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Volume 14 (2004)
- Issue 4 Pages 226-
- Issue 3 Pages 147-
- Issue 2 Pages 73-
- Issue 1 Pages 4-
Volume 14, Issue 4
Displaying 1-6 of 6 articles from this issue
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Masayuki MAEHARA, Toshiaki SAITO, Kohkichi KIKUCHI, Takashi KOBAYASHI2004 Volume 14 Issue 4 Pages 226-236
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSBy application of HTLP method (High Thickness-Low Pressure Grouting Method) to consolidation grouting of Ueno Dam, it was confirmed that shortening effect of injection time and contribution to reduction of construction cost were remarkable. In addition, we applied high-thickness cement mixes (it is not HTLP method itself exactly) to execution of curtain grouting of the dam. As a result, it was also confirmed that use of high-thickness cement mixes was effective for promotion of efficiency of curtain grouting. But at the same time, shortening effect of injection time was not recognized when Lugeon value was lager than certain level. Furthermore we confirmed the same phenomenon at O dam and T dam. So we made further study to improve HTLP method, and we propose a new method, HTLF Method (High Thickness-Laminar Flow Grouting Method). This new method is characteristic in using comparatively low pressure which can keep flow laminar.View full abstractDownload PDF (1472K) -
Masahisa OKANO, Fumitaka MATANO, Hiroyuki KATAYAMA, Yoshimitsu TAJIMA, ...2004 Volume 14 Issue 4 Pages 237-249
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESS“Multi -Hole Suction Pipe (MHSP), ” proposed by authors, is one of the Hydrosuction Sediment Removal Systems that utilize the water head difference to discharge sediments accumulated in a reservoir without lowering its water level. In this study, we first improve an existing one-dimensional numerical model so that the model accounts for the pressure loss due to the inflow from suction holes of MHSP and the increase of friction force due to suspended sediments in the pipe flow. Using the model, we examine the hydrodynamic characteristics of MHSP such as effective length of the pipe, which accommodates the sediment transport without blocking the pipe flow with sucked sediments. We next introduce the experimental study carried out by authors to investigate the actual time-varying features of MHSP and show that the improved numerical model reasonably explains these time-varying features of the suction processes as steady state solutions. Finally, we discuss how to apply these features of MHSP, observed in the experiments and predicted by the model, to design the entire system of MHSP.View full abstractDownload PDF (8753K) -
Isao NAGAYAMA2004 Volume 14 Issue 4 Pages 250-256
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSRCD is lean and dry mix of concrete which is compacted by vibrating rollers. Strength of RCD is influenced not only by cementitious material water ratio, but also by compaction density. This paper deals with the factors which have influence on strength of RCD. The result shows that relative strength, which is defined as the rate of measured strength to theoretical strength, is expressed by the linear function of relative density, which is defined as the rate of measured density to theoretical density.View full abstractDownload PDF (1799K) -
Tomoyuki SUZUKI, Josuke KASHIWAI, Yoshihiro YOSHIOKA2004 Volume 14 Issue 4 Pages 257-269
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn order to plan and execute countermeasures for sedimentation problem in an actual dam, it is necessary to make prediction of reservoir sedimentation under the condition of various kinds of countermeasures. A numerical simulation is a useful tool for the prediction. However, for the purpose of getting highly accurate prediction, estimation of the sediment discharge into dam-reservoir is also important. In this paper, we propose an estimation method of non-uniform sediment discharge using actual results of dam reservoir sedimentation. The method includes developing a calculation technique for trap efficiency of fine sediment and systematizing estimation processes of field surveys and data analysis. The validity of this method is confirmed through the case of Sabaishigawa Dam in Nigata Prefecture.View full abstractDownload PDF (3631K) -
Kazuhiro CHAYAMA, Takeshi YAMAUCHI, Yukio TANOUE, Takayuki KUBOTA, Aki ...2004 Volume 14 Issue 4 Pages 270-284
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn recent years, rapid progress has been made in the fields of data processing/transmission and servo-mechanics. These advances have allowed us to develop a tele-operated robot system which can be easily mounted to general-purpose construction machines. The aim of this development has been to improve portability, mountability, applicability and ease-ofoperation of the robot system. Through experiments using models of the robot arms, field experiments using a full-scale robot and cycle time analysis of these experiment results, the following observations were made:
1) Time required for installation of the robot to construction machines can be reduced by accumulating experience,
2) Operators can be familiarized with the system in six hours,
3) Unmanned operation efficiency is around 55% compared to manned operation efficiency under same conditions.
The applicability of the system has now been proved though real-world use at actual disaster recovery works with the unmanned operation efficiency of around 65%. Also, our experience in actual use suggests that;
4) significant performance improvements can be achieved by providing the operator with more visual information.View full abstractDownload PDF (15893K) -
[in Japanese]2004 Volume 14 Issue 4 Pages 285-296
Published: December 15, 2004
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (12179K)
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