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Retrogressive slope failures at beaver creek, south of Saskatoon, Saskatchewan, Canada
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detailed st~y of ghructural weaknesses. The remalts were subsequently used to amaly~ different mo~es of possible failure af the rock mass. The info~ion obtained is being used in redesignim~ the Copper Mountain open pit, Quebec. 785172 T ~ N T AND MAI~IRNANCE OF ROCK SLOPES ON TRANSP~ION ROUTES Peckov~, F L; Kerr, J W G Can Geotech J~ VI4, N ~ NOv 197~, I~237-507 785173 GEGLOGICAL AND GEGMORFHOLOGICAL CON~RGLS OF LANDSLIDES IN OITAWA V~TTEy, O~TARIO Franaham~ P B; Gadd, N R Can Geotech J, VI4, ~ , NOv 1977, P531"539 A series of maps showing the distribution of sensitive cle~ deposits and associated lanialide~. in O ~ a w ~ Valle~f has ])men compiled. From data collected fr~n several, test b~Ings, th e sensitive cl~y has been divided intc four distinct atratig~a~hic units. Visual identification, crite~i~ ha~e been developed a~d average index properties are given. By c~mbining the surficial geology a~d the shratig~aphic profiles obtained by drilllmg it has been possible t o classify sensitive clay slopes into two geologic settings. One set, leg consists of clay at the surface and the other has a thin layer of fine sand ov~rlyimg the sensitive clay. The majority of the large retrogressive slides have occurred in slopes of the Is%ter setti~4~. 785174 A I ~ C A T I O N OF RISK ANALYSIS TO ~ PR~ICTION OF SLOPE INSTABILITY Yong~ R N; Alomso~ E; Tabba, M M Can Geotech J, Vl4, ~ , Nov 1977, P540-55~ Discusses the prediction of stability in natural clay slopes, using a probabillstic method of smalysls to account f ~ random prope~ies and ~ertalnties, rather than the usual 'factc~ of safety' method. By means of the method of alices~ the different sources of errc~ were i~c~ated into a first-order probability analysis of the simplified Bishop model in order to arrive at quar~itatlve infca~nation concerning the probability of failure. Field amd laberatazy data fro~ an i n ~ n t e d test valley slope in the O ~ a w a region were used to obtain a predicted v~lue fc~ stability of the test slope. The arelysis distinguishes between statistical uncertainty, which comes free insufficiency of available data, ~ probabilistie uncertainty, which is a measure of random heterogeneity of the soil. 78517~ ON THE I ~ O G E E S S I O N OF LAND~lW~ES IN SENSITIVE MUDDY SEDIMENTS Carson, M A Can Geotech J, VI4, N4, Nov 1977, P582-602 The relevant literature is reviewed. The theory of landslide retrogression prqposed by Odenstad, a~ the Skottorp la~slide in Sweden, is discussed, and developed into a model fc~ the prediction of retrogressior~ and far the explanation of 'flowbowl' morphology. The model is tested against selected retrogressive landslide sites far which all the necessary information is available: the agreement .between nature and theory is good. Eml~hasls is directed at the impcrtemce of the undrained shear strength of sensitive sediments~ rather than the actual m~tt~e of sensitivity of such deposits. The limitations of the model in very soft sediments are briefly pointed out.
785176 EVIDENCE OF CREEP IN STEEP NATURAL SLOPES OF CHAMPLAIN SEA CLAY Ede~ W J Can Geoteeh J, V14, ~ , NOv 1977, P620-627 Three types of evidence of deep scared creep of steep natural slopes are considered: surface manifestations such as fissures and depressions, inslinometer measuresmnts on three slopes in the Otts~a area, amd move~nents of a bridge st~perstructure spermlng a steep sided ravine. Results of measurements show that the movements are not continuous but occur in response to seasonal high levels of the groumdwater table. The implications of the movements are discussed in relation to the stability of clay slopes. 785177 RETROGRESSIVE SLOPE FAILURES AT BEAVER CREEK, SOUTH OF SASKATOON, SASKATCHEWAN s CANADA Haug, M D; Sauer, E K; Fredlund, D G Can Geotech J, VI4, N3, Aug 1977, P288-301 Active landslides are occttrring along the banks of the South Saskatchewan River at Saskatoon. A field investigation amd stability analysis indicated that a multiple retrogressive mecha ~ s m is valid in explaining the failures at Beaver Creek. Computations shewed that lateral pressures ranging from the active to something greater ~ the at-rest comdltlon teni to part the successive blocks but are not hig~ enough to stabilize the slides. It was assumed that the rate of movement of the blocks varies and probably imareases downslope. Infarmation was obtained about the soil properties in the area stud the mechanism of failure that seems to apply over a long section along the river bank south of Saskatoon. 785178 EFFECT OF FRACTUEE DEFORMATION ON FLUID PRESSURE DISI~IBUTION - AN INDICATOR OF SLOPE INSTABILITY Gale, J E; Witherspoon, P A Can Geotech J, VI4, N3, Aug 1977, P302-309 Results from laboratory and field tests on fractured rock systems have s1~;:, +l,~t ch~u%ges in fluid Pressure within a fracture can cause changes in the effective mmrmal stress that result in significant m ~ m m l dls~seements. These normal displacements cha~ge the fluid pressure distributions and hence the shear strength of the fracture system. The nature of the normal dlspl~ement (opening c~ closing of the fracture) can be detected by comparing the ratios of pressures measured at t~'o points within the fracture plane. Careful measurement of changes in fluid pressures in fractured rock slopes could be used to give an indication of an approaching instability. 785179 STABILISATION OF A SLIDE IN SAINT-JEROME, LAC SAINT-JEAN La Rochelle, p; Lefebvre, G; Bilodeau, P M Can Geotech J, VI4, N3, AUg 1977, P3~0-356 One year after the construction of a hospital in Saint-Jerome, a slide occurred in the slope behind the hospital building, followed later by three other a ~ d / slides. This paper discusses th~ causes and the mechanism of the slides, describes the corrective weeks carried out, ard evaluates their effectiveness based on different visual observations, on pore pressure and shear strength measurements, and on stability analysis.
detailed st~y of ghructural weaknesses. The remalts were subsequently used to amaly~ different mo~es of possible failure af the rock mass. The info~ion obtained is being used in redesignim~ the Copper Mountain open pit, Quebec. 785172 T ~ N T AND MAI~IRNANCE OF ROCK SLOPES ON TRANSP~ION ROUTES Peckov~, F L; Kerr, J W G Can Geotech J~ VI4, N ~ NOv 197~, I~237-507 785173 GEGLOGICAL AND GEGMORFHOLOGICAL CON~RGLS OF LANDSLIDES IN OITAWA V~TTEy, O~TARIO Franaham~ P B; Gadd, N R Can Geotech J, VI4, ~ , NOv 1977, P531"539 A series of maps showing the distribution of sensitive cle~ deposits and associated lanialide~. in O ~ a w ~ Valle~f has ])men compiled. From data collected fr~n several, test b~Ings, th e sensitive cl~y has been divided intc four distinct atratig~a~hic units. Visual identification, crite~i~ ha~e been developed a~d average index properties are given. By c~mbining the surficial geology a~d the shratig~aphic profiles obtained by drilllmg it has been possible t o classify sensitive clay slopes into two geologic settings. One set, leg consists of clay at the surface and the other has a thin layer of fine sand ov~rlyimg the sensitive clay. The majority of the large retrogressive slides have occurred in slopes of the Is%ter setti~4~. 785174 A I ~ C A T I O N OF RISK ANALYSIS TO ~ PR~ICTION OF SLOPE INSTABILITY Yong~ R N; Alomso~ E; Tabba, M M Can Geotech J, Vl4, ~ , Nov 1977, P540-55~ Discusses the prediction of stability in natural clay slopes, using a probabillstic method of smalysls to account f ~ random prope~ies and ~ertalnties, rather than the usual 'factc~ of safety' method. By means of the method of alices~ the different sources of errc~ were i~c~ated into a first-order probability analysis of the simplified Bishop model in order to arrive at quar~itatlve infca~nation concerning the probability of failure. Field amd laberatazy data fro~ an i n ~ n t e d test valley slope in the O ~ a w a region were used to obtain a predicted v~lue fc~ stability of the test slope. The arelysis distinguishes between statistical uncertainty, which comes free insufficiency of available data, ~ probabilistie uncertainty, which is a measure of random heterogeneity of the soil. 78517~ ON THE I ~ O G E E S S I O N OF LAND~lW~ES IN SENSITIVE MUDDY SEDIMENTS Carson, M A Can Geotech J, VI4, N4, Nov 1977, P582-602 The relevant literature is reviewed. The theory of landslide retrogression prqposed by Odenstad, a~ the Skottorp la~slide in Sweden, is discussed, and developed into a model fc~ the prediction of retrogressior~ and far the explanation of 'flowbowl' morphology. The model is tested against selected retrogressive landslide sites far which all the necessary information is available: the agreement .between nature and theory is good. Eml~hasls is directed at the impcrtemce of the undrained shear strength of sensitive sediments~ rather than the actual m~tt~e of sensitivity of such deposits. The limitations of the model in very soft sediments are briefly pointed out.
785176 EVIDENCE OF CREEP IN STEEP NATURAL SLOPES OF CHAMPLAIN SEA CLAY Ede~ W J Can Geoteeh J, V14, ~ , NOv 1977, P620-627 Three types of evidence of deep scared creep of steep natural slopes are considered: surface manifestations such as fissures and depressions, inslinometer measuresmnts on three slopes in the Otts~a area, amd move~nents of a bridge st~perstructure spermlng a steep sided ravine. Results of measurements show that the movements are not continuous but occur in response to seasonal high levels of the groumdwater table. The implications of the movements are discussed in relation to the stability of clay slopes. 785177 RETROGRESSIVE SLOPE FAILURES AT BEAVER CREEK, SOUTH OF SASKATOON, SASKATCHEWAN s CANADA Haug, M D; Sauer, E K; Fredlund, D G Can Geotech J, VI4, N3, Aug 1977, P288-301 Active landslides are occttrring along the banks of the South Saskatchewan River at Saskatoon. A field investigation amd stability analysis indicated that a multiple retrogressive mecha ~ s m is valid in explaining the failures at Beaver Creek. Computations shewed that lateral pressures ranging from the active to something greater ~ the at-rest comdltlon teni to part the successive blocks but are not hig~ enough to stabilize the slides. It was assumed that the rate of movement of the blocks varies and probably imareases downslope. Infarmation was obtained about the soil properties in the area stud the mechanism of failure that seems to apply over a long section along the river bank south of Saskatoon. 785178 EFFECT OF FRACTUEE DEFORMATION ON FLUID PRESSURE DISI~IBUTION - AN INDICATOR OF SLOPE INSTABILITY Gale, J E; Witherspoon, P A Can Geotech J, VI4, N3, Aug 1977, P302-309 Results from laboratory and field tests on fractured rock systems have s1~;:, +l,~t ch~u%ges in fluid Pressure within a fracture can cause changes in the effective mmrmal stress that result in significant m ~ m m l dls~seements. These normal displacements cha~ge the fluid pressure distributions and hence the shear strength of the fracture system. The nature of the normal dlspl~ement (opening c~ closing of the fracture) can be detected by comparing the ratios of pressures measured at t~'o points within the fracture plane. Careful measurement of changes in fluid pressures in fractured rock slopes could be used to give an indication of an approaching instability. 785179 STABILISATION OF A SLIDE IN SAINT-JEROME, LAC SAINT-JEAN La Rochelle, p; Lefebvre, G; Bilodeau, P M Can Geotech J, VI4, N3, AUg 1977, P3~0-356 One year after the construction of a hospital in Saint-Jerome, a slide occurred in the slope behind the hospital building, followed later by three other a ~ d / slides. This paper discusses th~ causes and the mechanism of the slides, describes the corrective weeks carried out, ard evaluates their effectiveness based on different visual observations, on pore pressure and shear strength measurements, and on stability analysis.