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Volume 3 (1993)
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Volume 3, Issue 12
Displaying 1-6 of 6 articles from this issue
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Ikuko MORISHITA1993 Volume 3 Issue 12 Pages 4-12
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSWhen looking at freshwater ecosystems in global environment, three problems immediately come to mind.
Firstly, when we think about environment in a global sense, we must consider mankind coexisting with other species. However, the purposes of development and coexistence often clash.
Secondly, effects of development often take ten to twenty years to manifest themselves.
Thirdly, cultural differences are sometimes a barrier to international agreement on environmental isues. Clear, fast running water is the cultural standard for clean water in Japan.
Once polluted Japanese streams aud rivers have been restored because this inherent desire for clean water acted as a brake against unrestricted development. Other Asian cultures such as those along the Ganges River and the great rivers of China have different cultural perceptions of rivers, and consequently, these cultures do not provide as strong a brake. In fact, differences in levels of “cultural braking” are often at the heart of failure to resolve environmental problems among different nations.View full abstractDownload PDF (2713K) -
Eiji YANAGISAWA, Takahiro SUGANO1993 Volume 3 Issue 12 Pages 13-20
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSBased on the shear failure mechanism, hydraulic fracturing criteria are studied for the cases of two and three dimensional stress state near a bore hole by using the theory of elasticity. The criteria are written in a form of functions of maximum principal stress, minimum principal stress and soil parameters in UU condition. In order to prove the integrity of the criteria, laboratory tests are performed on compacted cylindrical specimens and cubical specimens using conventional triaxial apparatus and true triaxial apparatus, respectively. According to the situation of the directions of borehole and major principal stress axes, three equations can be derived for three dimensional hydraulic fracturing problems. The shape and direction of fractures are determined by injecting colored water after fracture initiation and it is found that the direction of fractures are perpendicular to the σ3 plane.View full abstractDownload PDF (1467K) -
Mitsuru AIBA, Haruhiko IIZUKA, Shinji HABUKAWA, Noriaki SHIGENAGA, Shu ...1993 Volume 3 Issue 12 Pages 21-34
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe girder-stiffened outlet conduit burned in the concrete gravity dam have been designed as a independent structure by ignoreing the concrete, because it is uncertain that the concrete is filled around the conduit. In this paper, we did FEM-analysises for the conduit, considering it as a independent or is burned in the concrete regarded as a elastic body. As a result, the maximum of circumferencial stress of the conduit which is burned in the concrete was decreased to about 10% of a independent conduit. From the viewpoint of the member forces of the beam, we found that the bending moment was mostly beared by the concrete, and the conduit shared about 20% of the axial force. On the other hand, circumferencial tensile stress was ocured on the concrete, and at the corner it became high value because of stress concentration. But, when taking the bond between the conduit and the concrete into consideration, stress of the conduit was increased and stress of the concrete was decreased at the corner. From this, in one idea of the rational design methods, it is posible that we look upon the conduit as a reinforcing bar.View full abstractDownload PDF (2191K) -
Chikaosa TANIMOTO, Kiyoshi KISHIDA, Taku ANDO1993 Volume 3 Issue 12 Pages 35-44_1
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSState of discontinuities is interpreted through those of recovered core, which cannot provide any information on joint orientation, actual apertures, filling materials and so on. By using Borehole Scanner System (BSS), we can observe discontinuities in the undisturbed condition and obtain more realistic information. There is some difference between obtained core pieces and BSS survey due to their own data acquisition systems. In this paper, we compare obtained core pieces with BSS image in terms of joint spacing and RQD. The result leads to the construction of data base for the use of practical design and supervision.View full abstractDownload PDF (2370K) -
Hirondo TANIZAKI, Tatsuro YAMADA, Tomio WAKASAKI1993 Volume 3 Issue 12 Pages 45-52
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe operation of transportation and placing concrete using a cable crane, on the construction site of a concrete dam project, the work usually requires a long hour operation of repeating monotonous work; thus it is apt to induce a mishap of human error. Also, there is a risk of incident for workmen to accidentally contact with the concrete carrier or bucket and be injured.
In order to solve such problems, and secure the safety of work, whereas improving work efficiency by labor-saving, we have developed an automatic driving system for a Transfer Car and a remote open-close control device for a concrete Bucket. By the use of these innovative device, we have acquired the efficiency more than the conventional method of concrete transportation and bucket placing, while obtaining much improved safety factors on the work.View full abstractDownload PDF (1794K) -
Yosiyuki SIBATA, Tamiharu TASIRO, Katumi TUKAMOTO1993 Volume 3 Issue 12 Pages 53-60
Published: December 15, 1993
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThis equipment was developed in an effort to improve the safety and efficiency of the operation of raising the forms for the upstream and downstream faces of dams being constructed by the RCD Method. Regarding the forms themselves, the unit weight of the forms was reduced by employing a truss structure in the vertical ribs, and the efficiency of the form raising operations was improved by enlarging the size of each form panel in order to increase the amount of work completed in raising each panel, On the other hand, the raising machine consists of a form raising device attached to the front of a forklift base machine. Because this form raising device is designed so that the large size dam forms can be securely gripped at three points, the operations of unbolting, raising and bolting the form panels can be performed safely without a danger of swaying. This equipment is presently being employed with good results on the Miyagase Dam Construction Project.View full abstractDownload PDF (1435K)
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