SOILS AND FOUNDATIONS
Print ISSN : 0385-1621
Volume 17, Issue 1
Displaying 1-7 of 7 articles from this issue
  • RAYMOND N. YONG, TAKASHI AKIYOSHI, ROBERT D. JAPP
    1977 Volume 17 Issue 1 Pages 1-12
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The random vibration method is proposed in this study for evaluation of the dynamic shear modulus of soil using the apparatus developed by Hardin, and the results are compared with that obtained by the standard sinusoidal test.The soil specimen made of two kinds of clay and sand were placed in the triaxial cell, and twisted at the top by sinusoidal or random forces through the magnetic coils under uniform confining pressure and drained condition. The shear modulus of soil by sinusoidal vibration was computed from the resonant frequency of the soil specimen-top cap coupling system, and that by random vibration was from the expected frequency which was deduced from the narrow-band process theory. In this research study, shear strain amplitude was very small (less than 10-5), and the equivalent damping constant of soil was less than 0.05.If the test apparatus-specimen coupling system produces an apparent nonsymmetry in the frequency response function with respect to the resonant frequency, variations in the evaluation of the informations on the response characteristics of the system over a wide range of frequency result creating the inconsistencies in computation of the shear moduli from the random and sinusoidal vibration tests. Larger differences between the shear moduli by both methods are observed at low confining pressures.
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  • TAKASHI CHOU
    1977 Volume 17 Issue 1 Pages 13-21
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    A method to analyze the concrete lining of tunnel taking passive loads into consideration is proposed. The basic assumptions used are given as follows : (1) The structural system of the tunnel lining is an arch under the plain strain condition supported elastically at the ends and (2) passive loads acting on the lining are induced in proportion to displacement of the lining toward the surrounding rock over void between the lining and the rock. Using a model, which is almost the same as the tunnel lining of the Shinkansen of Japanese National Railways, many numerical results are obtained for various loading patterns, heights of the rock mass, thickness of the lining and the voids. From the results, characteristics of passive loads associated with magnitude and shape of active loads, the thickness and the void are discussed. Stress reducing effects of the passive loads are significant. But the effects are reduced by the void. Finally, rough standards of the allowable height of the rock mass are presented.
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  • YOSHIAKI YOSHIMI, KOHJI TOKIMATSU
    1977 Volume 17 Issue 1 Pages 23-38
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    Shaking table tests were conducted on models of rigid structures placed on saturated sand in order to study the pore pressure development in the sand near the structure and to study the factors which influenced the settlement of the structure. The settlement records of reinforced concrete buildings during the Niigata earthquake of 1964 were reviewed for comparison with the model test results.The studies showed : (1) The excess pore pressure developed below the center of the model structure was smaller than that away from the structure. (2) The ratio of the excess pore pressure to the initial effective stress below the center of the model structure decreased as the structure became heavier. (3) For both the model and the prototype the settlement of the structure decreased as the width of the structure increased for a given depth of liquefaction. (4) A pair of rigid walls embedded on both sides of the model structure had a considerable effect on reducing the excess pore pressure below the structure and a marked effect on reducing the settlement of the structure.
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  • MOTOHISA HARUYAMA
    1977 Volume 17 Issue 1 Pages 39-51
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    In order to clarify the deformation characteristics of volcanic deposits, "Shirasu", drained triaxial compression tests were performed on compacted specimens having several densities. Isotropic compressibility and deformation behaviour in the early stage of shearing were discussed, and on the some properties compared Shirasu with Toyoura standard sand. Here, the attention up to the point of minimum volume during shear was given. It is shown in the study that Shirasu has a higher compressibility than Toyoura sand, and that the relationships among stress ratio, volumetric strain, and shear strain are formulated by exponential and logarithmic functions. Also, the influence of stress path on the deformation of Shirasu is discussed on the basis of repeated loading test results.
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  • K.S. SANKARAN, M.S. SUBRAHMANYAM
    1977 Volume 17 Issue 1 Pages 53-64
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
    The basic Mass-spring dashpot model has been modified to take into account the relevant factors which have not been taken in the basic model. For a given site the spring constant and damping ratio are functions of the size and mass of footing and exciting moment. However, it has been shown for a given site, the dynamic soil modulus, ks, is the property of the soil and is independent upon the boundary test conditions. ks can be evaluated from a single field vibration test.A procedure is given to predict the resonant frequency and peak amplitude for vertical vibrations based upon modified Mass-spring-dashpot model. The new procedure takes care of the influence of the exciting moment on spring constant and damping ratio in terms of dimensionless parameters α, β and γ. The test results of Vicksburg and Eglin as well as Novak's tests results (which represent a spectrum of soil conditions and machine foundations) have been analysed and found that the prediction of resonant frequency and peak amplitude can be successfully carried out by performing a single field vibration test and using the modified Mass-spring-dashpot model.
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  • Shinichiro Matsuo, Takeaki Fukumoto
    1977 Volume 17 Issue 1 Pages 87-97
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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  • Hiroyuki Nakamura
    1977 Volume 17 Issue 1 Pages 99-109
    Published: March 15, 1977
    Released on J-STAGE: February 29, 2008
    JOURNAL FREE ACCESS
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