SOILS AND FOUNDATIONS
Print ISSN : 0385-1621
Volume 32, Issue 3
Displaying 1-13 of 13 articles from this issue
  • KOJI SEKIGUCHI, KERRY R. ROWE, K.Y. LO, TOYOKAZU OGAWA
    1992 Volume 32 Issue 3 Pages 1-14
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    This paper proposes a simple technique for minimizing computational effort when modelling practical problems which typically involve several non-linear soil materials with different plasticity parameters and joint elements. The technique is applicable to analyses performed using the pseudo-viscoplastic algorithm for solving non-linear problems. The applicability of the analysis is then evaluated by comparing the authors' calculated results with published field observations. The paper demonstrates that significant computational savings can be achieved by optimizing the viscoplasticity parameters. It is also demonstrated that the method of analysis adopted provides encouraging agreement with observed field behaviour.
    Download PDF (1394K)
  • SHIGERU GOTO, YOSHIO SUZUKI, SHINYA NISHIO, HIROSHI OHOKA
    1992 Volume 32 Issue 3 Pages 15-25
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Undisturbed samples of gravel deposit were obtained from alluvial deposits by an in-situ freezing method, and their mechanical properties were determined based on laboratory tests. The samples are considered to retain high quality, based on the fact that shear wave velocities measured both in the field and the laboratory showed good agreement. The laboratory tests were also conducted on specimens reconstituted to the density of the undisturbed samples. It was found that : (1) the undrained cyclic shear strength of the undisturbed gravels are considerably higher than those of the reconstituted ones : (2) the shear moduli of the undisturbed specimens are about 20% higher than those of the reconstituted ones, but relationships between normalized shear modulus G/G0 and shear strain are almost the same between the two : and (3) the internal friction angles of all the specimens tested are almost the same at about 40°.
    Download PDF (1617K)
  • SATORU SHIBUYA, FUMIO TATSUOKA, SUPOT TEACHAVORASINSKUN, XIAN JING KON ...
    1992 Volume 32 Issue 3 Pages 26-46
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The stress-strain relationships of various kinds of geomaterials; i.e., a cement-treated sandy soil, a sedimentary soft rock, gravels, sands and reconstituted kaolin, were examined in tests using specimens subjected to both monotonic and cyclic shear in triaxial, plane strain compression and torsional simple shear. A particular attention was paid on their stiffness at small strains, for which the deformation of specimens in triaxial and plane strain compression was measured locally over the central part with an accuracy of the strain measurement of about 0.0001%. In a series of tests performed on normally consolidated specimens, the elastic shear modulus, Gmax, was defined for small strain ranges having their limits with the order of 0.001%, below which the response was found to be practically linear elastic. The Gmax-value was hardly influenced by the rate of shearing and the type of loadings (i.e., static monotonic, static cyclic and dynamic loadings) within the small strain range. It was also demonstrated that the Gmax-value of sands was scarcely affected by the stress and strain histories as examined in tests using specimens subjected to different degrees of initial shear applied during consolidation and of over-consolidation, and to cyclic prestraining at relatively large strain levels. The results suggest that, with a supply of high-quality undisturbed samples, the Gmax-value, together with the strain level-dependent stiffness and the strength, of natural ground can be evaluated by having the results of laboratory monotonic loading tests with necessary corrections for the effects of sample disturbance. Also, the elastic shear modulus from in-situ elastic shear wave velocity can be directly used for the analyses of monotonic and cyclic problems as the effects of some factors, such as the strain level-dependency of the stiffness, are properly evaluated.
    Download PDF (2115K)
  • MARK TALESNICK, SAM FRYDMAN
    1992 Volume 32 Issue 3 Pages 47-60
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A series of cyclic loading tests was performed on undisturbed marine sediments of the Israeli continental slope. Testing was carried out in a torsional hollow cylinder device under a variety of boundary conditions, as well as in a direct simple shear apparatus. Analysis of the test data leads to the hypothesis that cyclic shear strains may be divided into irrecoverable and overall components, and that the relationship between the two takes the form of a continuous, increasing function. This function is independent of the applied boundary conditions, testing equipment and strain rate, but is dependent upon the particular soil. The relationship for the soft clay tested in the present study was found to be linear. Data published by other researchers validates the proposed hypothesis. It appears that for any particular soil, the same relationship is valid for uniform stress or strain controlled loading, as well as for irregular loading sequences.
    Download PDF (1472K)
  • KENJI ISHIHARA, S.MOHSEN HAERI, ALI A. MOINFAR, IKUO TOWHATA, SHUICHI ...
    1992 Volume 32 Issue 3 Pages 61-78
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    General feature of the Manjil earthquake of June 21, 1990 in Iran and its effects on the ground damage are described putting emphasis on the liquefaction of sand deposits and landsliding which occurred in natural slopes. The liquefaction developed on the fluvial plain in the lower reaches of the Sefidrud river is shown to have exhibited several features in common with those ever encountered in other areas under similar conditions. The landslides which occurred in the mountain flanks in the epicentral area seem to have addressed some new features on the triggering mechanism of the slide intrinsic to earthquake environments.
    Download PDF (2737K)
  • YASUSHI SASAKI, IKUO TOWHATA, KENICHI TOKIDA, KAZUHIKO YAMADA, HIDEO M ...
    1992 Volume 32 Issue 3 Pages 79-96
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    This paper concerns with the mechanism of the permanent lateral displacement of ground induced by seismic liquefaction. The present study consists of three series of shaking table tests of both large and small scales. The test results demonstrated that the ground movement occurs in the same direction as that of the total head gradient as defined in hydraulics, while a large shear distortion occurs in the liquefied sand. The horizontal displacement in a liquefied layer was found to be null at the bottom and maximal at the ground water table. It was also observed that the surface unliquefied layer, if any, moved together with the liquefied subsoil without slip. The influence exerted by a global topography should not be neglected, although the local ground condition is important as well. The effect of the seismic inertia force is not important as compared with that of the gravity force. With these findings, it is suggested that the liquefied sand undergoing lateral displacement behaves similar to liquid. This idea seems to help predict the extent of the permanent displacement of the liquefied ground.
    Download PDF (2000K)
  • IKUO TOWHATA, YASUSHI SASAKI, KENICHI TOKIDA, HIDEO MATSUMOTO, YUKIO T ...
    1992 Volume 32 Issue 3 Pages 97-116
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The permanent displacement of ground induced by seismic liquefaction is known to significantly damage lifeline networks. This paper is concerned with the prediction of the maximum possible displacement that could occur when the state of soil liquefaction continues for a sufficiently long period. The authors have so far proposed three types of analytical prediction of the ground displacement and their development is followed chronologically in this paper, while explaining the back grounds which led to respective versions. The latest model is supported by the observations of shaking table tests. It is considered therein that the liquefied soil behaves like liquid, leading to the idea that the ground displacement is governed by the minimum-energy principle. Finally, a comparison is made between observed and calculated displacements for several actual cases in the past in order to show that the proposed method of prediction gives good results in spite of its simplicity.
    Download PDF (1850K)
  • AKIRA ASAOKA, TAKESHI KODAKA
    1992 Volume 32 Issue 3 Pages 117-129
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Failure problems of saturated soils are classified in the present study into the following four types : Type I : The failure of loose and/or normally consolidated soils under fully drained loading conditions. Type II : The same soils but under perfectly undrained conditions. Type III : The failure of dense and/or overconsolidated soils under fully drained conditions. Type IV : The same soils but under perfectly undrained conditions. The soil-water coupling limiting equilibrium analysis on the basis of the critical state concept is shown possible to draw a distinction between type I, II and IV problems, and the limitations of the analysis procedure happen in solving the type problem in the above. This is demonstrated experimentally, in which seepage failure experiments in laboratory with the use of a saturated silty sand are employed to make distinctions clearly between the four types of failure problems. The definite distinctions both in failure load and failure mode appeared in the four types of experiments are summarized as follows : (1) the smallest failure load in loose sand in the undrained condition, (2) the largest failure load with the largest failure region in dense sand under undrained loading, (3) the observation of no global deformation before failure within the soil under the fully drained condition that suggests the development of very localized shear deformation in the sand. Three out of four experiments are described well by the limit analysis computation mentioned above as far as the failure load and the shape and the size of the failure region after boiling failure are concerned, and thus the type III problem is identified to be the problem that should be solved by any other means in near future.
    Download PDF (1662K)
  • JURGEN GRABE, GERD GUDEHUS
    1992 Volume 32 Issue 3 Pages 130-136
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The leaning tower of Pisa is a famous historical structure, especially in the field of soil mechanics. In this paper, the historical development of the inclination is reconstructed considering that a ground failure took place after each of the three construction phases. Model tests (scale 1 : 130) were carried out in order to predict that the tower will fail definitely, i.e. without any further disturbances, at an angle of inclination of 5.7°, which is dramatically close to the actual value of 5.5°. The estimated probability of failure rises very quickly with an increase in the angle of inclination. Conservation of the tower should be done therefore with utmost caution.
    Download PDF (1021K)
  • M.A.ABDEL RAHMAN, M.A. OTHMAN, T.B. EDIL
    1992 Volume 32 Issue 3 Pages 137-143
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    This paper presents a numerical and experimental investigation of the influence of plate flexibility on the behavior of shallow spread anchors in sand. The study shows that plate flexibility has a significant effect on soil-anchor interaction; including failure mechanism, displacement field of the soil mass around the plate, and load-displacement relationship. A finite element program utilizing an elasto-plastic constitutive model is used to study these factors. A large-scale experimental study on steel anchors of different plate thicknesses is described.
    Download PDF (894K)
  • HIDEO SEKIGUCHI, SEIKI OHMAKI
    1992 Volume 32 Issue 3 Pages 144-155
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    This paper concerns the stability against overturning of the caissons on rubble mound subjected to wave loading. A theoretical discussion is first made of the stability of a leaning caisson during wave loading, as a single degree-of-freedom system. The expression for the lower bound of driving moments sufficient to overturn a given caisson is derived. A review is then made of the damages induced to a composite breakwater, which consisted of two adjoining Stretches B and C with slightly different sizes of caissons. Attention is called for the observation that most of the caissons in Stretch B were overturned, whereas no caissons in Stretch C were brought into overturning. This fact is examined in detail in the light of the theory of overturning, making it possible to estimate the destructive wave heights that are compatible with the observed patterns of damage in Stretches B and C of the composite breakwater.
    Download PDF (1033K)
  • NEVEN MATASOVIC, MLADEN VUCETIC
    1992 Volume 32 Issue 3 Pages 156-173
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The paper focuses on the development and modelling of residual cyclic pore water pressure, u, in clay during undrained cyclic strain-controlled loading. Data obtained from a series of NGI type cyclic simple shear tests were employed. In addition to the amplitude of cyclic shear strain, γc, the number of cycles, N, and the overconsolidation ratio, OCR, a new component is incorporated in the conventional characterization of u. This new component is the volumetric threshold shear strain, γtv, of clayey soils, below which for all practical purposes u does not develop. The lack of understanding of complex clay microstructure and the associated interaction between clay particles during cyclic shearing makes the modelling of u in a manner other than curve fitting rather difficult. This is especially true in regard to the development of negative u in overconsolidated clays. A model based on the systematic curve fitting of the pore pressure data expressed in terms of γc, γtv, N and OCR is presented. The possibilities of the incorporation of such a model into existing numerical tools for simulation of the seismic and ocean wave loading response of natural soil deposits are briefly discussed as well.
    Download PDF (1683K)
  • Keizo Ugai
    1992 Volume 32 Issue 3 Pages 197-205
    Published: September 15, 1992
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Download PDF (941K)
feedback
Top