SOILS AND FOUNDATIONS
Print ISSN : 0385-1621
Volume 14, Issue 4
Displaying 1-8 of 8 articles from this issue
  • YUDHBIR, A. VARADARAJAN
    1974 Volume 14 Issue 4 Pages 1-12
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A laboratory investigation is made on the undrained behaviour of two heavily overconsolidated saturated clays during shear. The effect of heavy overconsolidation on undrained behaviour of saturated clays is markedly different as compared to that for low degree of overconsolidation and it is function of clay type. The strength envelope is highly nonlinear for heavily overconsolidated clays at low stress levels. Increase of qfc' is much pronounced at high overconsolidation rations. The pore water pressure parameter A at failure is very much dependent on the type of clay and the stress system used. For the first time development of shear stress, pore water pressure with strain and OCR is discussed. The pore water pressure parameter A increasing with strain at low OCR values converges to a low strain-independent value at a critical OCR value for each clay and then decreases with strain for high OCR values leading to a steady, strain-independent, A value. Tangent modulus values are given as a function of OCR and confining pressure for use in analysis of foundation engineering problems in the clay deposits under undrained condition. The investigation provides valuable information in the much needed high OCR range of low stress levels where very little data is available.
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  • V. THANIKACHALAM, R. SAKTHIVADIVEL
    1974 Volume 14 Issue 4 Pages 13-24
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A critical review of grain size criteria for protective filters of cohesionless base soil is presented. From an analysis of the available experimental data and observations, it is shown that the finer sized base material has profound influence on grain size criteria. The allowable grain size ratio for stable filter performance increases with decreasing size of the base material. This increase is more pronounced if the grain size ratios were based on finer sized particles of filter and base materials. The uniformity coefficient of filter material increases with the decreasing sizes of base soil. A design procedure is suggested for both uniform and graded filters wherein, the influences of base particle size and the interdependency of the uniformity coefficient of filter material with the various grain size ratios of filter to base materials are taken into account.
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  • MASANOBU ODA, JUNICHI KONISHI
    1974 Volume 14 Issue 4 Pages 25-38
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The deformation of granular material was simulated by an assembly of cylinders (made of photoelastic material) packed at random in a two-dimensional simple shear apparatus. From the detailesd observations on the change of granular fabric due to shear, and from the analyses of interparticle contact force among grains, we obtained some experimental facts which must be taken into account in proposing a granular model of sand.With the increase of shear stress in the simple shear test and direct shear test, the normals Ni to the contact planes tend to concentrate toward the maximum principal stress axis. This tendency of the concentration of Ni is not determined by the magnitude of applied shear displacement but by the intensity of mobilized stress ratio τ/σN. The preferred direction of Ni gradually rotates with the rotation of principal stress axes during shear deformation. The sliding in microscopic scale at contact is, at any one instant, confined at some preferred contacts. According to the microscopic study of granular fabric of sand deformed in the direct shear apparatus, the similar characters are also observed.
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  • MASANOBU ODA, JUNICHI KONISHI
    1974 Volume 14 Issue 4 Pages 39-53
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    On the basis of the experimental evidences for the simple shear test of two-dimensional granular model and for the direct shear test of sand, some fundamental problems such as (1) the orientation of the principal stress axes and (2) the relation between the principal axes of stress and those of strain increment are discussed to make the deformation and strength behaviours of granular material clear from a theoretical point of view. The distribution law of contact force, which makes the determination of mean contact force at each contact possible, is successfully applied to calculate the theoretical value with respect to the mobilized stress ratio and the inclination angle of the maximum principal stress axis in the simple shear test. The rotation of the principal stress axes during simple shear occurs in the process of increasing stress ratio, and the principal axes of stress and of strain increment do not generally coincide with each other, at least up to the peak stress ratio. The equations obtained theoretically accord well with the experimental results performed by the present authors and Roscoe, et al. The same principle in regard to the mechanism of strain hardening is also applicable to the direct shear test of sand.
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  • TOSHIHISA ADACHI, MASAHISA OKANO
    1974 Volume 14 Issue 4 Pages 55-73
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    It is required to construct a more general constitutive equation for soils in order to analyze three-dimensional boundary-value problems in the field of soil mechanics. Since soils are regarded as work-hardening and rate sensitive materials with dilatancy, the equation must be the one which can describe the soil behaviors due to those properties.So far the researches concerned with the constitutive equation of soils may be divided into two categories, i.e., (i) the deformation characteristics at the equilibrium state and (ii) the rate sensitive properties.The objective of this study is to construct a more general and realistic constitutive equation for fully saturated normally-consolidated clays by unifying the results of above two major approaches. Namely, Roscoe's critical state energy theory for clays is extended so that it explains the rate sensitive property by using Perzyna's theory of elasto/viscoplastic continuum and some empirical evidences.It can be concluded that the proposed constitutive equation can more generally describe the behaviors of clays such as creep, stress relaxation and constant strain rate shear processes than those by other investigators, although there remains a work to refine the equation. The equation is expressed in terms of the second order tensor field. Thus, one can apply it to three dimentional problems by means of the finite element method.
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  • IICHIRO KONO
    1974 Volume 14 Issue 4 Pages 75-85
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The finite element method has been applied to the analysis of seepage problem in steady state as well as the finite difference method, but rarely in nonsteady state. The aim of this study is to extend the application of the finite element method to the analysis of nonsteady seepage problem.Firstly, this paper describes the principle of the finite element method in nonsteady seepage problem and the procedure of the analysis, especially on the techniques for calculating the variation of free surface and for determining the position of seepage-out point. Secondly, an example is shown : the analysis of the seepage through an earth dam with a core and a horizontal drainage, in nonsteady state.
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  • Hideo Hanzawa, Masanori Shima
    1974 Volume 14 Issue 4 Pages 97-105
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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  • Sukeo O-hara, Fumio Yasunaga, Nobuo Fujii
    1974 Volume 14 Issue 4 Pages 107-114
    Published: December 15, 1974
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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