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60. Wheeled skidder performance on sloping terrain
100
ABSTRACTS
57.
F. W. Chen. Soil mechanics and theorems of limit analysis. J. Soil Mech. Fndns Div., ASCE, 95 (SM2), 493-518 (March 1969). An attempt is made to exhibit the plastic limit theorems in terms more familiar to the civil engineer. The interpretation of a continuous velocity region as the limiting case of infinitely many rigid blocks separated by surfaces of discontinuity provide an excellent technique for obtaining energy dissipation needed for upper bound calculations on plastic limit load. Similarly, the intuitive approach of imagining a pin-connected truss to support loads is shown to provide an excellent technique for obtaining lower bounds. Also a graphical procedure is introduced to eliminate much of the tedium associated with the construction of a stress field. The problems of the loaded truncated wedge and the wedge under unilateral pressure are treated as illustrative examples. Then the general strip foundation is solved. Upper and lower bounds are plotted and are seen to be rather close. Friction effects on the bearing capacity of foundations are also discussed. (Author's summary.)
58.
L. Domaschuk and H, N. Wade. A study of bulk and shear moduli of a sand. J. Soil Mech. Fndns Div., ASCE, 95 (SM2), 561-581 (March 1969). The stress-strain relationship of a micaceous sand is investigated by separating the volumetric and deviatoric components. Isotropic compression tests are used to investigate the bulk modulus of the sand prepared at different densities and subjected to different levels of stress. The shear modulus of the sand is investigated by constant mean normal stress triaxial compression tests. The tests are performed under varying conditions of relative density, mean normal stress and deviatoric stress. Graphical and analytical solutions for the bulk and shear moduli are developed from the experimental data. (Author's summary.)
59.
M. ,L Dumbleton. The classification and description of soils for engineering purposes: A suggested revision of the British system. R o a d Research Lab., RRL-LR 182, 48 pp. (1968), The report suggests and describes a revised British system for soil classification, including a code for the supplementary description of soils and their site condition. The first section of the report discusses the principles and uses of soil classification systems. Section 2 is a concise statement of the suggested British Soil Classification System (BSCS). The rest of the report gives definitions of the terms used in the classification, describes the full laboratory procedure and a rapid method for carrying out the classification of soils, and compares the suggested system with the existing British system and with similar systems in use in the U.S.A., France and Switzerland. (U.S, Gov. Res. Dev. Rep., 10.5.69, PB- 182646.)
60.
H. G. Gibson, R. L. Hartman, D. L. Gochenour, Jr. and H. W. Parker. Wheeled skidder performance on sloping terrain. Agricultural Engineering, 50 (3), 152-154 (March 1969). Wheeled skidders, articulated 4-wheel drive logging tractors, are being used more and more in Appalachian hardwood logging. This study was conducted on two sites where the slopes are generally steep, averaging 40 per cent.
61.
K. Grant. A terrain evaluation system for engineering. Technical papers, 2, 28 pp. (April 3, 1968). A terrain classification scheme suitable for engineering purposes should be one that engineers can apply and interpret. No special skills should be required for its implementation. The scheme should also be compatible with a data collection, storage, and retrieval medium, so that information may be stored for future use. The principles and concepts evolved for such a scheme of terrain classification are discussed in detail in this paper. A scheme operating at four levels of generalization, known as province, terrain pattern, terrain unit and terrain component, is suggested. The terrain covered by each level of generalization is defined and a numerical system of labelling for each level of generalization is proposed and explained The methodology of o~erating the suggested terrain classification system is discussed and the role of aerial photographs is examined. The classification is based first on aerial photograph intert~retation, but the classification so obtained is not regarded as valid until it has been checked in the field. The implementation of the terrain classification scheme and its engineering interpretation are considered. (U.S. Gov. Res. Dev. Rep. 10.3.69, PB-180800.)
ABSTRACTS
57.
F. W. Chen. Soil mechanics and theorems of limit analysis. J. Soil Mech. Fndns Div., ASCE, 95 (SM2), 493-518 (March 1969). An attempt is made to exhibit the plastic limit theorems in terms more familiar to the civil engineer. The interpretation of a continuous velocity region as the limiting case of infinitely many rigid blocks separated by surfaces of discontinuity provide an excellent technique for obtaining energy dissipation needed for upper bound calculations on plastic limit load. Similarly, the intuitive approach of imagining a pin-connected truss to support loads is shown to provide an excellent technique for obtaining lower bounds. Also a graphical procedure is introduced to eliminate much of the tedium associated with the construction of a stress field. The problems of the loaded truncated wedge and the wedge under unilateral pressure are treated as illustrative examples. Then the general strip foundation is solved. Upper and lower bounds are plotted and are seen to be rather close. Friction effects on the bearing capacity of foundations are also discussed. (Author's summary.)
58.
L. Domaschuk and H, N. Wade. A study of bulk and shear moduli of a sand. J. Soil Mech. Fndns Div., ASCE, 95 (SM2), 561-581 (March 1969). The stress-strain relationship of a micaceous sand is investigated by separating the volumetric and deviatoric components. Isotropic compression tests are used to investigate the bulk modulus of the sand prepared at different densities and subjected to different levels of stress. The shear modulus of the sand is investigated by constant mean normal stress triaxial compression tests. The tests are performed under varying conditions of relative density, mean normal stress and deviatoric stress. Graphical and analytical solutions for the bulk and shear moduli are developed from the experimental data. (Author's summary.)
59.
M. ,L Dumbleton. The classification and description of soils for engineering purposes: A suggested revision of the British system. R o a d Research Lab., RRL-LR 182, 48 pp. (1968), The report suggests and describes a revised British system for soil classification, including a code for the supplementary description of soils and their site condition. The first section of the report discusses the principles and uses of soil classification systems. Section 2 is a concise statement of the suggested British Soil Classification System (BSCS). The rest of the report gives definitions of the terms used in the classification, describes the full laboratory procedure and a rapid method for carrying out the classification of soils, and compares the suggested system with the existing British system and with similar systems in use in the U.S.A., France and Switzerland. (U.S, Gov. Res. Dev. Rep., 10.5.69, PB- 182646.)
60.
H. G. Gibson, R. L. Hartman, D. L. Gochenour, Jr. and H. W. Parker. Wheeled skidder performance on sloping terrain. Agricultural Engineering, 50 (3), 152-154 (March 1969). Wheeled skidders, articulated 4-wheel drive logging tractors, are being used more and more in Appalachian hardwood logging. This study was conducted on two sites where the slopes are generally steep, averaging 40 per cent.
61.
K. Grant. A terrain evaluation system for engineering. Technical papers, 2, 28 pp. (April 3, 1968). A terrain classification scheme suitable for engineering purposes should be one that engineers can apply and interpret. No special skills should be required for its implementation. The scheme should also be compatible with a data collection, storage, and retrieval medium, so that information may be stored for future use. The principles and concepts evolved for such a scheme of terrain classification are discussed in detail in this paper. A scheme operating at four levels of generalization, known as province, terrain pattern, terrain unit and terrain component, is suggested. The terrain covered by each level of generalization is defined and a numerical system of labelling for each level of generalization is proposed and explained The methodology of o~erating the suggested terrain classification system is discussed and the role of aerial photographs is examined. The classification is based first on aerial photograph intert~retation, but the classification so obtained is not regarded as valid until it has been checked in the field. The implementation of the terrain classification scheme and its engineering interpretation are considered. (U.S. Gov. Res. Dev. Rep. 10.3.69, PB-180800.)