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Journal Articles (Geotechnical & Geoenvironmental Engineering)

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  1. Interpretation of moduli from self-boring pressuremeter tests in sand [Download]

    Title: Interpretation of moduli from self-boring pressuremeter tests in sand
    Creator: Bellotti, R.
    Description: The pressuremeter is a unique method for assessing directly the in situ shear stiffness of soils. However, the correct interpretation and application of the measured modulus must account for the relevant stress and strain level acting around the pressuremeter during the test. A method to correct the measured unload-reload shear modulus from self-bored pressuremeter tests in sands is proposed. The method has been evaluated using extensive data obtained from 47 tests performed in a large calibration chamber using pluvially-deposited silica sand and from 25 tests performed in situ in a natural deposit of relatively clean silica sand at the River Po, Italy. A consistent relationship was obtained between the corrected unload-reload shear modulus and the small strain shear modulus determined from resonant column tests and field cross-hole tests. Suggestions are given to link the measured moduli with moduli values required for geotechnical design problems. The importance of strain level, stress-strain model, yield and number of load cycles is discussed.
    Subjects: Stiffness, Field tests, Shear modulus, Site investigation, Sands, Analysis
    Date Created: 1989
  2. Rock Mass Movements Across Bedding in Kananaskis Country, Alberta [Download]

    Title: Rock Mass Movements Across Bedding in Kananaskis Country, Alberta
    Creator: Hu, X. Q.
    Description: Abstract: Rock mass movements in sedimentary rocks across bedding in Kananaskis Country, Alberta, are controlled by discontinuity orientations and topography. When bedding planes dip at less than 50-degrees, small rock masses can slide along strike joints or fall and slope angles remain unchanged. When bedding surfaces dip at 65-70-degrees, large rock masses topple and then slide or simply slide along sheeting joints or combinations of bedding surfaces and strike joints to reduce slope gradients. Block toppling and sliding models of large slope movements in highly jointed rock masses indicate that toppling mode is more critical than the sliding mode. A natural example, the 6 x 10(6) m3 Elk Ridge landslide, shows toppling from bedding planes followed by sliding car be catastrophic.
    Subjects: Rockies, Rock, Slide, Topple, Landslide
    Date Created: 1992
  3. Geotechnical engineering and frontier resource development [Download]

    Title: Geotechnical engineering and frontier resource development
    Creator: Morgenstern, N. R.
    Description: The traditionalconcepts that constitute the framework for geotechnical engineering are often insufficient on their own to provide a basis for solving geotechnical problems associated with frontier resource developments. Studies are reported on the creep of permafrost slopes, the mechanics of heave in freezing soils and the behaviour of frozen soils subjected to thaw to illustrate this. These problems are encountered in the exploration and production of hydrocarbon resources in the Arctic. Considerations of ice rheology, fundamental thermo-dynamics and heat conduction in soils are additional concepts needed to solve these problems. Other examples are drawn from the geotechnical concerns that enter into the development of the Alberta oil sands. Here the geotechnical engineer must deal with gas-saturated, diagenetically-altered sands and with deformability and strength under high temperatures. Illustrations are given of the novel forms of behaviour encountered under these conditions. Initial results are presented of pore pressures developed under undrained heating and of the theoretical relation between the rate of heating and the dissipation of pore pressures. Rankine is actually better known for his work on thermodynamics and properties of fluids and gases than for his work on earth pressure and therefore it seems fitting in a Rankine Lecture to draw attention to the significance of the main body of Rankine's work in many new areas of geotechnical endeavour.
    Subjects: Geotechnical engineering, Frontier resource development
    Date Created: 1981
  4. Indentation tests to investigate ice pressures on vertical piers [Download]

    Title: Indentation tests to investigate ice pressures on vertical piers
    Creator: Croasdale, K. R.
    Description: Controlled field and laboratory tests were performed to investigate the relationship between ice strength and the maximum ice pressures on vertical piers. The apparatus used in the field tests consisted of a flat indentor (75 cm wide) which was pushed through the ice by hydraulic rams. 27 tests were conducted on lake ice up to one metre thick. Ice pressures in the range 2.5 to 5.0 MPa were obtained for ice in good initial contact with the indentor. The ice pressures exhibited little sensitivity to variations in temperature, ice thickness and strain-rate for the range 7.5 x 10ˉ5 to 4.4 x 10ˉ3 sˉ1. The average unconfined compressive strengths obtained in the laboratory were about 20% higher than the average field ice pressures. In addition, the laboratory strengths were found to be sensitive to temperature, and to strain-rate in the range 1 x 10ˉ7 to 1 x 10ˉ3 sˉ1. The confined compressive strength was two to three times the unconfined strength. The failure modes observed in the indentation tests were similar to those predicted (before the tests) by an upper-bound plasticity mode. The ability of the model to relate small-scale ice strength to field ice pressures is discussed.
    Subjects: Ice, Strains and stresses, Ice floes, Mathematical models
    Date Created: 1977
  5. Frost heave prediction of chilled pipelines buried in unfrozen soils [Download]

    Title: Frost heave prediction of chilled pipelines buried in unfrozen soils
    Creator: Konrad, J. M.
    Description: Frost heave is an important consideration in the design of buried chilled pipelines. A procedure for calculating the amount of heave under a chilled gas pipeline is presented based on a finite-difference formulation of the heat and mass transfer in saturated soils. The frost heave of the soil is characterized in terms of the segregation potential concept developed in earlier papers by the authors. Good agreement is found between the predictions of heave obtained with this procedure and that observed in long-term full-scale experiments at a test site in Calgary, Canada. Additional calculations are presented to explore the influence of pipeline temperature, pipe insulation, and ground temperature on frost heave of buried pipelines.
    Subjects: Frost heave, Buried pipelines, Chilled pipelines
    Date Created: 1984
  6. Basic friction angles of carbonate rocks from Kananaskis country, Canada [Download]

    Title: Basic friction angles of carbonate rocks from Kananaskis country, Canada
    Creator: Cruden, D. M.
    Description: Basic friction angles of the Paleozoic carbonate rocks of Kananaskis Country, west of Calgary, Canada were determined on a tilting table to range from 21.5° to 41.3°. The basic friction angles of carbonate rocks with impurity contents under 10% increase with calcite content and grain size. Clay minerals reduce basic friction angles in carbonate rocks with impurity contents over 10%. Sliding angles from repeated tests decrease with displacements for dolostones but not for limestones. The friction angles of highly polished surfaces are 7.5 to 7.9° for dolostones and 11.8 to 13.0° for limestones, a difference attributed to the frictional properties of the minerals.
    Subjects: Tilting tables, Friction angles
    Date Created: 1988
  7. Collapse behavior of sand: Reply [Download]

    Title: Collapse behavior of sand: Reply
    Creator: Sasitharan, S.
    Subjects: Collapse behavior, Sand
    Date Created: 1994
  8. Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia [Download]

    Title: Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia
    Creator: Froese, C. R.
    Description: Abstract: Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70 degrees. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.
    Subjects: Glaciolacustrine sediments, British Columbia, Landslide, Cemented
    Date Created: 2001
  9. Seismic cone penetration test for evaluating liquefaction potential under cyclic loading [Download]

    Title: Seismic cone penetration test for evaluating liquefaction potential under cyclic loading
    Creator: Robertson, P. K.
    Description: Abstract: Impressive progress has been made in the last 25 years in recognizing liquefaction hazards, understanding liquefaction phenomena, and analyzing and evaluating the potential for liquefaction at a site. Recent findings related to the application of the seismic cone penetration test (SCPT) for the evaluation of liquefaction potential under cyclic loading are presented and discussed. The SCPT provides independent measurements of penetration resistance, pore pressures, and shear-wave velocity in a fast, continuous, and economic manner. The current methods available for evaluating liquefaction using penetration resistance are presented and discussed. Recent developments in the application of shear-wave velocity to evaluate liquefaction potential are discussed, and a new method based on normalized shear-wave velocity is proposed. Limited case-history data are used to evaluate and support the proposed correlation. A worked example is presented to illustrate the potential usefulness of the SCPT for evaluating liquefaction potential at a site.
    Subjects: Liquefaction, Seismic, In situ tests
    Date Created: 1992
  10. Shear Wave Velocity To Evaluate In-Situ State of Cohesionless Soils [Download]

    Title: Shear Wave Velocity To Evaluate In-Situ State of Cohesionless Soils
    Creator: Cunning, J. C.
    Description: Abstract: Shear wave velocity (V-s) measurements were carried out in a triaxial testing program on three different cohesionless soils. The V-s was measured using bender elements during consolidation and at ultimate steady state. After consolidation the soil samples were loaded in shear under constant strain rate triaxial compression either drained or undrained to determine their ultimate steady or critical state (USS) at lame strains. The V-s measurements were used to develop relationships between the void ratio (e), mean normal effective stress (p'), and V-s. The shear loading results were expressed within the framework of critical state soil mechanics. The results of the V-s and USS information were combined with the state parameter concept to develop an equation to use field measured V-s to estimate the in situ consolidation state within a soil. Thus, the contractive-dilative boundary with respect to vertical effective stress for large strain loading can be determined from in situ measurements of V-s. These can then be used as a design aid to determine if a soil deposit is potentially susceptible to flow liquefaction. Worked examples to illustrate the procedure are given.
    Subjects: Shear wave velocity, Laboratory testing, In situ state, Liquefaction, State parameter, Cohesionless soil
    Date Created: 1995