• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.325-332
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• 2016

Configuring excavator attachments and engine sizes is the prerequisite for appropriate excavator assignment. Existing experience based configuration practice is lack of scientific rational because many variables (e.g., equipment motion data, soil and rock type and condition, equipment's engineering dimension along with bucket properties, job and management conditions etc.) should be considered simultaneously and timely fashion. This paper presents a new excavator configuration searching method that identifies the most favorable excavator configuration (i.e., the optimal set of excavator's maximum digging height and bucket size) to complement these existing practices. The method coded by using MATLAB identifies an optimal excavator configuration by considering those variables causing the variability of productivity. A case study is presented to demonstrate and to verify the system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.255-265
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• 1991

In order to find the excavating performance of water-jet nozzle on the sand, the authors were carried out the excavating experiment with the model nozzles which were semi circular sectioned nozzles and rectangular nozzle in water tank. The results were as follows. 1) Excavating maximum depth and width on the sand by the water jet were straightly increased in proportion to the velocity of water jet and the section area of nozzle, and that, by the nozzle distance from the excavating point on the sand, the depth was decreased, while the width was increased straightly. 2) Rectangular nozzle which the thick of hole is 1mm, was a little bit better than the circular nozzle of the same sectioned area on the excavating performance. 3) Empirical equations between the velocity of water jet, the distance of nozzle, and the maximum excavating depth and width by angle of nozzle were expressed as linear, they were as follows on the 45$^{\circ}$ angle of the rectangular nozzle(1$\times$12mm); D=0.0093V sub(0)-0.23H+5.7. W=0.0147V sub(0)+1.06H+10.2. where, D is the maximum excavating depth(cm), W is the maximum excavation width(cm), V sub(0) is the velocity of water jet(cm/s); 926$\leq$V sub(0)$\leq$1504, H is the distance(cm) from nozzle tip to water-jetted point on the surface of sand.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.266-277
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• 1991

To catch the surf clam, Mactra chinensis, in sand bottom using the excavating performance of water jet, the authors had constructed the experimental hydraulic jet dredge by the result of water tank experiment of previous report, and also were carried out the field experiments in the surf clam fishing ground near Kunsan, Korea from 5th to 30th of October, 1990. The results obtained are as follows. 1) Excavating depth was more than 10~11cm at the 1500cm/s water-jet velocity in the fine sand and muddy sand. 2) Towing tention was only 105$\pm$5kg in the 6.7cm/s towing speed. 3) Average catch amount per unit towing area was 0.42kg/m super(2) and it was 1.2~1.6 times comparing on the conventional dredge. 4) Experimental hydraulic jet dredge did not nearly brake the surf clam. 5) Turbidity variation by the water jet of dredge was not serious in the fishing ground; On the surface, when the depth is more than 5.2m, turbidity variation was not found at all, and on the 3m layer above the bottom, turbidity variations was increased 9~11ppm at 1m backward from the dredge, but it was gradually decrease, and it was nearly not at 9m backward from the dredge.