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Multiple rolling tire sinkage and drag interaction effects
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ABSTRACTS as should have been expected, with increasing angularity, decreasing particle size and increasing gradation, but among other variations difficult to summarize, this latter effect seems negligible in quartz soils and noticeable instead in feldspar and calcite. Following J. Hansen and H. Lundgrun criterion ["Hauptprobleme der Bodenmechanik", Springer-Verlag, Berlin (1960)] "but with adjusted values now predicting shearing resistance with dilatation removed . . . an equation (and limiting values of correction terms for angularity, particle size, gradation, relative density and type of mineral) represents the recommended design value for the angle of shearing resistance of cohesionless single mineral soils." In the reviewer's opinion, the paper, although far from being exhaustive, is instructive and very interesting. (App. Mech. Rev.)
41.
D. C. Kraft and H. Luming. Multiple rolling tire sinkage and drag interaction effects. SAE Paper No. 710180, Automot. Engng. Congr., Jan. 11-13, 1971. Adjacent loaded areas affect the performance of aircraft tyres operating on soil runways. To examine tyre soil sinkage and drag interaction effects for multiple-tyre landing-gears, research undertaken comprised: (I) evaluation of existing multiple-tyre test data, (2) dual-plate, verticalload tests to determine sinkage interaction effects, (3) an analysis, based on a lumped-parameter iteration technique with soil-simulation, of adjacent-load interaction, (4) full-scale experiments. Results indicate that reductions in rolling drag are obtainable by the proper use and spacing of dual and tandem tyres for operation on sandy and clay soils. The full-scale experiments are continuing. (M.I.R.A.)
42.
K. Y. Lo. The pore pressure-strain relationship of normally consolidated undisturbed clays. Pt. I, Theoretical Considerations. Can. GeotechnicalJ. 6, (4), 3 8 3 4 1 2 (November 1969). A theoretical analysis shows mathematically that the pore pressure induced by shear in saturated clays may be expressed as a sole function of major principal strain, thus eliminating the anomalies inherent in the stress theories for pore pressure. A hypothesis is developed to provide a possible mechanism of pore pressure set up in undisturbed normally-consolidated clays. Experiments on such clays of various sensitivities show that, both for isotropically and anisotropically consolidated samples, the pore pressure ratio-strain relationship is independent of the magnitude of consolidation pressures, time of sustained stress, time of consolidation and intrinsic anisotropy under both plane strain and axially-symmetric stress conditions. The effect of the intermediate principal stress may be taken easily into account so that the pore pressure set up under plane strain condition may be estimated from results of laboratory triaxial tests. The effect of strain rate was found to be small for the clays tested, and became insignificant at large strains. (J. Soil Mech. Fndn. Eng. Div., ASCE).
43.
P. Nanda Kumaran and H. C. Dhiman. A miniature earth pressure cell for dynamic studies (in English), J. Soil. Mech. Fndn. Eng. 9 (1) 3-111 (January 1970). Design, fabrication and performance of a miniature earth pressure cell for dynamic studies are described. The cell is novel as to the type of diaphragm and shape of the cell. Advantages of this cell over conventional types are listed. Results from an investigation wherein this cell was used also are included. (App. Mech. Rev.)
44.
W. Odrobinski. Finding of ultimate stress limit in subsoil, in a three-dimensional model, for horizontally loaded foundations (in Polish), Archiwum Hydrotechniki 16 (4), 541-556 (1969). Starting from the general principle of dependence of the stress tensor on the tensor of strain, as known from tests on the shape of rupture lines and from the existing solutions of the twodimensional system, author deduces the formulas describing the share of the lateral earth zones in the cases when foundations are loaded by horizontal forces. The solution pertains to systems free from changes in the state of deformation as expressed by rupture lines on the soil surface. The article presents the formula referring to non-cohesive as well as cohesive soil media, and includes equations in their differential form to describe systems of more complicated geometry. (App. Mech. Rev.)
45.
J. P. Palta, A. Parkash and I. P. Abrol. A comparison of several methods for evaluating bulk density of field soils. J. Indian Soc. Soil Sci. 17, 417-422 (1969). [Punjab Agric. Univ., Hissar, India]. The methods compared were: sampling with a core of known dimensions, sand cone method, mercury displacement, kerosene saturation, kerosene displacement using water as impregnating liquid, coating soil clods with molten wax, coating with collodion and coating soil clods with
ABSTRACTS as should have been expected, with increasing angularity, decreasing particle size and increasing gradation, but among other variations difficult to summarize, this latter effect seems negligible in quartz soils and noticeable instead in feldspar and calcite. Following J. Hansen and H. Lundgrun criterion ["Hauptprobleme der Bodenmechanik", Springer-Verlag, Berlin (1960)] "but with adjusted values now predicting shearing resistance with dilatation removed . . . an equation (and limiting values of correction terms for angularity, particle size, gradation, relative density and type of mineral) represents the recommended design value for the angle of shearing resistance of cohesionless single mineral soils." In the reviewer's opinion, the paper, although far from being exhaustive, is instructive and very interesting. (App. Mech. Rev.)
41.
D. C. Kraft and H. Luming. Multiple rolling tire sinkage and drag interaction effects. SAE Paper No. 710180, Automot. Engng. Congr., Jan. 11-13, 1971. Adjacent loaded areas affect the performance of aircraft tyres operating on soil runways. To examine tyre soil sinkage and drag interaction effects for multiple-tyre landing-gears, research undertaken comprised: (I) evaluation of existing multiple-tyre test data, (2) dual-plate, verticalload tests to determine sinkage interaction effects, (3) an analysis, based on a lumped-parameter iteration technique with soil-simulation, of adjacent-load interaction, (4) full-scale experiments. Results indicate that reductions in rolling drag are obtainable by the proper use and spacing of dual and tandem tyres for operation on sandy and clay soils. The full-scale experiments are continuing. (M.I.R.A.)
42.
K. Y. Lo. The pore pressure-strain relationship of normally consolidated undisturbed clays. Pt. I, Theoretical Considerations. Can. GeotechnicalJ. 6, (4), 3 8 3 4 1 2 (November 1969). A theoretical analysis shows mathematically that the pore pressure induced by shear in saturated clays may be expressed as a sole function of major principal strain, thus eliminating the anomalies inherent in the stress theories for pore pressure. A hypothesis is developed to provide a possible mechanism of pore pressure set up in undisturbed normally-consolidated clays. Experiments on such clays of various sensitivities show that, both for isotropically and anisotropically consolidated samples, the pore pressure ratio-strain relationship is independent of the magnitude of consolidation pressures, time of sustained stress, time of consolidation and intrinsic anisotropy under both plane strain and axially-symmetric stress conditions. The effect of the intermediate principal stress may be taken easily into account so that the pore pressure set up under plane strain condition may be estimated from results of laboratory triaxial tests. The effect of strain rate was found to be small for the clays tested, and became insignificant at large strains. (J. Soil Mech. Fndn. Eng. Div., ASCE).
43.
P. Nanda Kumaran and H. C. Dhiman. A miniature earth pressure cell for dynamic studies (in English), J. Soil. Mech. Fndn. Eng. 9 (1) 3-111 (January 1970). Design, fabrication and performance of a miniature earth pressure cell for dynamic studies are described. The cell is novel as to the type of diaphragm and shape of the cell. Advantages of this cell over conventional types are listed. Results from an investigation wherein this cell was used also are included. (App. Mech. Rev.)
44.
W. Odrobinski. Finding of ultimate stress limit in subsoil, in a three-dimensional model, for horizontally loaded foundations (in Polish), Archiwum Hydrotechniki 16 (4), 541-556 (1969). Starting from the general principle of dependence of the stress tensor on the tensor of strain, as known from tests on the shape of rupture lines and from the existing solutions of the twodimensional system, author deduces the formulas describing the share of the lateral earth zones in the cases when foundations are loaded by horizontal forces. The solution pertains to systems free from changes in the state of deformation as expressed by rupture lines on the soil surface. The article presents the formula referring to non-cohesive as well as cohesive soil media, and includes equations in their differential form to describe systems of more complicated geometry. (App. Mech. Rev.)
45.
J. P. Palta, A. Parkash and I. P. Abrol. A comparison of several methods for evaluating bulk density of field soils. J. Indian Soc. Soil Sci. 17, 417-422 (1969). [Punjab Agric. Univ., Hissar, India]. The methods compared were: sampling with a core of known dimensions, sand cone method, mercury displacement, kerosene saturation, kerosene displacement using water as impregnating liquid, coating soil clods with molten wax, coating with collodion and coating soil clods with