著者

大塚 尚寛

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.138, no.5, pp.60-69, 2022-05-31 (Released:2022-05-13)

参考文献数

38

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Aggregate is important as a basic material that supports Japan's industrial economy, along with steel, cement, wood, and non-ferrous metals as construction materials for civil engineering and construction. After the Great East Japan Earthquake, the importance of aggregate as a basic material was reaffirmed, and the demand for aggregate is currently in a slight increase or leveling off, and the annual production has been around 380 million tons. In this review, overviewing the transition of aggregate production in Japan from the viewpoint of aggregate resources, the current issues and future prospects are explained. It mentions the shift to mining method in harmony with the environment to enable “sustainable development” on the premise of coexistence with the region, which is an important issue in the mining and production of aggregate. Then, it will be described that trends such as the construction of smart mining system that utilize ICT, IoT, AI, etc. with the aim of responding to labor shortages due to the declining birthrate, aging population, and the advent of a declining population.

著者

大塚 尚寛 小林 良二

出版者

一般社団法人 資源・素材学会

雑誌

日本鉱業会誌 (ISSN:03694194)

巻号頁・発行日

vol.98, no.1127, pp.1-6, 1982-01-25 (Released:2011-07-13)

参考文献数

10

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In order to determine the fracture toughness of various rocks, the splitting tests under the stiff-load are undertaken on eight kinds of rocks, namely OGINO tuff, KIMACHI sandstone, IZUMI sandstone, EMOCHI andesite, INADA granite, fine grained AKIYOSHI marble, medium grained AKIYOSHI marble and TOHOKU marble.The rock specimens (200mm×150mm×20mm) in which have a slot are prepared in this test. The crack initiation and the process of crack propagation are studied by the measurement of splitting load, crack opening displacement and crack length. The values of fracture toughness KIC of various rock specimens are determined with the compliance method, and the relationships between fracture toughness and mechanical properties are investigated.The main results obtained in this studies are as follows;(1) As a result in this test, it is seen that the fracture behaviours of rock specimens are divided into two groups. That is, the fracture crack of rock specimens of one group initiates after the maximum load point in the splitting load-crack opening displacement curve and propagates in a straight line, as OGINO tuff, KIMACHI sandstone, IZUMI sandstone, EMOCHI andesite and INADA granite. The fracture crack of rock specimens of other group initiates at the boundary of grains in rock before the maximum load point and the fracture crack in rock specimens propagateslowly along the boundary, as medium grained AKIYOSHI marble and TOHOKU marble.(2) From the relationship between fracture toughness and mechanical properties of various rocks, it becomes clear that fracture toughness of rocks increases in proportion to compressive strength, tensile strength and shear strength, and that fracture toughness decreases with the porosity of rocks increas.

著者

大塚 尚寛 関本 善則

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.109, no.11, pp.897-902, 1993-11-25 (Released:2011-01-27)

参考文献数

8

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It is considered that land deformation caused by open-cut mining influences on wind system around the quarry. Two case studies were conducted to investigate the change of wind system around the quarry.The results are summarized as follows:(1) Land deformations caused by open-cut mining were simulated with three dimensional computer graphics, and it became possible to forecast the changes of wind direction visually.(2) By use of quantitative formula that showed the relationship between lay of land and wind direction frequency, it became possible to forecast the changes of prevailing wind direction and wind direction frequency quantitatively.(3) It became clear that deforestation according to open-cut mining influenced on increase of wind speed around the quarry.(4) In case A, the ridge of the quarry will be mined, it was forecasted that change of wind system affected on living environment a little.(5) In case B, all over the mountain will be mined-out, it was forecasted that wind system around the quarry was changed widely.