Journal of the Japan Society of Erosion Control Engineering
Online ISSN : 2187-4654
Print ISSN : 0286-8385
ISSN-L : 0286-8385
Volume 73, Issue 2
Displaying 1-14 of 14 articles from this issue
Pictorials (Series Measure)
General Remark
Original Article
  • BAOYINARIBIJIHU, Yoshiharu ISHIKAWA, Katsushige SHIRAKI, Hiroki HARAD ...
    2020 Volume 73 Issue 2 Pages 3-13
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    Although the drilling resistance tests and dynamic pin penetration tests were commonly used for measuring deteriorated thickness of woods, there are some faults for inspection of in-situ wooden structures. We tried to develop a simple and high accurate measuring apparatus for deteriorated thickness by static penetration using 7 types steel pins. Firstly, we developed a static penetration test apparatus with electric motor operation and measured penetration thickness and penetration force as it penetrated wood with constant penetration speed. The required penetration forces for measuring by static penetration tests were analyzed for measuring the deteriorated thickness using 7 types steel pins compared with the deteriorated thicknesses which were obtained by the drilling resistance tests. The accuracy of measurement of the deteriorated thicknesses were examined for every 7 types steel pins. Secondary, we developed a simple static penetration test apparatus with a penetration force measurement device to measure penetration thickness which can be used even in water. The measurements of deteriorated thickness were conducted by three persons using the simple static penetration test apparatus. The tests results indicated that the wedge-shaped steel pin with 3 mm in diameter can measure deteriorated thickness with the highest accuracy with the simple static penetration test apparatus. The buckling phenomena were observed in measurement by using steel pins with 2 mm in diameter. The investigation revealed that the wedge-shaped steel pin with 3 mm in diameter is mostly suitable for the simple static penetration test apparatus to measure deteriorated thickness for in situ wooden structure.

    Download PDF (1017K)
Technical Paper
  • Yoji SAWA, Kiichiro OGAWA, Michiya IRASAWA
    2020 Volume 73 Issue 2 Pages 14-23
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    Niigata prefecture in Central Japan, the first auxiliary erosion and sediment control project was started at Hikagesawa, Bannai river in 1921. This river is a tributary of Yashiro river included in the Seki river system that flows through Myoko city. Afterwards, construction for erosion and sediment control in Kamakurasawa river, which is a tributary of Uono river included in the Shinano river system, was carried out from 1927. However, the historical background of construction in both facilities has not been investigated clearly. Therefore, the author performed document and facility investigation regarding Hikagesawa, Bannai river and Kamakurasawa river, and then clarified the historical background of construction. As a result, we found that Maruo Ikeda and Masao Akagi, who are famous Japanese engineers specializing in erosion and sediment control technology, led the project and introduced the latest technology at that time in the early phase of erosion and sediment control project in Niigata prefecture. Both facilities have strong influence on subsequent facility plans for erosion and sediment control in Niigata prefecture. In this study, we revealed not only the historical background of construction of facilities for erosion and sediment control at Hikagesawa, Bannai river and Kamakurasawa river but also the technological features of constructed facilities for erosion and sediment control.

    Download PDF (1701K)
General Review
  • Mutsuo KAWAI
    2020 Volume 73 Issue 2 Pages 24-33
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    Sabo (Erosion Control) designated areas are designated by the Minister of Land, Infrastructure and Transport pursuant to Article 2 of the Sabo (Erosion Control) Act (Act No. 29 of 1897) for the purpose of erosion control and flood defense. The authority for restriction or prohibition in the said areas pertaining to actions that compromise the purpose of the designation rests principally with prefectural governors pursuant to paragraph 1 of Article 4 of the same Act and restriction or prohibition needs to be provided for in prefectural ordinances pursuant to Article 3 of the Cabinet Order for Enforcement of the Sabo Act (Cabinet Order No. 362 of 1897). In case interests of more than one prefecture are concerned, the same Minister himself can exercise the said authority pursuant to paragraph 2 of the same Article, but there has been no ministerial exercise of the authority up until now. Erosion control is a matter of national interest whether the Minister itself is prepared to exercise the authority or not. In this light a comparative analysis of relevant prefectural ordinances set out in this paper is expected to be an indispensable reference that could attract broad attention.

    Download PDF (903K)
Research Notes
  • Kazuya FUNAKOSHI, Satomi KAKUTA, Wakana YAGI, Masashi TAI, Masayuki MA ...
    2020 Volume 73 Issue 2 Pages 34-41
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    In this study, we tested a method to detect landslide areas automatically by using pre-and post-disaster optical satellite images. Asakura City and Toho Village in Fukuoka Prefecture as well as Hita City in Oita Prefecture were selected as test sites since many landslide disasters occurred after heavy rainfall in Northern Kyushu District in July 2017. The method utilizes a constellation of satellites equipped with high resolution optical sensors, which acquired high frequency pre-and post-disaster images. For early detection of landslide disasters, a change detection method (detect landslide area by using the change of the NDVI value between pre-and post-disaster) and a deep learning detection method (detect landslide areas using post-disaster images) was examined. And from the test sites analysis, the logical product (AND condition) which combines the two methods was the most suitable. To verify the validity, we applied the method to Iburi eastern district in Hokkaido where many landslide occurred by a large earthquake. Results show that the user accuracy was 68.1%, while the producer accuracy was 69.7%. Furthermore, analysis revealed that the detection error rate based on the land use classification was low in hillslopes covered with vegetation. However, the detection error rate was high in cultivated areas with exposed soil after harvest, and water areas with high turbidity. The study results indicate that the landslide detection method, and high frequency pre-and post-disaster optical satellite images are effective for early detection of landslide disasters that occur in wide areas at hillslopes covered with vegetation.

    Download PDF (1616K)
  • Yasuhiro NOMURA, Soichi KAIHARA, Hiroaki TAKEMOTO, Taro UCHIDA, Hiroak ...
    2020 Volume 73 Issue 2 Pages 42-47
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    Early-warning systems for natural disasters are important tools for disaster risk reduction and for achieving sustainable development and livelihoods. Principal methodology of early warning systems is to set a criterion for occurrences of debris flows or multiple slope failures based on several rainfall indices (60-min cumulative rainfall and soil-water index (SWI)) in all 5 km grid meshes over Japan. Parameters of the tank model for SWI are unified as those of granite around the nation. In this paper, deferent parameters proposed by Uchida et al (2016) based on the area's geological features are tested for SWI. Modification accuracy of early-warning is examined in model areas. The result shows that the SWI values with tested parameters are smaller than the original ones by approximately 20-30%. Although the relative relationship between rainfall data and criterion stays unchanged, the variations of SWI values are reduced significantly. This shows that there are possibilities to limit the range of SWI values of critical lines for sediment disasters on the basis of geological features.

    Download PDF (1218K)
Technical Note
  • Norio HARADA, Yoshifumi SATOFUKA, Takahisa MIZUYAMA
    2020 Volume 73 Issue 2 Pages 48-54
    Published: July 15, 2020
    Released on J-STAGE: July 15, 2021
    JOURNAL OPEN ACCESS

    In 2019, the maintenance and management procedures in place for Sabo facilities, including the maintenance and post-maintenance phases, were reviewed. We proposed a quantitative method for evaluating the soundness of Sabo facilities based on maintenance methods used for other structures. However, a maintenance method that takes into account the costs incurred over the life cycle of Sabo facilities is urgently needed. We then analyzed the degree of deterioration of Sabo facilities according to previous inspection reports. We present a method for developing Sabo maintenance management plans with consideration of life cycle costs.

    Download PDF (1234K)
Information from the Field
Series Measure
Book Review
Memorial Writing
feedback
Top