering de- an examinationof the airohotos revealed that the signor development. Under all circumstances, site-spec- floodplalnwas inundatedduring spring runoff, the upper ific studies and/or inspections should be carried out at all slopewas measuredand a Factorof Safetyestablished. sitesbefore any planning or development isundertaken. In thiscase the upperslope represents the worstslope given conditions,saturated but notsubmerged. When the river A dualclassif ication is foreach of the 6 classes high the terrace is not flooded every of slooe.One is a numericalvalue based on the calcu- banks are and parallel spring,both slopes were measured and the lowestFactor latedFactors of Safetyand the second is a corre- of Saietywas usedto classifythe slope, spondingverbal description for each class, lt isstressed that the classification system is generalized.This
.EFFECTIVE ', .EFFECTIVE 'AND,PORE SOMEVALUES FOR ANGLEOF INTERNAL FRICTION E, COHESIONc, PRESSUREr"'OBTAINED FROM SITE-SPECIFIC STUDIES lN THEOTTAWA AND SOUTH NATION RIVER AREA.
CriticalStrength Parameters Slope c'(kN/m' ) 0'(deg) tu Remarks Source
_ roncex LEMIEUX B2 39" 0.62 Accr rmod h,/alra ^^, '-^; h, '^ '^. i -. - SouthNation S rde 90 36' 060 nJ>ur rcv I yu uJra. ! Ecen Fetcher, saturation. lv'lic re 1971 . Cumberland 25" 0,62 Accrrmod h\/r1.a hasbeen done to take ntoaccount the Jact that c' and0' The necessaryInvestment to prepareand stabilizethe areaveraged values and notentirely accurate numerical sitewill be greatand probablywould make normal devel- qtronntn:t: Iranroaant2t evr eovl nnc n{ c,npci{,c locafinn opmentuneconomrcal. 1.2-15 Detailedgeotechnical investigation necessary, withconcomitant remedial works. This class, SLOPESTABILITY CLASSIFICATIONS underundisturbed conditions, is considered (afterKlugman and Chung1976) marginal.Stabilization works or restrictive physicalconditions would be necessary. Factorof Gu delines Theirtype and extentwould depend on the Safety typeof development <0,8 Unsuitablefor construction, or willrequire extreme 1 5-20 Routinegeotechnical investigation necessary. remediaimeasures in orderto safelyutilize Develooerwou d haveto know soil condi- the site.These measures would need to be trons Stabizai on workswould dependon basedupon extensive detailed geotechnlcal Iypeard srzeo' p annedstructures, studies.The proportionof necessaryinvest- 2 0-25 Routne rnspectronnecessary to determjnethe ment to make the propertyusable for con- need and extentof geotechnicalinvestiga- structionprobably would out-weigh the cost tion. of the completedstructures, lt is thereforenot economicallyfeasible. >2.5 Shouldbe inspectedbut no remedialaction likely to be requrred This class also includes 0 8-1.2 Will require extensiveremedial measures as slopesthat were nspected,but becauseo1 dictated by detailed geotechnicalstudies, their nature,no detailedrecordings were oeemeonecessary SlopeStability Study Safetythan the watercourses in the northernpart of the SUMMARY SouthNation River watershed. lt shouldbe stressedthat thereare exceptions in eachcase. As indicatedon the northernand southernmap sheets, the SouthNation River and the oortionof the OttawaRiver thatwas studiedillustrate variable slope characteristics. Areas with high Factorof Safetyvalues can be directly ACKNOWLEDGMENTS adjacentto locationswith lowerFactors of Safety,Differ- ent Factorsof Safetyalso occur on oppositebanks of the river. Thewriters would like to acknowledgethe assistance and The portionof the SouthNation River between Bear invaluableadvice during the courseof thisstudy and the preparation Brookand the CastorRiver is exceptionallyprone to land- of the manuscriptof thefollowing: staff mem- sliding Examplesof areaswith low Factorsof Safetycan bers of the SouthNation Conservation Authority; Profes- be found aroundFournier. St-Bernadin. and a section sorR.J. Mitchell, Queen's University; Dr N R.Gadd, Geo- alongthe OttawaRiver northwest of Orleans.Areas with logicalSurvey of Canada;and associatesin the Ontario high Factorof Safetyvalues are found in the vicinityof Ministryof NaturalResources and the OntarioMinistry of Winchesterand Spencerville.In general,rivers and Transportationand Communications, streams south of Chestervillehave hioher Factorsof 10 APPENDIX 1 COMPUTERPROGRAM Card 9-1645 Thecomputer program used for calculating the factors of Card1O - 1O -for constantr, safetywas developedat the NationalResearch Council Cardl1-062 -(,t by J. G Arseneault(1967) and was adaptedfor the first Card12 - 33 -4' (indegrees) report(Klugman and Chung 1976)by ProfessorR, J. Card13 - 273A ---othertrial values of 0' formini- Mitchellof Queens University,Kingston, Ontario, The mumFS {or tractors - -X P'-Y'*'nrooramso,vcs of Safetvhv an iterative Card14 X.Sr co-ordinatesfor search area processusing the Standard Blshop's equation for analys- forcrit cai centres. ingslopes. Card15 - Y.Y, -Y co-ordinatesfor search area forcr t ca1centres. Each slope was approxmated wrth three or more line Card16-XY X Y co-ordinatesof chosenfail- segmentsresolved into a co-ordrnatesystem. The toe of urepornt tho clnno \^/2< .hneon i 2c tha nnrnt thrnr rnh 117[i6h all alin rr re orvye vvqr errvJe ur !riu Pv' r rrilvuvrr vvrilull all )llP Card17 - Blank-termrnates readtnos and directs circlesin the failng slope woud pass.The Factorof progr3;'lo nextsiope number Safetywas calculatedby drvrdrngeach slip circleinto 100equal width slices through the slopeover which the On thebasis of thegiven input data, t is possibleto forcesare calculated.One hundredsuch circles,each show the relationshipbetween slope nc inations with a centrepoint ocated nsrdea designatedsearch and slope heightsto thecalculated Factor of Safety.The plot area,are solved to {rndthe minimum factor of safetvand shown in Figure canoffer an approximateguide thecritical centre, 5, fordetermin- ingthe Factor of Safetyof simpleslopes in the South Na- tionRiver watershed. The slopeswere assumedhomogeneous in soil and groundwater conditions. Given input data used were: Eachsite surveyed in the SouthNat on Riverwatershed rs c' -effective cohesionin kN/m2: 10kN/m2 shownon theaccompanying maps The have 0' ---effectiveangle of internalfriction in degrees sites been - ?Qo assigneda symboland a sitenumber Symbols without numbersare locationsof fai places, -unit weightof soilin kN/me : 1645 kN/m3 slope uresonly. In it 1 was notoossrble to tare reaongs ru -pore pressureratio : 0.62 at thesefailures or al- ternalivelyat tne d screto. of tre seniorauthor, mea- surementswere deemed unnecessarv. Theinput data cards we'e arrangeo as {ot ows Card 1-04 -s1openumber Appendix2 grvesthe computedFactors for Card 2 - 03 -number of I nesegments of of Safety all thesrrveyed srtes. t must slope(N) be stressedthat the computed Factorso'Safety are based profilemeasured Card 3 - x y -co-ordinatesof nodesof ine on a at a pointon thesloile and illustratethe Card 4 - x y -segments Inconsecut ve order slopeconditions only at thetime it was surveyed.The Factors Card 5-xy -(toamaxrmumof20l of Safetyare time dependentvalues Card 6-xy that shouldnot be used for detailed sitedesign, The Factors presented Card 7 - 1 00 -10-FS andc' of Safetyare solelyas a guideto furtherwork. Card 8 - 1O -constant,other than 10 means vanaole 11 SlopeStabilitr/Study APPENDTX2 COMPUTED FACTORSOF SAFETYFOR SURVEYEDSITES IN THE AREA OF THE SOUTH NATION RIVER WATERSHEDAND THE OTTAWA RIVER, FROM TREADWELL TO OTTAWA. Site Site Site Site Site No. No. FS No. No. No. >2 50 36 2.50 71 2.20 tuo 139 141 1.10 2 182 37 I4C 72 LOU 107 1.38 t4z 096 3 | .ov 3B 1.58 73 1.57 108 | .JZ 143 1.25 ,i 136 39 250 74 131 109 1.45 144 1.50 5 140 40 | .zJ 75 094 110 180 i45 0.77 6 148 A1 240 76 I.JJ 111 LJC t40 1.05 7 tca 42 1.12 77 098 112 1.64 147 0.97 B too 43 .34 7B I .JJ 113 1.29 148 1.05 9 2.00 187 79 1.55 114 1.38 149 0,97 10 t.J I 0.78 BO 1.58 115 1.15 150 | .zz 'I l 104 46 >2.50 B1 | .23 rlo 1.60 151 | .aa 1,2 080 240 82 LC4 117 tJo tcz 0,96 '1 13 100 48 187 83 | .za 18 120 tcJ 1.31 1tr4 1A Bedrock 49 142 B4 toz 119 1.92 106 15 1.50 50 tlY 85 185 120 1.71 tcc 159 16 230 ct | .oo B6 1.98 121 | .cJ 156 096 17 084 52 1.43 87 140 tzl 139 157 1.50 to 220 53 1.78 88 1 ta lzJ tJc 158 192 IV >2 50 1.42 89 1.42 lzc 135 159 1.43 1 Atr 20 >2.50 55 1.39 90 174 tzc 1.60 160 21 1.20 56 1.39 91 1.42 tzo LO/ tol 130 22 140 57 1.39 92 tz4 127 204 toz 165 23 087 5B 131 93 1.39 128 1.18 toJ 1.35 240 59 148 94 148 129 1.BB 164 1.50 25 | .ato 60 149 95 140 IJU 1,18 165 1.80 I Atr 26 2.38 ol 1.44 96 t3J 131 too 1.30 27 190 62 1.49 97 IJZ 1.28 to/ 1.69 28 085 63 121 9B LCJ IJJ 1.16 168 2.04 29 2.40 64 | .zo 99 LJ3 tJ+ 150 169 1.65 30 >2.50 65 130 100 |.32 tJc 1.40 170 1.51 31 098 66 140 101 | /3 136 1.03 171 0.92 32 159 67 176 102 207 137 1.19 172 090 33 LdJ 68 1.60 103 1.03 138 085 173 156 J+ 170 69 150 104 200 IJY 124 174 139 35 186 70 1.40 105 128 1AA 131 t/3 1.42 L2 APPENDIX2 - Continued Site Site Site Site Site No. No. No. No, No, 176 t33 214 | .cz 252 tcJ 290 >2 5A 328 2.29 177 127 zt3 234 253 236 291 110 329 1.25 '>2 178 189 zto 1.82 254 I./O 292 5A 330 1.77 179 0 81 1.60 255 | .zo 293 z t3 331 >2.50 180 .J 218 244 256 160 294 f,3 332 >2.50 '1 181 130 219 r.cc 257 .11 295 242 333 LJ4 182 z3 220 1.95 258 tJo 296 o4 334 1.49 183 JU 1.54 259 090 297 a 71 335 1.94 I /a 184 tlc 222 206 260 1 1Q 298 336 2.42 Iu3 223 >2 50 zot rJo 299 075 337 233 t ato i.cc 262 202 300 076 338 1.70 187 OBB 225 167 263 to+ 301 339 2.45 1BB 085 226 123 264 164 302 092 340 t. to 189 071 227 160 265 t.t3 303 a/ 341 220 190 >2 50 228 | .ctJ 266 137 304 097 J+l | .oJ tY I 235 229 1.48 267 1 15 305 150 343 1.67 192 217 230 2.03 268 137 306 i43 344 151 193 235 ZJI 1.47 269 1.20 307 087 345 193 194 >2 50 232 1.50 270 210 308 177 346 1.86 tva 202 233 >2.50 271 1.70 309 080 347 183 I YC, >2 50 234 2.22 272 171 310 143 348 1.28 197 1.44 235 1 10 273 t.ci Jil 124 349 I .JU 198 >2.50 236 2.25 274 1.34 Jtz 210 350 1.49 199 >2 50 237 2.40 275 l.co JJ 150 J3 l 159 200 | .J / 238 2.45 276 LO / 314 1 16 352 | .ttJ 201 1.34 239 1.40 277 LZJ 315 LZI 3s3 1.34 202 126 240 210 278 081 Jto 1.24 354 >2.50 203 1BB 241 1.73 279 1.44 317 108 355 | .Jt' 204 242 | .26 280 | .26 Jtb 1.57 356 1.43 205 220 243 127 281 t. tJ 319 2.19 357 t/3 206 IJJ tv3 282 z. to 320 108 358 1.59 I 1r' 207 >2 50 z+a 195 283 208 5Z 359 | .J4 I ql 208 248 246 284 >2 50 322 080 360 | .JO 209 243 210 285 323 203 JOI 239 ' 210 lo 248 34 266 .tY 324 :' 362 1.61 211 170 249 o3 2E7 aa 32. 363 068 212 172 254 245 288 t: 32e 364 234 213 lo 251 rJc 289 c 32- 365 l .3J 13 SlopeStability Study APPENDIX2 - Continued Site Site Site Site Site No. No, No. No. No. 366 179 404 1.50 442 200 480 a 609 367 184 1.78 443 LOJ 481 a otu 368 160 406 | .u:) 115 482 a 611 369 roo 407 112 445 2.43 483 otz 370 174 408 1.49 446 | .oJ 484 otJ J/ 159 409 184 447 142 485 a ot4 ( 372 1.73 410 1.68 448 I .JJ 486 otc 373 a All toz 449 IJJ 487 t./J oto 176 qtl 186 450 131 488 2.30 ot/ 375 l:rc 413 | .oz 183 489 230 otb 376 2.00 A1A 1.58 452 |.zJ 490 1.65 619 A1q 377 140 1.57 I .YJ 620 378 1.95 4to 1.CZ 454 1.88 ozl 379 2.07 417 A 089 622 380 177 418 200 / tra 235 623 381 1.59 419 202 457 083 586 184 624 382 (A 420 a 1.07 587 1.49 625 383 1.24 +11 134 459 2.45 5BB 1.50 626 2aA 1.43 422 1.69 460 145 589 1.40 627 to/ 385 159 423 1.27 +ol ( 590 082 628 t.co 386 tc3 424 462 130 591 1.03 629 1 1B 387 140 425 2.40 463 1.50 592 630 0 3BB z to 426 @ 464 128 593 LJC oJl 143 389 1.98 427 1.40 465 1.40 594 1.26 632 0.99 390 1.50 428 098 466 1.51 595 1 15 633 1.00 '1 391 208 429 1.81 467 .15 596 1.10 634 117 392 207 430 088 468 1.15 597 0.71 635 107 393 1.95 431 z ta 469 096 598 082 636 171 394 2.03 432 157 470 2.23 599 165 637 |.zo 395 1.85 165 471 226 600 089 638 234 396 189 434 I.JJ 472 224 bul 0.76 639 134 397 I trA 083 473 z.lJ 602 1.72 640 IJY 398 436 108 474 | .z+ 603 1.17 641 225 399 1.59 437 177 475 1.71 604 1.81 642 122 400 LOO 438 1.68 476 1.72 605 0.83 643 135 401 109 439 1 18 477 1.71 606 1.30 644 LJO 402 208 440 1 18 478 1.67 607 @ 645 l al 443 t./o AA1 |.JZ 479 w 608 646 I /J t4 APPENDIX2 - Continued Site Site Site Site Site No. No. No. No. No. 647 133 685 225 723 a /o l 086 799 0.81 648 149 686 a 724 2.35 762 149 800 131 649 tov 687 lvJ 725 a 763 068 801 079 650 191 688 0 726 LOV 764 067 802 152 ocl 0 689 170 727 086 765 803 120 652 129 690 208 728 086 766 079 804 090 653 r30 691 a 729 2.52 767 075 805 098 654 128 692 tJz 730 170 768 075 806 0.81 655 r38 693 198 731 LCO 769 075 807 096 ( 656 JI 694 732 | .cz 770 0 BOB 1.08 657 191 695 2.42 733 a 771 080 809 0.78 658 125 696 186 734 1.88 772 089 810 1.20 659 182 697 1.98 735 1.03 773 055 811 1.15 660 t3v 698 LJI 736 | .cJ 774 IJJ 6Z 0.88 ool 150 699 1.51 737 2.10 775 a dtJ a 662 t al 700 208 738 1.29 776 1 16 814 117 663 1 A1 701 228 739 1.20 777 087 815 138 664 | .JV 702 740 230 778 120 dro 1.18 '1 665 145 703 atl 34 779 a 817 0.90 666 1.73 704 170 742 1.16 780 t3/ 818 1.15 667 t./3 705 ( 743 1.24 781 a 819 LUC 668 205 706 z al 744 1 19 782 a. | | 820 A 669 1.43 707 z.a I 745 1.42 783 | .za 821 2.45 670 l1+ 708 a 746 a 784 | .JC 822 1.37 o/ | 1.13 709 | .oo 0.91 785 2.04 823 |.JZ 672 1.39 710 a 748 093 786 w 824 156 673 2.09 711 @ 749 1.37 787 082 825 1.24 674 1.83 712 1.45 750 2.42 788 1 14 826 | .za 675 a 713 | .JZ 751 1 A^ 789 092 827 100 676 1.07 714 752 116 790 142 B28 1.31 677 0 715 zc 753 0 791 110 829 1 19 678 1.42 /o 143 /44 11 792 0 830 1.28 679 198 717 755 793 062 831 1 AA 680 136 7t8 095 756 JJ 794 al 832 108 795 681 209 IJ Uf, 757 15C 07c 833 a 682 192 720 154 758 209 796 066 834 L04 --t - 683 0 721 0 759 c !1 835 0.86 684 oo 722 106 760 798 OBE 836 1.79 15 SlopeStnbility Study APPENDIX2 - Continued Site Site Site Site Site No. No. No. No. No. 837 103 875 2.14 913 0.84 951 A 989 'a_ 838 052 876 914 1.07 952 990 ' 839 101 877 ( 915 | .24 953 i/b 991 :- 8,10 079 B7B 1.95 916 1.29 954 ( 992 8,11 083 879 155 917 955 1.04 993 .. 842 a BBO 1.40 918 149 956 0.77 994 i i: a/ 2 1.78 BB1 1.31 919 957 $ 995 1': 814 a BB2 LU3 920 a 958 0.98 996 134 ( a/ | .Jv BB3 1.17 921 a 959 1.18 997 224 Q/A a BB4 1.19 922 a 960 | .cJ 998 11: 847 1.58 BB5 |.21 923 087 961 1,00 999 1 9"' aAa 130 BB6 1.31 924 1.02 962 0.55 1000 ryu 849 a BB7 I,UJ 925 a 963 a 1001 lcu 850 119 888 201 926 1.24 964 079 1002 851 116 889 tf,J 927 083 965 1.10 1003 07c 852 a 890 I lo 928 078 966 | .JO 1004 853 109 891 i .oo 929 1.24 967 1.90 1005 090 854 |.zv 892 LCO 930 1.16 968 180 1006 130 855 893 1.27 YJI a 969 140 1007 080 '1 856 1.89 894 2.29 932 a 970 30 1008 110 857 1.30 89s 1.02 933 1.31 971 1,30 1009 050 B5B 093 896 175 934 ( 972 1010 110 859 a 897 101 935 a 973 100 1011 110 860 121 898 1.74 936 974 0.70 1012 i40 861 1 15 899 1.24 937 ( 975 a 1013 070 862 109 900 084 938 976 130 1014 090 863 184 901 a 939 129 977 080 1015 130 864 154 902 095 940 097 978 070 1016 110 865 149 903 a 941 0.90 979 1.70 1017 080 866 o4 904 086 942 ( 980 080 1018 080 867 a 905 a 943 120 981 1019 150 B6B tto 906 0.70 944 097 s82 1020 170 869 IJU 907 a 945 120 983 0.70 1021 870 a 908 073 946 133 984 070 1022 6l 197 909 061 947 tJc 98s 070 1023 090 872 | .oo 910 0.82 948 1.50 986 130 1024 0.90 873 167 911 a 949 1.11 987 110 1025 100 614 n Jlz 084 950 a 988 150 1026 2ta 16 APPENDIX2 - Continued Site Site Site Site No. No. FS No. No. 1027 iB0 1063 2.00-2,50 1099 140 tJc 2.30 1028 130 1064 Bedrock 1100 140 tJo 2,30 1029 0 1065 a 1101 140 1137 2.10 1030 0 1066 2.10 1102 140 1138 2.10 1031 090 1067 0.90 1103 1139 0.90 1032 070 1068 Bedrock 230 1140 1.20 1033 I 10 1069 1.60 1105 150 1141 1.00 1034 190 1070 0.80 1106 070 1142 0.80 1035 1 10 1071 1.20 1107 080 i 143 1.90 1036 r40 1072 1,60 1108 140 11AA 2.45 1037 110 1073 Bedrock 1109 130 r4c 2.07 1038 Bedroc k 1074 Bedrock 1110 190 t+o 1.75 'I 1039 1075 111 120 1147 1040 1076 130 1112 230 1148 208 1041 240 1077 1.10 II IJ 1.70 t4v @ 1114 1042 130 1078 190 1.40 1150 | .12 1043 1 10 1079 0,90 1115 a 1151 200 1044 1080 1,20 ttto 1.70 1t3Z 2,15 1045 1081 1117 0.80 1 l3J 1,22 '1046 1082 250 1118 230 1 lc.+ 230 1047 1083 1119 230 1155 097 1048 1084 1120 0 1156 1.78 1049 1.70 1085 v 1121 080 1157 1.46 1050 1.60 1086 1158 1.78 1051 1.20 1087 1123 YU 1r59 1.71 1052 160 1OBB 1124 0 1160 t.to 1053 1 10 1089 1125 JU 1161 |.zc 1054 250 1090 090 1.,26 230 taz 160 ''27 1055 200 1091 090 JU roJ 2.18 1056 120 r 092 za JU og 1.70 1057 170 UYJ .J 0 r of 1.70 .l .c 1058 Bedrock 1094 JU 0 too z. t6 1059 Bedrock 1095 IJU J aiu 1167 160 1060 a 1096 J' c 1061 0 1097 JJ 0 1062 a 1098 1'34 234 17 REFERENCES GolderAssociates 1974a:SubsurfaceInvestigations proposed South_EastCity, Townshipof Gloucester;Unpublished report, Volume 3, ReportNumbe r 73908, Z2p. Arseneault,J.G. 1974b:Slope Stability Study 1967:A Programfor SolvingSlope Stability problems; Division of QueenswoodHeights, Gloucester Township, BuildingResearch, National Research Council of Canada. Ontario;Unpublished report, Report Number ComputerProgram Number 27, Ottawa, 2Op. 742062. Chapman,1.J., and Putnam, D.F. Gwyn,Q.H.J., and Lohse, n. 1973: 1966:The Physiographyof SouthernOntario, Universitv QuaternaryGeology o{ the AlexandriaArea, Southern On_ of To_ preliminary rontoPress, 2nd Edition,386p. tario;Ontario Divrsion of Mines, Map p.906, GeologicalSeries, scale 1:S0 000 Geologyi973. Eden,W.J,, Fletcher, E.B., and Mitchell, R,J Gwyn, 1971:South Nation River Landslide;Canadian Geotechnical Q.H.J.,and Thibautt, J 1975: Journal,Volume 8, Number3, p.446-451. QuaternaryGeology of the Hawkesbury-LachuteArea, SouthernOntarrot Ontario Division of Mines,preliminary Eden,W.J., and Jarrett, P.M. Map P.1010,Geotogicat Seres. scale 1:50OO0. 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Crossingof the South Natjon River and BoundaryRoad 1961:The Champlain Sea and itsSediments; p.97-108 rnSoils of nearVillage of Lemieux, Ontario;Unpublished report, File Canada,edrted by R.F.Legget, Special publication Num_ Number3305-5, GEOCRES Number 31 G-3. ber3, RoyalSociety of Canada 229p Fransham,P.B., and Gadd, N.R. Kenney,T,C. 1977:Geological and Geomorphological Controlsof Landslides 1964:Sea-Level Movements and the GeologicHistories of the in OttawaValley, Ontario; CanadianGeotechntcal Journal, Post-GlacialMarine Soils at Boston,Nicolet, Ottawa, and Volume14, Number4, p.531-539 Oslo;Geotechnrque, Volume 14, p.203-227. Fransham,P B , Gadd,N.R., and Carr. P.A. 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Sectionin EngineeringProblems in MarineClay, Geotech- 1982cSL:dcai Geology, Winchester, Ontario; Geological Sur- nicalSeminar, Arnprior Generating Station, June 13 and veyof Canada, Map 1491A, Scale 1 :50 000. 14,1975 (lnternal Report), Acres Consulting Services Lim- ited,Niagara Falls. 1982oSudroal Geology, Morrisburg, Ontario-New York; Geo- ogrcaSurvey of Canada,Map 14934,scale 1 :50 000. 20 ONTARIO GEOLOGICAL SURVEY MISCELLANEOUSPAPER 11.2 GeotechnicalSeries MaPs Map2486 (coloured)- SlopeStability Study of the South Nation River and Portionsofthe ottawa -i"EJ;[i"#rtheet, Southernontar o Map 2487 (c o Io u red )- 3:T: .'J1? i[I 8\Y:il;'J[: :3:'i' H,'"T,[:i'rT,ln ",.o n ta r o Scale1:50 000.