| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure and a construction method therefore suitable for adopting in a dart course of a race track by keeping a particle diameter over a long period of time, and adopting elastic chips machined to such a shape not to damage the eyes of a horse. SOLUTION: In the structure of a ground surface where elastic chips which are 7 to 0.05 mm in size, preferably about 5 to 0.5 mm, made of elastic material, and have the specific gravity of about 1.8 to 3.5 are laid as a cushion layer singly or in mixture with river sand to have a substantially designated thickness, preferably be 50 to 100 mm thickness on a roadbed layer, the elastic chips are deformed to be block-like in the central part, and flattened or minced meat- like in its periphery, and preferably the peripheral part occupies 1/20 to 8/20 of the area to the central part.
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