Articles

  1. A Comparative Study of Geotechnical Behavior of Lime Stabilized Pond Ashes from Delhi Region Download Article

    Raju Sarkar, S.M. Abbas, and J.T. Shahu
    • Article Type: Research Article
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    • Pages (273-279 )
    • No of Download = 341

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    Pond ash is a pozzolanic material and can be stabilized with lime. It can also be stabilized with other commonly available stabilizers like cement, bentonite etc. This paper deals with both geotechnical characteristics of the pond ashes alone as collected from various thermal power stations in the National Capital Region, Delhi and also when they are stabilized using lime. The purpose of mixing this additive with pond ash is to improve the strength, deformability, volume stability (shrinking and swelling), permeability, erodibility, durability etc. of the mix for their use in the road construction.

  2. Partial Sediment Dredging Method Developed for Conserving Ecosystem and Recycling Sedimentary Material Download Article

    Naoki Miyazato, Mizuki Osaki, Masahito Toda, Ken Kimura, Ayato Furukawa and Toru Aoi
    • Article Type: Research Article
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    • Pages (280-284 )
    • No of Download = 607

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    In this research, we report about the improvement of a sediment dredging method and cases of application. The flocculation tank and the sedimentary sand tank were made one for a small space technology. All parts of this technology can be transported by one truck. An inverter was used so that the frequency can be changed. Accordingly, we can change the rotational frequency of the dredged pump. The flocculation tank was placed below a screen. The hydro-extractor discharge rate of sludge increased approximately twofold.  This dredging method does not need a large space. We propose that this dredging method can be used at lakes in parks, small ponds, and other places. Furthermore, we propose that dredged sludge can be used for agricultural applications.

  3. Inquiry of the Value of Parks in the Characteristics and Use of Park Through Urban Revival Planning Projects in Maebashi City Download Article

    Shinya Tsukada, Tetsuo Morita and Akira Yuzawa
    • Article Type: Research Article
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    • Pages (285-289 )
    • No of Download = 446

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    Recently, the interest about environment of park rises. But it does not become clear enough, that environment of park in local city. The purpose of this paper is to clarify the evaluation on the urban parks in Maebashi city, Gunma Prefecture, Japan. One example of a local city in Japan, there are a stock of many parks from post-war urban revival planning projects, and aims to consider the evaluation of development by park planning and use through an understanding. We researched on the relation of these parks planning and using by the historical materials. Result of investigation, we obtain the characteristic and the subject in urban revival planning projects Maebashi city. In addition we consider the changing use of these parks, Maebashi park, Shikishima Park, and Hirose Riverside park road.

  4. Image Analysis Techniques on Evaluation of Particle Size Distribution of Gravel Download Article

    G. H. A. Janaka J. Kumara, Kimitoshi Hayano and Keita Ogiwara
    • Article Type: Research Article
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    • Pages (290-297 )
    • No of Download = 554

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    Particle size distribution of granular materials is usually evaluated by sieve analysis test. In this research, an image analysis technique using ImageJ is proposed to evaluate particle size distribution of gravels. On particular conditions, some differences of gradation curves determined by sieve analysis and image analysis were observed. Based on the results, several aspects related to image analyzing are discussed in the paper. They include appropriate evaluation of particle grain size in image analysis, minimization of shadow effects appeared in images, effects of number of particles adopted for sieve analysis and image analysis and so on. It was found that grain size in image analysis should be defined appropriately to compare the gradation curves by the two methods. Probably, due to light effects, it was also observed that black color sheets are better than white color sheets to place particles. This method can be used as an in-situ test method since this method needs only a camera and a computer.

  5. Challenges and Improvement Solutions for Tunis’ Soft Clay Download Article

    Bouassida M. and Klai M.
    • Article Type: Research Article
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    • Pages (298-307 )
    • No of Download = 6347

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    The design of foundations resting on Tunis soft clay still remains a very challenging issue to address. However some works have been dedicated to the characterization and the study of behavior of this problematic soil on which recent investigations more focused on improvement solutions. This paper first summarizes the geotechnical properties of Tunis soft clay on the basis of data collected from experienced projects and results obtained from laboratory tests. It has been discussed how Tunis soft clay properties can be affected by disturbance? Some correlations are also suggested from recorded data. Besides, the study of behavior of built embankments on Tunis soft clay is analyzed from numerical computations carried out by 2D version of Plaxis software. It is then concluded, that the improvement of Tunis soft clay by classical techniques like geodrains, sand piles and stone columns is necessary to guarantee the short term and long term stability of structures to be built on such weak soil. Illustrated case histories show the efficiency of these improvement techniques as competitive solutions compared to piled foundation that remains the most used especially for building projects in Tunisia but not cost effective.

  6. Effect of Soil Reinforcement on Shear Strength and Settlement of Cohesive-Frictional Soil Download Article

    Bestun J. Nareeman and Mohammed Y. Fattah
    • Article Type: Research Article
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    • Pages (308-313)
    • No of Download = 1733

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    This study investigates the effect of soil reinforcement using geonet on the shear strength, consolidation and swelling of silty soil. The tests that carried out are classified into two categories: First; tests on soil without reinforcement and second tests on soil with reinforcement. The loading test was conducted on small scale model using different layers of reinforcement. The results showed that the shear strength parameters could be improved by using geonet reinforcement. Moreover, the settlement and swelling of silty soils are decreased by using geonet.

  7. Changes in Bottom Sediment Caused by Construction of the Airport Island in Ise Bay, Japan Download Article

    Maki OYAGI, Motohiro KAWASE Akiko YOKOYAMA and Akihiko YAGI
    • Article Type: Research Article
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    • Pages (314-317 )
    • No of Download = 671

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    In order to investigate the impact on the marine environment from the construction of the Chubu International Airport Island in Ise Bay, Japan; a careful observation was made to clarify the bottom sediment condition and the composition of benthic fauna at some stations located from east to south of the airport island. Grain size compartment, moisture percentage, ignition loss, carbon, nitrogen, phosphorus and sulfur were measured.  The ignition loss values in surface sediment in 2003 averaged 150% times higher than that of data in 2007.  The benthic fauna revealed the species and number of individuals were very few.  Organic matter increased, the species structure of the benthos was made poor.  The average number of individuals and species compared before and after the Airport construction clearly showed a remarkable decrease after the construction. This phenomenon might reflect the ongoing progress of eutrophication and oxygen depletion around the airport island sea.

  8. Proposal of Simple Measurement Method for Evaporation Rate by Using Oxygen Isotopic Ratio Download Article

    Satoshi Miyahara and Hiroyuki Ii
    • Article Type: Research Article
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    • Pages (318-324 )
    • No of Download = 788

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    The purpose of this study is to develop simple method for estimating evaporation rates of water using oxygen isotopic ratio. From the laboratory test, strong negative correlation between average humidity and oxygen isotopic ratio change per unit evaporation rate was observed and humidity was clarified to be important parameter. The evaporation rate can be calculated from the amount of change of the oxygen isotopic ratio during evaporation. The amount of change of the oxygen isotopic ratio per unit the amount of change of evaporation rate estimated empirically under each humidity condition. The amount of evaporation per year in the Inawashiro Lake in Fukushima was estimated to be 590mm/year from the relation between humidity and evaporation rate and the estimated value was in agreement with the calculation result of previous research, 600mm/year. Therefore, the simple estimation method is effective for estimation of evaporation rate of an actual lake or a pond especially in a dried area because the measurement error is small under the low humid condition.

  9. Effect of Sand Gradation on The Behavior of Sand-Clay Mixtures Download Article

    Mohammad S. Pakbaz and Ali Siadati Moqaddam
    • Article Type: Research Article
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    • Pages (325-331 )
    • No of Download = 484

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    In contrast to the clean sands the behavior of sands with fines have complexities that has made it difficult for researchers to reach a general framework for their evaluation and this problem exist today for researchers. In this research work the effect of increasing clay content and also of the gradation of sand on the behavior and shear strength properties of over-consolidated mixtures of sand-clay was evaluated. one of the parameters of over-consolidated soils is the parameter m from the relationship of shear strength for over-consolidated clays. The compacted over-consolidated samples of mixtures of various sand gradations with 15, 20, 30 and 40 percent clay were tested in direct shear. the result showed that at a particular sand gradation, with the increase in clay content the shear strength and the value of m decreased. also at constant clay content with decrease in sand grains size the shear strength and vale of parameter m decreased.

  10. Groundwater Contamination Due to Irrigation of Treated Sewage Effluent in the Werribee Delta Download Article

    Hiroyuki Ii, Ataru Satoh, Masanobu Taniguchi, Matt Kitching, George Croatto, Bruce Shelley and Graeme Allinson
    • Article Type: Research Article
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    • Pages (332-338)
    • No of Download = 948

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    The Werribee River, groundwater and Melbourne’s treated sewage effluent (or recycled water) are used for irrigation water in the Werribee Delta. Groundwater beneath the Werribee delta may be contaminated by the recycled water. The mixing ratios of the sea water, upstream groundwater and recycled waters for delta
    groundwater were calculated from water chemistry. The mixing ratio of the recycled water varied from 10 to 30% at all depths and delta groundwater was found to be largely comprised by irrigated recycled water. The NO3 - contamination of delta groundwater is thought to be caused by recycled water and agricultural use of fertilizers. A high mixing ratio of sea water was found at 30 m in depth and this zone was thought to be a salt-water wedge.

  11. Numerical simulation of 2D crack growth with frictional contact in brittle materials Download Article

    Kai Zhang, Qing Yang.and Jing-Cai Jiang
    • Article Type: Research Article
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    • Pages (339-342)
    • No of Download = 397

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    In this paper, the extended finite element method (XFEM) is applied in modeling the 2D crack growth with frictional contact under uniaxial compress load in the rock-like materials. First, the implementation of XFEM is incorporated into a commercial FEM software (ABAQUS) in which the constitutive law of linear elasticity and the criterion of maximum tangential stress (MTS) is adopted. Then a user subroutine is coded and incorporated into ABAQUS to simulate the growth of wing crack with the frictional contact in the crack faces. A series of numerical simulations of 2D plane strain rectangle with central pre-set crack are carried out, and computed results are compared with experimental ones. The effects of inclination and coefficient of the friction of the pre-set cracks on growth of wing cracks are examined. In addition, size effect of materials is also investigated, and these jobs contribute to the understanding of 2D crack growth.

  12. A Study on the Behaviour of Geogrid Encased Capped Stone Columns by the Finite Element Method Download Article

    Mohammed Y. Fattah and Qutaiba G. Majeed
    • Article Type: Research Article
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    • Pages (343-350)
    • No of Download = 902

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    The finite element method is utilized as a tool for carrying out different analyses of stone column–soil systems under different conditions. A trial is made to improve the behaviour of stone columns by encasing them by geogrid as reinforcement material. The program CRISP-2D is used in the analysis of problems. The program allows prediction to be made of soil deformations considering Mohr–Coulomb failure criterion for elastic-plastic soil behaviour. A parametric study is carried out to investigate the behaviour of ordinary and encased floating stone columns in different conditions. Different parameters are studied to show their effect on the bearing improvement and settlement reduction of the stone column. These include the length to diameter ratio (L/d), the area replacement ratio (as) and thickness of the stone cap layer. It was found that for encased stone column, the bearing improvement ratio increases with the increase of length to diameter (L/d) even when (L/d) ratio becomes more than 8 for all area replacement ratios. This means that in case of encased stone column, there is no limitation on the effective (L/d) ratio. The strength of stone column increases when encased with geogrid compared with ordinary stone column and the increasing in bearing capacity (q treated /q untreated) is higher when (L/d) increases. The use of stone cap above the stone column increases the bearing improvement ratio and decreases the settlement for all L/d ratios. The increase in stone cap thickness increases the bearing improvement ratio and decreases settlement for all L/d ratios.