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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. Estimating liquefaction induced ground settlements from CPT for level ground [Download]

    Title: Estimating liquefaction induced ground settlements from CPT for level ground
    Creator: Zhang, G.
    Description: Abstract: An integrated approach to estimate liquefaction-induced ground settlements using CPT data for sites with level ground is presented. The approach combines an existing CPT-based method to estimate liquefaction resistance with laboratory test results on clean sand to evaluate the liquefaction-induced volumetric strains for sandy and silty soils. The proposed method was used to estimate the settlements at both the Marina District and Treasure Island sites damaged by liquefaction during the Loma Prieta, California, earthquake on 17 October 1989. Good agreement between the calculated and measured liquefaction-induced ground settlements was found. The major factors that affect the estimation of liquefaction-induced ground settlements are also discussed in detail. The recommendations for taking the effects of these factors into account in estimating liquefaction-induced ground settlements using the proposed CPT-based approach are presented. It is suggested that the proposed method may be used to estimate liquefaction-induced settlements for low- to medium-risk projects and also to provide preliminary estimates for higher risk projects.
    Subjects: Sand, Earthquake, Settlements, In situ testing, Liquefaction
    Date Created: 2002
  4. Single fluid jet-grout strength and deformation properties [Download]

    Title: Single fluid jet-grout strength and deformation properties
    Creator: Coulter, S.
    Description: Abstract: The use of sub-horizontal jet-grout columns in the construction of soft ground tunnels is a popular method to provide excavation support. The sequential installation of jet-grout columns in a tunneling environment will result in the jet-grout columns being loaded in a staged manner, resulting in the jet-grout material properties and installation order affecting the magnitude and distribution of surface settlements and face deformations. A laboratory program was carried out to quantify the short-term (< 24 h) development of strength and stiffness of a grout with a composition similar to that found in the construction of jet-grout columns. The laboratory tests were conducted at 8 degrees C to simulate the ground temperatures. Also the laboratory test cylinders were insulated to simulate the boundary condition differences between 600-mm-diameter jet-grout columns in soil and the 76-mm-diameter laboratory samples.
    Subjects: Jet-grout columns, Grout strength, Grout stiffness
    Date Created: 2006
  5. Analysis of foundation deformations beneath the Syncrude tailings dyke [Download]

    Title: Analysis of foundation deformations beneath the Syncrude tailings dyke
    Creator: Alencar, J.
    Description: Abstract: The paper presents the results obtained in the finite element simulation of 8 years of construction of a section of Syncrude's tailings dyke, which is located in northern Alberta and has been used to store oil sand mining waste. The site investigation for the construction of this dyke indicated that a region of the foundation contained a presheared, overconsolidated clay shale lying practically horizontal at about 20 m depth. Significant horizontal displacements have occurred along this layer. The section analyzed in this work is the one which showed the largest horizontal movements in the foundation. High pore pressures have been measured along this section, and the lateral displacements measured in the foundation have reached values over 25 cm. The major purposes of the finite element analyses were to identify the factors that have significantly influenced the deformation mechanisms and to determine a combination of parameters, within the acceptable range of values for each material, that would reproduce satisfactorily the field observations. Linear, nonlinear, and effective stresses analyses were carried out. The total stress analyses underestimated the displacements measured in the field very significantly. The displacements calculated by the effective stress analyses are in very good agreement with the measured values, and the combination of parameters necessary to reach those results are within the acceptable range of variability for each material involved, based on laboratory test results. The interpolation of the pore pressures based on the piezometer measurements and their incorporation into the analyses as known quantities at each stage of the loading process was found to be relatively simple and efficient, causing a substantial improvement of the results compared with the total stress analyses.
    Subjects: Effective stress modeling, Shear zone, History matching, Tailing dyke, Deformation analysis
    Date Created: 1994
  6. 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
  7. 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
  8. 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
  9. 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
  10. Collapse behavior of sand: Reply [Download]

    Title: Collapse behavior of sand: Reply
    Creator: Sasitharan, S.
    Subjects: Collapse behavior, Sand
    Date Created: 1994