Norihiko Miura
Saga University
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Featured researches published by Norihiko Miura.
Computers and Geotechnics | 1996
Muhammed Alamgir; Norihiko Miura; H.B. Poorooshasb; Madhira R. Madhav
Abstract A simple theoretical approach to predict the deformation behaviour of soft ground reinforced by columnar inclusions such as stone columns./granular piles, sand compaction piles, lime or cement columns, etc., is presented in this paper. The analysis is performed based on the deformation properties of the column material and the surrounding soil. The interaction shear stresses between the column and the surrounding soil are considered to account for the stress transfer between the column and the soil. The solution is obtained by imposing compatibility between the displacements of the column and the soil for each element of the column-soil system. Numerical evaluations are made for a range of parameters to illustrate the influence of various parameters on the predictions. The proposed method is verified with finite element analysis and a reasonable agreement is obtained between the predictions.
Geotextiles and Geomembranes | 1990
Norihiko Miura; A. Sakai; Y. Taesiri; T. Yamanouchi; K. Yasuhara
Abstract This paper deals with model and field tests for investigating the mechanism of reinforcement by a polymer grid in suppressing non-uniform settlement of pavements constructed on soft clay ground. A series of laboratory tests on reinforced and unreinforced model pavements in a soil tank indicates that the polymer grid is useful for suppressing non-uniform settlement of pavement under cyclic loading. Deformation analysis by FEM is carried out to make clear the reinforcement effect of a polymer grid in a model pavement. To investigate the performance of a polymer grid in practice, a test road of 300 m length with six sections of different kinds of pavement is constructed on soft clay ground. The function of a polymer grid is discussed by comparing the pavements made by conventional and reinforced methods.
Computers and Geotechnics | 1995
D.T. Bergado; Jinchun Chai; Norihiko Miura
Abstract The behavior of a reinforced embankment on soft Bangkok clay has been analyzed by plane strain finite element method. The finite element analysis considers the selection of proper soil/reinforcement properties according to the relative displacement pattern of upper and lower interface elements. The large deformation phenomenon is simulated by updating the node coordinates, including those of the embankment elements above the current construction level, which ensures that the applied fill thickness simulates the actual field value. A full scale test reinforced embankment with a vertical face (wall) on Bangkok clay has been analyzed by the proposed finite element method, and the numerical results are compared with the field data. The response of a reinforced embankment on soft ground is principally controlled by the interaction between the reinforced soil mass and soft ground and the interaction between the grid reinforcement and the backfill soil. The tension in reinforcement and lateral displacement of the wall face varied during consolidation of foundation soil. The maximum tension force occurred in the reinforcement layer placed at the base of reinforced mass, due to bending of the reinforced mass resulting from differential settlements. It is considered necessary to account for the permeability variation of the soft ground foundation in the finite element analysis.
Computers and Geotechnics | 1996
H.B. Poorooshasb; Muhammed Alamgir; Norihiko Miura
Abstract A simple numerical scheme is used to evaluate the magnitude and form of the negative skin friction on both rigid (e.g. concrete) and deformable (e.g. gravel) piles. The study includes piles extended to bedrock as well as the socalled floating piles. The position of the neutral depth associated with the floating piles is of particular interest (at this position the sign of the friction on the pile changes from negative to positive) and is discussed in some detail.
Journal of Geotechnical and Geoenvironmental Engineering | 2009
Jinchun Chai; J. P. Carter; Norihiko Miura; Hehua Zhu
A modified method is proposed for predicting the lateral displacements of the ground caused by installation of soil-cement columns. The method is a combination of the original method derived on the basis of the theory of cylindrical cavity expansion in an infinite medium and a correction function introduced to consider the effect of the limited length of the columns. The correction function has been developed by comparing the solutions obtained using the spherical and the cylindrical cavity expansion theories for a single column installation. Both the original and the modified methods have been applied to a case history reported in the literature, which involves clay soils, and the predictions are compared with field measurements. The advantage of the modified method over the original method is demonstrated. Finally, the modified method has also been applied to a case history involving loose sandy ground, and the calculations show that the method can also be used for this type of soil provided that appropriate consideration is given to the volumetric strain occurring in the plastic zone of soil surrounding the soil-cement columns.
Geotextiles and Geomembranes | 1994
N Sabhahit; P. K. Basudhar; Madhira R. Madhav; Norihiko Miura
By modifying Janbus generalized procedure of slices (GPS), the stability of a reinforced embankment constructed on a non-homogeneous clay deposit of finite depth is analysed to compute the factor of safety. The non-circular critical surface corresponding to the minimum factor of safety is obtained by a sequential unconstrained minimization technique in conjunction with a conjugate direction method for a multidimensional search and a quadratic interpolation technique for a unidimensional search. The effect of the thickness of the desiccated zone and the variation of undrained shear strength of clay with depth on the factor of safety is considered in the analysis. The influence of the tensile reinforcement force on the location of the critical surface is presented. The effects of the tensile reinforcement force and its orientation as well as the number of reinforcing layers on the stability of embankment have also been studied. The results obtained from the present analysis are compared with solutions reported in the literature.
Computational Mechanics–New Frontiers for the New Millennium | 2001
S.L. Shen; Jinchun Chai; Norihiko Miura
ABSTRACT In Column Approach and/or Column System methods, soil-cement columns are installed in a pillar-shaped condition with varying lengths. In the calculation of settlement and bearing capacity of composite ground, the stress ratio between column and surrounding soil is required. This paper is aimed to elucidate the stress transferring mechanism for a column-slab improved composite ground under road pavement based on finite element analysis. The results show for a column-slab system, the floating columns are more economical than end bearing column. Analytical results also show that the stress ratio decreases exponentially with the increase of the thickness of slab and improvement ratio, however, it increases with the increase of length-diameter ratio of column.
Transportation Research Record | 2004
Shui-Long Shen; Jie Han; Norihiko Miura
Fourteen model soil-cement columns were installed in two containers in the laboratory to investigate the influence of mixing energy consumption on the unconfined compressive strength of soil-cement mixtures by varying mixing conditions. The variables of mixing conditions included cement content, speed of installation (mixing down and up), rate of mixer rotation, number of mixing cycles, and column length. Electric power was measured during the installation of all the model columns. The factors that influenced the mixing energy consumption during the installation were evaluated, and a relationship between the mixing energy consumption and the unconfined compressive strength of soil-cement mixtures was developed. This relationship was compared with that obtained in the laboratory soil-quicklime mixing tests from another study. The test results show that the unconfined compressive strength increases with an increase of mixing energy consumption, up to a threshold value. Any further increase of the energy does not provide a significant contribution to the strength of soil-cement mixtures.
Geotextiles and Geomembranes | 1986
N. Fukuda; T. Yamanouchi; Norihiko Miura
Abstract The design of steep reinforced embankments using high tensile polymer grids has to be formulated making several assumptions. The present paper deals with laboratory tests and instrumented embankments constructed to investigate the validity of the assumptions made. Laboratory tests were conducted using a soil container with one layer of grid. Test results obtained from two kinds of grid condition were found to be in agreement with the proposed design method based on ‘tie-back-wedge-analysis’. A vertical faced embankment and an embankment with a sloping face were constructed using horizontal layers of grid reinforcement. Measurements of the tensions in targets were were found to be considerably less than those predicted by the design method. These studies reveal that the reinforcing effect is greater than that assumed in the design since the fill material is integrated with polymer grids laid in the embankment. It is suggested that such an integration effect should be incorporated in future design methods.
Computers and Geotechnics | 1987
D.T. Bergado; Norihiko Miura; J.C. Chang; M. Danzuka
Abstract This paper presents the application of probabilistic slope stability model based on variance reduction method on the Nong Ngoo Hao (NNH) test embankment and the probabilistic settlement evaluation of AIT test embankment using the nearest-neighbor method. The NNH embankment was constructed to failure. Sample autocorrelations were obtained from corrected vane shear test data as well as from the Dutch cone test data in both horizontal and vertical directions. The results showed that using a design criteria of probability of failure of 10 −3 , a design safety factor of 1.12 is recommended for 3-D analysis. In 2-D analysis, the variance reduction method yielded lower probabilities of failure compared to an earlier work based on Monte Carlo method. For the AIT test embankment, the statistical data for the occurrence of fine sand and silt lenses in the soft Bangkok clay were obtained and the inclusions were probabilistic settlement prediction in conjunction with the method of Skempton and Bjerrum and Lacasses approximation showed reasonable agreement with the observed values.