SOILS AND FOUNDATIONS
Print ISSN : 1341-7452
Volume 35, Issue 3
Displaying 1-14 of 14 articles from this issue
  • TOSHIHISA ADACHI, FUSAO OKA, TAKEHIRO HIRATA, TADASHI HASHIMOTO, JUNIC ...
    1995 Volume 35 Issue 3 Pages 1-13
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The aim of this paper is to study the geotechnical and/or mechanical behavior of sensitive Eastern Osaka clay using the test results of clay sampled in the Tsurumi district. For this paper, we have carried out a series of tests for sensitive clay sampled in the eastern Osaka, Japan. The unconfined compression tests, laboratory vane tests, oedometer tests, isotropic and anisotropic consolidation tests, and the isotropically and anisotropically consolidated undrained tests were carried out to clarify the strength-deformation characteristics and to determine the strain-rate effect and yielding characteristics. Undrained cyclic triaxial tests were also performed to obtain the effect of cyclic loading on the deformation. In addition, isotropically consolidated undrained tests for specimens trimmed with several different angles to the sedimentation plane and undrained torsional tests were conducted related to the initial structural anisotropy.
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  • SIEWANN TAN, NAIM MUHAMMAD, G.-P. KARUNARATNE
    1995 Volume 35 Issue 3 Pages 15-22
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    In the use of jute fabric for the layered clay-jute geotextile-sand method for land reclamation, it is important to determine the interface behavior between the jute geotextile and various clay types commonly found in dredged seabed soils. Since jute is used to separate and support thin sand seams to form a horizontal drainage layer on top of a soft clay slurry, the interface behavior between the jute and the slurry must be examined. The adhesion on the interface between the jute and the clay slurry is measured using the incremental penetration of a suspended endweighted jute sheet under an incremental load into a prepared clay slurry with various moisture contents, in order to obtain the interface stress value under a quasi-static condition. The effects of sheet width and sheet type were investigated earlier, and found to have a negligible effect on the interface adhesion for the water content range tested. In order to examine the effects of clay-type, several mixtures of Kaolin-Bentonite in fixed proportions were prepared to produce clays of liquid limits ranging from 100% to 400%. The interface adhesion between the jute and four samples of Kaolin-Bentonite mixes at various water contents from two to six times the liquid limits were measured using the vertical sheet test. These mixes included clay types with liquid limits from 100% to 400%, thus allowing the nature of jute/slurry interaction to be studied for a wide range of clay type. When the water contents are normalized by the liquid limits, it was observed that the interface adhesion values fall into a very narrow behaviour band, thus making it possible to estimate the available interface strength between jute and clay slurry based on water contents.
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  • Y.P. VAID, A. SAYAO
    1995 Volume 35 Issue 3 Pages 23-29
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A study of sand deformation under proportional loading under generalized stress conditions is presented. The loading includes a variety of stress paths in which the principal axes of stresses have a constant inclination to the axes of the vertically water deposited specimens. This was intended to capture the effects of inherent anisotropy in sand during proportional loading. It is shown that under such loading conditions increments of volumetric and maximum shear strains depend both on the initial stress and density state as well as on the inclination of principal stresses to the material axes.
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  • HIDEO SEKIGUCHI, KATSUTOSHI KITA, OSAMU OKAMOTO
    1995 Volume 35 Issue 3 Pages 31-42
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A closed-form solution related to the wave-induced pore pressure changes in cohesionless deposits, was derived in the research discussed in this paper. The poro-elastoplastic solution allows for the cumulative contraction of soils under cyclic loading in a simple yet workable way, permitting an integrated assessment of liquefaction due to oscillatory excess pore pressure as well as residual pore pressure. The theoretical performance compares well with the pore pressure response of a fine-grained sand bed that was observed in a centrifugal standing-wave test with viscous scaling introduced. In addition, a chart indicating the susceptibility of a wide range of cohesionless soils to liquefaction from standing waves is presented by making use of the closed-form solution, with emphasis on the effect of partial drainage.
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  • AKIRA ASAOKA, MASAKI NAKANO, G.S.K. FERNANDO, MITSUO NOZU
    1995 Volume 35 Issue 3 Pages 43-53
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    When a soft clay foundation under embankment loading is considered, settlement behavior is affected by the mass permeability and by the magnitude of applied load intensity, which is normalized by the initial undrained bearing capacity. Using these two parameters, the characteristic consolidation settlement behavior of a clay foundation can be represented by a family of S shaped curves. The range of mass permeability affecting residual settlements is confined to a narrow limit. For an embankment foundation, when these two parameters are known, settlement behavior can be determined uniquely. The effects of improvement of mass permeability by sand drains on a clay foundation are investigated using the macro element method (Sekiguchi et al., 1986). The sand drains improve the mass permeability to 30-300 times that of the non-treated ground. The above findings are applied to two case studies. In the first, where the ground is treated with sand drains under a high applied load it is found that only settlement observations can be used to assess the usefulness of sand drains in this ground. The other case is on coral soils which exhibit high permeability and a high initial undrained bearing capacity compared with common clay deposits. The effectiveness of sand drains in this ground is evidenced by a significant decrease in residual settlement.
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  • H.B. POOROOSHASB
    1995 Volume 35 Issue 3 Pages 55-59
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A principle of similarity applicable to saturated sands under the so called one gravity (1-g) model testing, as opposed to centrifugal testing say, is developed. The study is a fairly rigorous treatment of some work reported earlier by the Author and his then supervisor, the late Professor K. H. Roscoe, more than three decades ago, Roscoe and Poorooshasb (1963) and a further expansion of a study presented recently, Poorooshasb and Ishihara (1993). The development of the principle is carried out using the mixture theory and two special constitutive models. The first approach uses the constitutive model CANAsand to express the mechanical behavior of the solid phase. The second constitutive model treats the solid phase of the soil-water system as a poro-elastic material. It is shown that with a proper choice of state parameters it is possible to achieve similarity between two systems, the model and the prototype say, under quasi static loading conditions in both cases (poro-elastic and CANAsand model). When dealing with dynamic loading, however, similarity can be achieved only if the soil skeleton is assumed to be poro-elastic. With the CANAsand model the behavior of the prototype can not be simulated by a model. This finding is of paramount significance : it casts a doubt over the validity of all shaking table tests carried out thus far.
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  • KATSUTADA ONITSUKA, ZHENSHUN HONG, YUTAKA HARA, SHIGEKI YOSHITAKE
    1995 Volume 35 Issue 3 Pages 61-70
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Two alternative approaches to the conventional e-log p method for determining yield stress are critically examined in this paper, and their advantages and limitations are identified. The yield stresses defined in both alternative approaches are also theoretically verified as identical for the oedometer test data. A comparison of the advantages and limitations of both alternative approaches suggests that the ln(1+e)-log p approach should be used to interpret the oedometer test data for natural clays, and the defined yield stress can be interpreted as being responsible for the critical state of structure collapse. Systematic analyses on the oedometer test data for undisturbed Ariake clays and Shimabara clay demonstrate that it is valid to use the ln(1+e)-log p approach for determining the yield stress and both the compression and swelling indices of natural clays. In addition, some analysis implications are also given for useful parameters, such as, the critical-state pore pressure parameter in predicting the undrained strength of overconsolidated clays and the compression index ratio in evaluating the aging effect of natural clays. Finally, Nagaraj's sample disturbance degree concept based on oedometer test data is extended to take into account both the effects of stress release and mechanical disturbance. The analysis results indicate that the defined degree of sample disturbance can reflect the combined extent of stress release and mechanical disturbance during sampling and handling.
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  • GUIDO GOTTARDI, ROY BUTTERFIELD
    1995 Volume 35 Issue 3 Pages 71-82
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Estimation of the displacement of shallow, rigid, sand-supported footings when subjected to general, planar loading and unloading is a fundamental but, as yet, inadequately understood problem. The paper presents extensive new data on the load-displacement response and vertical, horizontal and rotational displacement trajectories of such a model footing derived from a series of precise experiments carried out at the University of Padova. A simple, new transformation applied to both the horizontal and moment load-components, and their associated displacements, is shown to provide a unified interpretation of the results of inclined-central and vertical-eccentric load tests. Displacement trajectories of the footing produced by quite general load-paths, including unloading, are also presented together with a comprehensive set generated by horizontal and moment loading tests at constant vertical load. Key features of the displacement responses are identified and discussed, in particular in relation to the geometrical properties required of a plastic potential curve if the displacements are to be interpreted in a framework of work-hardening plasticity.
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  • TAKEJI KOKUSHO, YUKIHISA TANAKA, TADASHI KAWAI, KOUJI KUDO, KOUICHI SU ...
    1995 Volume 35 Issue 3 Pages 83-95
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    During the Hokkaido-Nansei-Oki Earthquake, a high-land area around the foot of the volcano, Mt. Komagatake, in Hokkaido in Northern Japan experienced liquefaction inflicting damage caused by differential settlement in more than forty houses in the area. Several geotechnical site investigations were carried out to study the cause of the damage at a typical liquefaction site. Initial surveys including trenching disclosed that Holocene rock debris avalanche deposit originated from the volcano with 70 to 80% of gravel content located immediately underneath one damaged house actually liquefied and settled. By means of bore-hole drilling, penetration testing and geophysical exploration, the cross-sectional profile of the rock avalanche gravel layer was identified. The shear wave velocity of the upper part of the layer was found to be unexpectedly lower than 100 m/s. In order to quantitatively evaluate the liquefaction potential of the gravel layer, an undrained cyclic triaxial test was performed on large intact samples obtained using the in-situ freezing sampling. The stress ratio measured in the test was lower than the seismic induced stress ratio estimated from maximum surface accelerations in nearby earthquake recording sites, justifying the earthquake-induced liquefaction. In comparison with previously investigated properties of Pleistocene gravels, low values in relative density, shear-wave velocity and penetration resistance of this gravel have been highlighted, indicating a rather unique environment in forming the rock debris avalanche layer.
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  • JAROSLAV FEDA, JAN BOHAC, IVO HERLE
    1995 Volume 35 Issue 3 Pages 97-104
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A simple stress path - for uniaxial confined (K0-) loading - has been chosen to demonstrate the effect of stress probing on the value of the coefficient of earth pressure at rest K0. Two materials were used - reconstituted loess and medium sand - and two levels of hydrostatic stress probing (about 20 and 100 kPa). In the first case, with loess, no structural changes were observed. In the latter case, with sand, the soil structure changed partially. Various apparatuses were used : common and true triaxial and biaxial, and the results compared. Triaxial test results were identical and more or less confirmed Jaky's relation and the relationship proposed by the senior author, as well as biaxial tests with dense sand. Cam-clay overpredicted the K0-values. K0-coefficients measured on loose sand in the biaxial apparatus were lower than those of the triaxial apparatus. This difference was considered to be due to the stiffer response of biaxial specimens resulting from kinematic confinement.
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  • KA-CHING SAN, TAMOTSU MATSUI
    1995 Volume 35 Issue 3 Pages 105-109
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Application of the proposed strain-based failure judgment method based on generalized plasticity theory is presented. In the generalized plasticity theory, the complete performance of the model is dependent on the Mf/Mg ratio parameter. In this technical note a hyperbolic relationship between Mf/Mg ratio and void ratio is proposed. It was determined that the proposed hyperbolic relationship compared very well with the test data. The model was used for a Class-A test walls prediction. The agreement between the predicted failure load and actual failure load was found to be excellent in the granular backfill wall prediction.
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  • D.N. SINGH, P.K. BASUDHAR
    1995 Volume 35 Issue 3 Pages 111-115
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The technical note is related to the prediction of lower bound stability numbers of a trapdoor embedded in a saturated homogeneous cohesive soil under undrained conditions, using discrete elements in conjunction with nonlinear programming. For various embedment ratios, the effect of the mesh pattern on the results has been studied and generalized mesh patterns have been proposed for both shallow and deep trapdoors. A comparison of the results with those available in the literature reveals that for deep trapdoors the present method gives better lower bounds and for shallow trapdoors the results are in good agreement.
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  • Shinji Takeuchi, Keiji Hara, Masashi Nakano
    1995 Volume 35 Issue 3 Pages 129-137
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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  • Takeaki Fukumoto, Yoshiyuki Morii
    1995 Volume 35 Issue 3 Pages 139-142
    Published: September 15, 1995
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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