Articles

  1. IMAGE PROCESSING FOR GEOTECHNICAL LABORATORY MEASUREMENTS Download Article

    Erica Elice Saloma Uy and Tirawat Boonyatee
    • Article Type: Research Article
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    • Pages (1964-1970)
    • No of Download = 934

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    This research is an effort to apply image processing techniques for non-contact determination of 2D and 3D displacements of specimens in a triaxial apparatus. For the 2D measurement, a calibration procedure is applied to correct image distortions before the positions of interested points are tracked by the pyramidal optical flow algorithm (Lucas and Kanade, 1981). By considering the change of position, the displacement of an interested point can be determined. The results are compared with the measurements obtained from LVDTs and are well agreed. For 3D measurement, calibration, rectification, correspondence and 3D re-projection are performed. It is verified by an isotropic compression test of a cylindrical sponge in a triaxial apparatus. The estimated displacement and discharge of water are compared with the measured ones and are well agreed. The repeatability and resolution of the developed system are found to be in the order of 0.006 cm and 0.004 cm, respectively.

  2. MODELING OF FLUID INTRUSION INTO POROUS MEDIA WITH MIXED WETTABILITIES USING PORE-NETWORK Download Article

    Junichiro Takeuchi, Wataru Sumii and Masayuki Fujihara
    • Article Type: Research Article
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    • Pages (1971-1977)
    • No of Download = 853

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    Water or air intrusion into a porous medium filled with the other fluid is affected by many factors such as size, configuration, and connectivity of pores as well as the contact angle of grain. To deal with these pore-scale factors, a pore-network model is utilized. According to the modified Delaunay method, pore-networks are extracted from randomly packed spherical grains computed by the distinct element method. Displacement processes of two immiscible fluid in a porous medium with mixed wettabilities, are modeled in an invasion percolation manner, in which simultaneous invasion is allowed, and water retention curves in drainage and imbibition processes are computed. The results obtained show that hydrophobic grains do not have just a strong effect on the water retention properties, but also the amount of water/air residue after a drainage/imbibition process depends on the invasion rate.

  3. COMPARISON OF CONSOLIDATION CURVES FOR REMOLDED MUD VOLCANO OF SIDOARJO, INDONESIA Download Article

    Luky Handoko, Noriyuki Yasufuku, Ryohei Ishikura and Ahmad Rifa’i
    • Article Type: Research Article
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    • Pages (1978-1982)
    • No of Download = 519

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     Sidoarjo mud volcano (Lusi) is one of the most challenging problems regarding to the compressibility of fine grained soils in Indonesia. Understanding about compressibility behavior is essential to construct appropriate remediation program for this problems. Consolidation test has been conducted to investigate the compressibility behavior of Lusi mud volcano. In this study, the laboratory test result is compared with estimated value derived from several empirical equations. A simple equation can be used to predict e-log σ’ curve very well by using the correlation between initial void ratio (e0) and void ratio corresponding to unit pressure (e1); and correlation between compression index (Cc) and physical properties of soils, such as liquid limit (wL) or natural water content (wn). This equation predict better than other available equations in literature when compared with laboratory test of Lusi mud volcano.

  4. WATER QUALITY AND COMPOSITIONS OF THE PHYTOPLANKTON AND ZOOPLANKTON BEFORE AND AFTER BUILDING CONSTRUCTION IN LAKE FUKAMI-IKE, JAPAN Download Article

    Hiromi Suda, Masaaki Tanaka, Maki Oyagi, Megumi Nobori and Akihiko Yagi
    • Article Type: Research Article
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    • Pages (1983-1988)
    • No of Download = 596

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     Lake Fukami-ike is a small monomictic and eutrophic lake, located in southern Nagano Prefecture in central Japan. Water quality improvement was expected from maintenance of farm village drainage and waterfront function was carried out for town activation in 1992. However, no blue-green algal bloom outbreak had occurred before. We studied the water quality and compositions of the zooplankton and phytoplankton before and after building a bulkhead maintenance construction. Large decreased values for NO3-N, NH4-N and NO2-N were 1.87→0.50 gNm-2 (26.7%), 1.49→0.78 gNm-2 (52.3%) and 0.085→0.030 gNm-2 (35.3%), respectively. Aphanizomenon flos-aquae (Cyanophyceae) were dominant in the summer; some species of the genus Fragilaria were dominant among phytoplankton during study periods. The dominant species of zooplankton during study periods were Keratella cochlearis (Rotatoria); smaller than Cyclops vicinus (Crustaceae) were dominant species of zooplankton before the construction.

  5. INVESTIGATIONS ON THE HYDRAULIC CONDUCTIVITY AND PHYSICAL PROPERTIES OF SILT AND SLUDGE AS POTENTIAL LANDFILL CAPPING MATERIAL Download Article

    Hamidi Abdul Aziz, Wong Chin Yik, Harris Ramli and Salem S. Abu Amr
    • Article Type: Research Article
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    • Pages (1989-1993)
    • No of Download = 969

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    Landfills have been the most common methods of municipal solid waste disposal in developing countries. Landfill capping is a containment technology that forms a barrier between the contaminated media and the surface. Presently, the commonest capping materials for landfills are sandy material and laterite soil. The permeability and the strength of the material against slope failure are among the important parameters to be considered. The objective of this research was to study the suitability of silt from Ulu Kinta dam in Malaysia and sludge (domestic wastewater sludge and water treatment sludge) as alternative materials for landfill capping. Both materials have little commercial values in Malaysia to date. The two materials were mixed with varying proportions of pure silt, 20, 40, 60, 80 and 100% of the sludge. Investigations were made on the hydraulic conductivity and physical properties of the mix. The results showed that silt material has a moderate hydraulic conductivity with k of value 4.81x10-4 cm/s, poor cohesion strength, 7.64 kN/m2 and good friction angle, 36.2°. Sewage sludge has the best properties among the three materials, good hydraulic conductivity with k of 2.07x10-6 cm/s, moderate cohesion strength, 8.95 kN/m2 and very high friction angle of 45.7°. Water treatment sludge’s hydraulic conductivity, k was 2.9x10-6 cm/s which is good, but having poor cohesion strength and friction angle of 6.16 kN/m2 and 6.1°, respectively. Silt and sludge were also mixed to test whether the method improves the properties of the final product; the result was negative. The use of 100% sewage sludge exhibited better results than others.

  6. OPTIMUM CONDITIONS OF OYSTER SHELLS AS MATERIAL COVERING SEDIMENT AND INHABITATION SIMULATION OF INTERNAL LOAD USING ECOSYSTEM MODEL Download Article

    Masaaki Kondo, Yuji Kato and Takamitsu Kajisa
    • Article Type: Research Article
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    • Pages (1994-2001)
    • No of Download = 616

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     A remediation program for a canal with water quality problem will be carried out in the future, and internal load from the bottom sediment can be new problem. Remediation measure against internal load was investigated by using oyster shells as covering material. So that shell-covered sediment experiments and numerical experiments were carried out. Pre-treatment such as graining and heating might be in vain, and non-heated shells of chip or powder size will be optimum. Properties of nutrient elusion were also obtained at the experiments. Numerical experiment was investigated on reducing patterns against external load and internal load to evaluate the various remediation measures by using ecosystem model added shell-covered sediment model. Only shell covering might have the small effect of water quality improvement. Good water quality is expected to be archived in the long period by a combination of reducing external load and applying bioresources.

  7. ASSESSEMENT OF LIQUEFACTIONIN BOUMERDES (ALGERIA) USING RELIABILITY ANALYSIS Download Article

    Benahchilif Souad and Zendagui Djawad
    • Article Type: Research Article
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    • Pages (2002-2006)
    • No of Download = 684

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    A destructive earthquake of magnitude Mw=6.8 hit the region of Boumerdes and Algiers (Algeria) on May 21, 2003. Evidence of soil liquefaction was observed ina site located in the vicinity of Boumerdes. The results of traditional analysis of soil liquefaction potential using simplified procedures are usually presented in terms of safetyfactor. However, these methods do not take into account inherent variability which is expressed in terms of liquefaction probability related to safety factors. An answer to this problem can be found by reliability analysis. In this study, a practical reliability based method is used for assessing the soil liquefaction potential. As an application, the Boumerdes region belongs to the Tell Atlas thrust of Algeria is investigated for liquefaction potential. The investigated are based on in situ tests in which the results of SPT are analyzed.It was found that even with a safety factor of 1.34, the soil still has a liquefaction probability about 30.85% for the given design earthquake.

  8. STUDY ON ASSESSING THE VALUE OF THE TENGUIWA IRRIGATION CANAL Download Article

    Shinya Tsukada, Tetsuo Morita and Akira Yuzawa
    • Article Type: Research Article
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    • Pages (2007-2010)
    • No of Download = 548

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    In Japan, following changes in socioeconomic conditions, such as financial deterioration, an increase in social capital, and a decrease in population, ideas about infrastructure improvement have greatly changed. Recently, irrigation canals possessing historic value have attracted the attention of the public as assets for community development. The present study focused on the Soja district, in which many historical and cultural resources exist but where these resources have not been developed. A questionnaire was administered to the local residents and revealed the value of the Tenguiwa Irrigation Canal as an environmental asset. The present study also examined the relationship between the value of the Tenguiwa Irrigation Canal as an environmental asset and the direction of community development in the Soja district. 

  9. CONVERSION OF A DECOMMISSIONED OXIDATION LAGOON INTO A FUNCTIONAL WETLAND Download Article

    Jeram Mallis, Rhiannon Hamilton, Scott Rayburg and Melissa Naeve
    • Article Type: Research Article
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    • Pages (2011-2017)
    • No of Download = 823

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    This study proposes an ecologically valuable reuse for a decommissioned oxidation lagoon at the Altona Treatment Plant in Victoria, Australia, which could be replicated elsewhere. Previous design attempts for this project had failed due to the potential risk they posed to both the surrounding environment and the Treatment Plant itself. Therefore one of the objectives was to undertake multiple assessments to mitigate these risks. The most important of these, and the focus of this paper, was the determination of the optimal source and quantity of water needed to sustain the wetland. Potential water sources included: water from a nearby estuarine swamp; treated class C or class A effluent from the treatment plant; and rainfall-fed runoff from the treatment plant site. Through an analysis of cost and quality of the available water sources, it was determined that locally captured rainfall-fed runoff with Class-A recycled water as a backup supply was the most feasible. In addition, hydrologic modelling revealed that this source could maintain flow in the wetland year round, even in drought years. 

  10. MODELLING OF PERMEABILITY CHARACTERISTICS OF SOIL-FLY ASH-BENTONITE CUT-OFF WALL USING RESPONSE SURFACE METHOD Download Article

    Jonathan R. Dungca and Joenel G. Galupino
    • Article Type: Research Article
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    • Pages (2018-2024)
    • No of Download = 572

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    In order to prevent the contamination the groundwater, by restricting the horizontal movement of leachate, cut-off walls were recommended [1]. Currently, one of the factors in designing cut-off walls is to provide efficient and relatively inexpensive means of containing contaminants. In order to obtain acceptable permeability, it was suggested by Baxter [2] to provide a mix of 96% soil and 4% bentonite in the design of cut-off walls, but bentonite is relatively expensive, thus the viability of fly ash as a replacement for bentonite was considered. Soil mixtures were proposed and rigorous laboratory tests were performed to determine the individual properties of the said soil mixtures. Tests for specific gravity, soil index property, relative density, microscopic characterizations, elemental composition and permeability were performed to garner data that were utilized for the Response Surface Method Permeability models. The minimum permeability requirements for the cut-off wall were achieved using various mixtures of soil-bentonite-fly ash.

  11. DEVELOPMENT OF FLORA IN RELATION TO WATER MANAGEMENT IN OBASUTE-OIKE IRRIGATION POND, JAPAN Download Article

    Teruo Arase, Tetsuo Okano, Yoshiyuki Uchikawa and Taizo Uchida
    • Article Type: Research Article
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    • Pages (2025-2029)
    • No of Download = 511

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    In order to clarify the factors affecting the species diversity of plant communities around an irrigation pond, we surveyed Obaste-oike Irrigation Pond in Nagano Prefecture, Japan. The pond is comprised of three subdivided ponds, Kami-ike, Naka-ike, and Shimo-ike. Despite being adjacent to each other and connected by streams, the water levels in the three ponds differ. Five plant communities were studied, and one or two survey plots were selected in each community along each subdivided pond. A 32-m2 quadrat was established in each plot of grassland, and a 400-m2 quadrat was established in each plot of forest. The results of the distribution of species revealed that approximately 40% of the species were endemic to each subdivided pond in the terrestrial communities, whereas over 60% were endemic in the hydrophytic communities. To increase species diversity in irrigation ponds, especially in hyrdophytic communities, we suggest that dividing the ponds into several zones with distinct water levels and managing them in a sustainable manner is important.

  12. EXPERIMENTAL INVESTIGATION OF TSUNAMI WATERBORNE DEBRIS IMPACT ON STRUCTURES Download Article

    Omolbanin Farahmandpour, Abdul Kadir Marsono, Masine Md.Tap, Suhaimi Abu Bakar and Parham Forouzani
    • Article Type: Research Article
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    • Pages (2030-2035)
    • No of Download = 935

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    Tsunamis and hurricanes cause a lot of damage to structures. The water-borne debris that is produced during these natural disasters can cause a considerable damage to the many structures if they have not been constructed for such loads. Tsunami field survey observations have indicated that the damage is aggravated by heavy objects like wooden logs, automobiles, boats, storage barrels and other containers. This paper presented the results of experimental study for the quantification of the debris impact force on the structures. Moreover, it studied the formulas, which have been specified in the recently published tsunami-resistant engineering design guidelines (FEMA P-646, 2012) and the Coastal Construction Manual (FEMA P-55, 2011) with the results of experiment.

  13. AS, SR, ZN, FE, MN, PB AND CU CONCENTRATIONS OF SEAWEED AT THE KII PENINSULA, JAPAN Download Article

    Hiroyuki Ii
    • Article Type: Research Article
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    • Pages (2036-2042)
    • No of Download = 794

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     Seaweed from locations ranging from Osaka Bay facing the metropolis to the southern top of the Kii Peninsula facing the Kuroshio Current at the Kii Peninsula were measured for concentrations of arsenic (As), strontium (Sr), zinc (Zn), iron (Fe), manganese (Mn), lead (Pb) and copper (Cu). Except for one location at Kanayama neighboring a closed Pb mine, metal concentrations in seaweed were variable but their average values agreed with the world data. Therefore the influence of the Kuroshio Current water and Osaka Bay water on metal concentration in seaweed was found to be small. As and Sr concentrations in brown seaweed were higher than those in red and green seaweed at the Kii peninsula except at Kanayama, Fe concentrations in green seaweed were higher than those in brown and red seaweed and Zn, Mn, Pb and Cu concentrations in brown, red and green seaweed were all the same. Total Fe, Zn, Mn, Pb and Cu loads of mine waste water from the closed mine into the Kanayama Bay were 4,000 to 6,000, 3,000 to 5,000, 180, 20 and several kg per year. Zn and Fe concentrations in seaweed at Kanayama were remarkably high being 10 to 100 times that of the world value. Mn and Pb concentrations in seaweed at Kanayama were 10 times higher than the world values. Cu concentrations of red and green seaweeds at Kanayama were little higher than the world values.

  14. DISTRIBUTION CHARACTERISTICS OF THE ANNUAL NITROGEN LOAD IN YAMATO RIVER BASIN IN 2011 Download Article

    Masanobu Taniguchi and Hiroyuki Ii
    • Article Type: Research Article
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    • Pages (2043-2049)
    • No of Download = 402

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    Although there was not enough data to calculate the amount of nitrogen load in the Yamato River basin, some estimation methods were applied for calculation. The estimation of flow rate was made using a calculation of the cross section and velocity using a new method to estimate velocity from cross section and water level values based upon the modified Manning equation. The estimation of total nitrogen concentration was calculated using EC and water level values or flow rate. As a result, the annual total nitrogen load at Kashiwara, Fujii, Itahigashi, Hota, Shintatsuta, Nukatabetakabashi, and Kamihanda stations and the Nara sewage treatment plant were estimated to be 1856, 1793, 751, 498, 260, 188, 83 and 481t/year in 2011. The amounts of total nitrogen load from two sewage treatment plants reached 900t/year, about 45% of those at the Yamato River basin. The annual total nitrogen load at Kashiwara Station under flood conditions with over 24m3/sec of flow rate and excluding flood conditions were calculated to be 835 and 1021t/year in 2011. The annual total nitrogen load at Fujii Station was calculated to be 1013t/year under flood conditions with over 22m3/sec of flow rate and excluding flood conditions to be 780t/year in 2011.

  15. GEOTECHNICAL HAZARD ANALYSIS OF RIVER EMBANKMENT OF BANGLADESH AND ITS PROTECTABILITY Download Article

    Md. Wasif Zaman, Tansir Zaman Asik, Md. Yousuf Rumi and H. M. Shahin
    • Article Type: Research Article
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    • Pages (2050-2057)
    • No of Download = 1043

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    Bangladesh has a long artificial river embankment, developed mainly for the protection of its inhabitants and resources from disastrous flash floods, tidal water, cyclone surges, river currents and others. This process increases erosion of embankments and water turbidity which bring the concerned sediments from alluvial land to the inland sides and river bed that further increase vertical soil accommodation and decrease the water depth. In this research geotechnical hazard analysis has been conducted based on the statistical riverine data and flood occurrence information, obtained from various recognized institutions and secondary literatures and scientific investigation of soil structural failures from field survey. The soil characteristics and existing conditions of the embankments of the three big rivers of Bangladesh - the Ganges, the Meghna, and the Brahmaputra-Jamuna, have been investigated. The research also includes the reasons behind the failure of different embankments that were happened in last decades. A design methodology has been proposed to make these embankments more durable and to improve the strength using a pre-designed methodological case study.

  16. SEDIMENT IMPROVEMENT MATERIALS COMPARISON  APPLIED TO EUTROPHICATED SEASIDE PARK POND Download Article

    Kazuhito Murakami, Saki Agatsuma and Akiko Inoue-Kohama
    • Article Type: Research Article
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    • Pages (2058-2064)
    • No of Download = 517

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    This study was aimed to analysis the influence on bottom sediment environment by sprinkling shell as regional unused resources. In addition, adsorption isotherm was calculated by culture experiments of bottom sediment material improvement to assess its effect. T-N in pore water showed the low concentration with sprinkling shells as regional unused resources, because NH4-N eluted from sediment into water by the influence of sprinkled CaO. T-P in pore water also showed the low concentration with sprinkling shells, and moreover it was remarkable that in burning-treated system more than in non-treated system. By sprinkling, Ca3(PO4)2 was formed with Ca2+ and PO43- bonding on the shell surface, and PO4-P in the pore water decreased. NH4-N and T-N showed the negative adsorption isotherm, because NH4-N eluted in water by sprinkled bottom sediment improvement materials, and nitrogen in the pore water decreased. For T-P and PO4-P, all bottom sediment improvement materials showed positive adsorption effects. CRM treatment using CaO showed the highest effect.

  17. A NEW LABORATORY MODEL OF A SLAKING CHAMBER TO PREDICT THE STABILITY OF ON-SITE COAL MINE SPOILS Download Article

    Chaminda Gallage, Golam Mostofa, David Vosolo and Jay Rajapakse
    • Article Type: Research Article
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    • Pages (2065-2070)
    • No of Download = 640

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    Slope failures of spoil piles pose a significant safety risk in open-cut strip mining due to slaking over time due to overburden pressure and water saturation. Most spoil pile failures occur when the pit has been previously filled with water and then subsequently dewatered. It is important to understand how the mechanical properties of base spoil material are affected by slaking when designing safe spoil pile slope angles, heights, and dewatering rates. A new laboratory slaking chamber (360mm ID, 400mm high with 20mm wall thickness) has been designed and constructed to accommodate approximately 60 kg of spoil (unit weight, 18 kN/m3) and a simulated overburden pressure of 1000 kPa. Consolidation of the spoil can be measured through a linear variable differential transformer (LVDT) attached to the system. Using this apparatus, a fresh spoil material collected from a coal mine in Brown Basin Coalfield of Queensland, Australia was subjected to high overburden pressure (0 – 900 kPa) under saturated condition and maintained over a period of time (0 – 6 months) allowing the material to slake and successfully tested for classification, permeability, and strength properties. Results suggested that the slaking of saturated coal mine spoil increase with overburden pressure and the time duration over which the overburden pressure was maintained. Shear strength and permeability of spoil decreased with increase in spoil slaking.

  18. POSSIBILITY FOR SOLIDIFICATION OF PEATY SOIL BY USING MICROBES Download Article

    Atsuko Sato, Satoru Kawasaki, Toshiro Hata and Toshihiro Hayashi
    • Article Type: Research Article
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    • Pages (2071-2076)
    • No of Download = 689

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    Peaty soil is widely distributed in Hokkaido. Untreated, it is too soft for use as a civil engineering material. Soil solidification improvement technologies that harness the metabolism of microbes in soil have recently been gaining attention. Such research and development has proceeded within and beyond Japan. The researchers investigated a technology for peat solidification that harnesses the ability of microbes inhabiting the soil of construction sites to precipitate calcium carbonate, and consideration was given to solidifying peaty soil by harnessing the ability of those microbes. Focusing on the urease activity of microbes, which has an influence on solidification of peaty soil, a soil solidification test, in which the metabolism of microbes was utilized, and an experiment, in which the degree of solidification of peaty soil was tested, were done by using peaty soil samples from Hokkaido. The two experiments found the following. 1) Microbes that have urease activity inhabit the peaty soil of Hokkaido. 2) It is possible to solidify peaty soil by enhancing the urease activity of these microbes. 3) It is possible to evaluate the degree of urease activity in peaty soil by measuring its electric conductivity.

  19. STUDY OF SPH SIMULATION ON TUNNEL FACE COLLAPSE Download Article

    Tsutomu Matsuo, Kunio Mori, Nobutaka Hiraoka, Mengxia Sun, Ha H.Bui and Ryoichi Fukagawa
    • Article Type: Research Article
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    • Pages (2077-2082)
    • No of Download = 738

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    Maintenance measures for tunnel portal zones have attracted increasing interest owing to the increased collapse risk of slopes by severe torrential rain and inland earthquakes in Japan in recent years. However, these large-scale collapse behaviours cannot be simulated by finite difference method (FDM) analysis. In this study, we applied the smoothed particle hydrodynamics (SPH) method to analyse the collapse behaviour of the tunnel face under construction and the effect of the stabilization method. First, we simulated the collapse behaviour at the tunnel portal zone by two-dimensional SPH simulation and compared it with an aluminium-bar experiment, and we showed that the SPH method is effective to model the overall tendency of the large deformation and the collapse behaviour in the experiments. Second, we simulated the collapse behaviour using the SPH method in the real tunnel portal zone collapse and provided a restraint result for collapse using facebolts. Therefore, we demonstrated that the SPH method is an effective technique to evaluate reinforcement measures.

  20. SOIL AND BACKFILL MATERIAL OF ENVIRONMENTAL FRIENDLY THERMAL PROPERTIES Download Article

    Muawia A Dafalla and Abdallah. Samman
    • Article Type: Research Article
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    • Pages (2083-2087)
    • No of Download = 1008

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    The rate at which heat is transferred through the earth is a phenomenon that affects the environment. In arid and semi-arid areas environmental weather changes show temperature ranges of more than 15 degrees. The nature of substrata or subsurface soil determines the temperature variations at any given time of the day. Gain and release of heat are generally slow but mainly dependant on the constituents of the ground. It is believed that clay content of backfill material can be a significant factor to control temperature during evening and early morning times. Investigations of heat gain and release including temperature changes were studied for soils commonly used. Range of optimum clay content associated with convenient evening weather will are highlighted.

  21. EFFECT OF THE SOIL MOISTURE DISTRIBUTION AFTER RAINFALL ON SEISMIC STABILITY OF EMBANKMENT SLOPE Download Article

    Koichi Sumi, Nobutaka Hiraoka, Masamitsu Fujimoto and Ryoichi Fukagawa
    • Article Type: Research Article
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    • Pages (2088-2093)
    • No of Download = 766

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    Recent studies of sediment disasters have indicated that slope failure due to earthquakes was affected by precipitation before the earthquake. Here, we focus on the effects of variation in soil moisture conditions due to antecedent rainfall on slope failure due to earthquakes. To clarify the relationship between the volumetric water content of soil with elapsed time after rainfall and the scale of slope failure, we conducted a series of vibration loading experiments under different soil moisture conditions. In the experiments, ‘rainfall’ was applied to the model slope using an artificial rain simulator, and the model slope was subjected to seismic wave loading using a shaking table. Soil moisture and laser displacement sensors were used to measure the volumetric water content of soil and displacement of the slope, respectively. The results indicated that the top of slope collapsed and sliding failure occurred when the volumetric water content of the soil was low. The crest of the model slope settled considerably without eroding the sliding surface when the volumetric water content of soil was high. Our study indicated that the soil moisture distribution has a significant influence on the scale of slope failure.

  22. A METHOD TO JUDGE SLOPE FAILURES USING SOIL MOISTURE CHARACTERISTICS Download Article

    Tetsuya Iida, Masamitsu Fujimoto, Nobuyuki Kumakura, Daisuke Takasaki, Nobutaka Hiraoka and Ryoichi Fukagawa
    • Article Type: Research Article
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    • Pages (2094-2100)
    • No of Download = 799

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    Slope failures often occur in Japan, and they frequently result from an increase in the moisture content of the soil. Thus, it is important to consider soil water content. In this study, we carried out a series of laboratory experiments to evaluate changes in soil moisture during rainfall. In the experiments, we constructed a model slope in which we installed 10 soil moisture sensors. The results indicated that the volumetric water content in the slope increased with rainfall, and the increments in volumetric water content were affected by the intensity of the rainfall. Then, using the experimental results, we developed a technique for judging slope failure risk based on absolute values of volumetric water content and rainfall characteristics. Our proposed method will be useful in judging the risk of slope failure because the criteria for the method are based not only on the precipitation but also on the soil moisture in-situ.

  23. EXPERIMETAL MEASUREMENT OF SOIL-PRESTRESSED FOUNDATION INTERACTION Download Article

    Radim Cajka, Petr Mynarcik and Jana labudkova
    • Article Type: Research Article
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    • Pages (2101-2108)
    • No of Download = 738

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    Several experimental measurements of reinforced concrete slab – subsoil interaction are compared with numerical analysis of shallow foundation by means of FEM.  At the Faculty of Civil Engineering VSB – Technical University of Ostrava testing device was constructed so that the phenomena of soil – foundation interaction could be experimentally investigated and compared with numerical models. The experimental model was designed as a cutout of prestressed foundation slab-on-ground and the static load test was conceived as a simulation of local loading of a square shape column. During the static load test, measurements focused on observation of horizontal deformations, tension inside the slab and on the contact surface between foundation structure and subsoil. The described static load test was part of a series of experiments realized at the Faculty of Civil Engineering, VSB –Technical university of Ostrava.

  24. CHARACTERISTICS OF RAIN INFILTRATION IN SOIL LAYERS ON THE HILLSLOPE BEHIND IMPORTANT CULTURAL ASSET Download Article

    Yuuki Arimitsu, Masamitsu Fujimoto, Nobutaka Hiraoka, Toru Danjo, Yuko Ishida and Ryoichi Fukagawa6
    • Article Type: Research Article
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    • Pages (2109-2115)
    • No of Download = 629

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    Recently, slope failures have occurred due an increase of heavy rainfall and typhoon events. As typical examples, sediment disasters have occurred frequently at Kiyomizu-dera Temple, including debris flows in 1972 and shallow slope failures in 1999 and 2013. Kiyomizu-dera temple is a UNESCO World Heritage Site, and one of the Historic Monuments of Ancient Kyoto, Japan.  An increase in shear stress and decrease in shear strength due to infiltration of rainwater led to slope failures. In this study, subsurface water movements were investigated by measuring pore water pressure changes and hydraulic gradients during rainfall events to prevent damage to important cultural assets by natural disasters. Saturation was found to occur after very small rainfall events, regardless of soil moisture conditions. Although subsurface water normally flows from upper to lower areas of the slope, water movements from the bedrock to the soil layer were observed during rainfall events, suggesting the existence of potentially hazardous slope failure conditions.