Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering
Online ISSN : 1884-7242
Print ISSN : 1882-2789
ISSN-L : 1882-2789
Volume 2008 , Issue 255
Showing 1-16 articles out of 16 articles from the selected issue
  • Mandula, Kunio HATTORI, Hidehiko OGATA, Isamu NATSUKA, Shiwen GUO
    2008 Volume 2008 Issue 255 Pages 227-234,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    This paper discusses the utility of simple abrasion test equipment that was designed on the basis of Chinese National Standards GB/T 16926-1997, to measure the abrasion resistance of pavement concrete. Main characteristics of this equipment are smaller number of rotating balls, lower speed, and variable pressure (0-120N). To access the practicability of the equipment, abrasion tests were conducted on mortar and concrete specimens cured under different conditions and at different curing age. Results confirmed the performance and importance of measuring the abrasion resistance of pavement concrete by trundle abrasion method.
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  • Katsuya SHIRATORI, Yuji YAMASHITA, Yasuhisa ADACHI
    2008 Volume 2008 Issue 255 Pages 235-240,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    Surface charge property of Toyoura sand prepared with two different ways and the capture of kaolinite particle of the column packed with those two kinds of sand were analyzed focusing the presence of surface deposits in order to clarify the surface properties of Toyoura sand as collector grains. Scanning electron microscopy (SEM) revealed that the deposits on the surface of Toyoura sand were removed by ultcasonication. Surface charge property of Toyoura sand before and after ultrasonication was measured by streaming potential method as functions of pH and ionic strength. Zeta potential of bare sand became higher below pH 7 and lower above pH 7 than those values of the sand covered with surface deposits. Electrophoretic mobility of the removed deposits was measured as functions of pH and ionic strength under ultramicroscopy. The zeta potential of the sand covered with deposits was found not to be the simple sum of surface deposits and bare sand The rate of particle capture through of the column packed with ultrasonicated sand turned out to be lower than the value of untreated one.
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  • Mandula, Kunio HATTORI, Hidehiko OGATA
    2008 Volume 2008 Issue 255 Pages 241-248,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    Based on the climate characteristics and concrete pavements in Inner Mongolia of China the objective of this study is to estimate the practicality of using fly ash in concrete pavements which is discharged from coal fire power stations in Inner Mongolia Abrasion depth was measured after freezing and thawing test and it was indicated that the abrasion was not influenced by fly ash replacement ratio in concrete because of the better abrasion resistance of the surface coarse aggregates after freezing-thawing test. Chinese fly ash is available for general use up to 50% replacement on standard concrete pavement in China.
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  • Emi TAKEYAMA, Yasuaki KUKI
    2008 Volume 2008 Issue 255 Pages 249-255,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    This study aims to development the animal attack control measure from a view of rural engineering. This paper aims to provide the local agricultural characteristics and animal damage type in the area where the physical prevention has priority as an animal attack control measure. 43 municipalities of Wakayama prefecture are classified by choice of animal control measure into 3 types, with result of questionnaire research. As a result, the characteristics of the area where the physical prevention has priority are followed;
    1) Ratio of damaged area by wild boar is high.
    2) Ratio of uncultivated farmland area is high.
    3) Cultivated farmland area per a farmer is small.
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  • Koji SAI, Masayoshi HARADA, Kazuaki HIRAMATSU, Makito MORI
    2008 Volume 2008 Issue 255 Pages 257-266,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    A 3-dimensional eco-hydrodynamic model was developed to analyze the behavior of dissolved oxygen (DO) in Lake Togo, located in Tottori prefecture in Japan. Based on the observed data, the model simulated the behavior of water qualities in the lake. The results show that the model approximately reproduced the temporal and spatial variations of the water qualities observed in the field. It was concluded that the model could be applied to analysis of the lake's water environment. To investigate the occurrence mechanism of anoxic water, numerical experiments were carried out using the model. As a result, DO consumption by the bottom sediment exceeded the physical and biological supply of DO to the bottom water at the deepest point of the lake under wind velocity conditions of 3 m/s. Therefore, anoxic water appeared at the bottom layer in the southern part of the lake. Under wind velocity conditions of 6 m/s, the bottom water maintained high DO concentration because the physical supply of DO increased due to vertical circulation caused by strong wind stress.
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  • Masumi KORIYAMA, Masahiro SEGUCHI, Tetsuhiro ISHITANI
    2008 Volume 2008 Issue 255 Pages 267-275,a1
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    In the present study, the occurrence mechanism of hypoxic water that occurs frequently in the interior western parts of the Ariake Sea was investigated by the two-layer box model on the base of field observation data and Saga Prefecture research data in 1972-2000.
    As a result, seasonal variations of advection velocity, vertical diffusion coefficient and biochemical oxygen-consumption rate in the study area were clarified. The physical process (i. e. advection and vertical diffusion) and biochemical oxygen-consumption process, which related to the temporal variation of dissolved oxygen (DO) concentration in lower layer box, were evaluated. The analytical results showed that vertical diffusion and biochemical oxygen-consumption contribute greatly to the temporal variation of DO concentration in lower layer box during summer season, and 83% of DO was supplied to lower layer box by vertical diffusion. In addition, it was considered that the occurrence of hypoxic water in the study area during summer season was caused by the fact that the biochemical oxygen consumption in the bottom layer was more than DO supply from the surface layer to the bottom one due to vertical diffusion.
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  • Kousuke WAKASUGI, Shinsaku FUJIMORI
    2008 Volume 2008 Issue 255 Pages 277-282,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    The agglomeration of farm fields and the establishment of large-scale rotation crop systems, involving e. g. paddy rice, soybean, and wheat, is a current requirement for Japanese agriculture. The low-cost, labor-saving cropping technology, a prerequisite for this development, may be hampered by moisture damage or drought. As a promising method to avoid such problems, a sloping subsoil and field surface was made using a laser-controlled plough and leveler for studying the effects of the slope on paddy water drainage and flooding rates, determining an optimum slope, and examining soil loss. The sloping field proved to be effective for accelerating drainage by increasing the drain flow rate. The technology contributes to preventing moisture damage and to reducing irrigation time, which suppresses moisture damage around the water intake. The slope caused no surface erosion. A slope of 1‰ was proper in terms of drain and irrigation facilitator, soil loss, and construction times.
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  • Nobuo FUJITA, Yoshiyuki MOHRI, Tadatsugu TANAKA
    2008 Volume 2008 Issue 255 Pages 283-294,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    An outlet conduit is installed underneath a reservoir embankment. The overage reservoir embankment has often deteriorated contact pressure between the outlet conduit and the fill, and involved latent flow path. When a heavy rain or an earthquake damages embankment by piping failure, it is inferred that these weak points around outlet conduit is a main factor.
    In this paper, model tests and numerical analyses were conducted, focusing a seepage condition and a making process of flow path around outlet conduit, to confirm the effective outlet conduit structure to restrain from piping.
    Results are summarized as follows:(1) Numerical analyses agree well with the experiments when a coefficient of permeability around outlet conduit area is assigned higher than the other area.(2) Cut-off collar takes effect to raise a critical hydraulic gradient around a conduit and it is inferred that the movement of soil particles along a conduit rather than the length of seepage path influences piping behavior.(3) The outlet conduit having flexible joints fits to the gap caused by making flow path or local settlement of ground, therefore it is more resistant to piping failure than the rigid conduit without flexible joints.
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  • Tatsuo NAKA, Masahiko SHIMAZAKI, Hiroyuki TARUYA
    2008 Volume 2008 Issue 255 Pages 295-301,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    The fine sediment removal efficiency of a seepage settling basin built to control outflow sediment was investigated on-site. The target sediments were suspended sediment and microscopic load from upland fields.
    In the seepage settling basin work desingned by this study, bed load is controlled by a vortex tube sand trap in the inlet canal and suspended load by underdrain filter material and improved gravity precipitation in the settling basin. The hydraulic design concept, structural components and construction of the settling basin are described.
    It was found that suspended load is proportional to surface outflow rate from the upland field in terms of magnitude and rain. The sediment removal efficiency of the vortex tube sand trap for the period was 57%-100%.
    The outflow of fine sediment is proportional to the second power of the runoff flow rate from the upland. This characteristic corresponds to the findings on wash load by river engineering. The effect of an underdrain was also studied through analysis of experimental data. The density of the underdrain correlates with the inflow density.
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  • Toru SASAKI, Hidenori AKASAKA, Ryoko SUZUKI, Katsumi FUJII
    2008 Volume 2008 Issue 255 Pages 303-308,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    The objective of this research is to check the possibility of utilizing unused biomass to farm land for improving soil quality. This research was performed to investigate the changes of soil physical properties such as three-phase composition and soil hardness by incorporation of organic material, namely, saw dust and rice straw into volcanic ash soil, Andisol. We did compaction test, after that, we experimented three phase composition and soil hardness. In case of three-phase composition, gas phase in sample increased as mixing ratio of saw dust and rice straw increased. Mixing effect of rice straw to three-phase composition was more significant than that of saw dust on the basis of the same unit volume of mixing materials. Soil hardness decreased with increasing mixing ratio. We discussed the reason of the incorporation characteristics by the relationship between soil hardness, mixing ratio and dry bulk density, and concluded it was caused by increase of pores. In addition, it proved that soil hardness was also influenced by water content of soil.
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  • Wataru KAKINO, Masakazu MIZUTANI
    2008 Volume 2008 Issue 255 Pages 309-312,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    In order to grasp distribution characteristics of Yokohamashijiragai (Inversiunio jokohamensis), field investigation was carried out in a hill-bottom valley during the non-irrigation period (March) in Tochigi prefecture. The results obtained from the investigation were as follows: 1) the results of correlation analysis showed that the mussel density was positively correlated to the coverage of gravel, however negatively to the bottom softness, the coverage of bedrock and of silt with a significant level of p<0.01, 2) population density in the east side ditch was higher than that in the west side ditch, probably because the gravelly bottom was dominant in the former, and 3) Young and old individuals were also found in the east ditch. The above results implied that the east side ditch holds a better breeding ground due to gravel sediment. In addition, their absence in the west side ditch may be due to the drought in early autumn and the dominance of bedrock.
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  • Shinichi TAKESHITA, Haruhiko HORINO, Toru MITSUNO, Takao NAKAGIRI
    2008 Volume 2008 Issue 255 Pages 313-320,a2
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    The characteristics of wind behavior and thermal distribution in the Kishiwada area along Osaka Bay were surveyed through the observation of temperature and wind over the area. In this area, rural and urban landuse is intricately mixed. In this study, the seasonal and regional heterogeneity of water was considered. Firstly, it was confirmed that sea breeze from the north in the daytime and land breeze from the south-east in the nighttime were superior in this area on fine weather days when the gradient of atmospheric pressure is gentle. Then, the whole study area was divided into three (“urban”, “rural”, and “mixed”) areas according to the landuse dominance and the mean temperature in each area was compared by period (irrigation and non-irrigation). The result showed that the difference of the mean temperature among these areas in the irrigation period was wider than in the non-irrigation period and the mean temperature in the rural area, where there are a lot of farmland and irrigation ponds, was the lowest in both the daytime and the nightime. It was also indicated that in the daytime on the days with the prevailing sea breeze, the mean temperature in the mixed area was rather higher than in the coastal urban area, though the mixed area is on the inland side of the coastal urban area.
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  • Hirofumi KAKUDO, Masato KIJI, Aya SUETSUGU, Takanori KUSAKABE
    2008 Volume 2008 Issue 255 Pages 321-327,a3
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    One of environmental issues of an irrigation tank as one of closed water areas is water pollution such as organic pollution and eutrophication that is induced by inflow of domestic wastewater from the catchment area. A development of reasonable technique to improve water quality is required in order to conserve water environment, landscape, and habitats of irrigation tanks, because irrigation tanks may provide an open space to take a rest for residents generally.
    The objective of this study was to evaluate a performance of the Thin Layers of Soil Method for a technique to improve water quality of an irrigation tank. The Thin Layers of Soil Method was developed to treat drainage from kitchen and its effectiveness was illustrated by several experiments. In this paper, indicators to evaluate the performance of the method for an irrigation tank were COD concentration and T-N and T-P concentration as typical nutritional salts.
    As the results of experiments done for several months including summer at two irrigation tanks in which water quality parameter such as COD, T-N, and T-P differed from each other, removal ratio of COD was about 38 percent and removal ratio of T-P was about 34 percent, although T-N removal were not entirely clear. For an improvement of the method to adopt an irrigation tank, to maintain detention time of raw water in the installation and to keep anaerobic environment in the installation were needed.
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  • Atsushi NAMIHIRA, Kyoji TAKAKI, Masahiro GOTO, Hiroyasu KOBAYASHI
    2008 Volume 2008 Issue 255 Pages 329-337,a3
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
    There are some cases in which the downstream apron is made to be stairs shape whenthe river bed downstream of headworks degrades. The apron with such shape, called stepped ground sill, is demanded to dissipate the energy of flow securely and to prevent the local scour downstream of itself. In this research, characteristic of fluid forces on stepped ground sill with 2 steps is investigated by hydraulic model testand numerical model test. And then, it is clarified that the peak of the fluid forces on the horizontal plane in each steps relatively becomes small with shape which negative pressure is not caused on the horizontal plane in each steps if when the total height of the stepped ground sill is constant. Additionally, it is clarified that the index of the condition that negative pressure is not caused on the horizontal plane in each steps are the ratio of total head to critical depth of flow before falling, and the inclination of central step.
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  • [in Japanese], [in Japanese], [in Japanese]
    2008 Volume 2008 Issue 255 Pages 339-340,a3
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    2008 Volume 2008 Issue 255 Pages 341-342,a3
    Published: June 25, 2008
    Released: August 11, 2011
    JOURNALS FREE ACCESS
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