瀬戸内海における削孔試験
海底岩盤の削孔 (第2報)
1973 年 89 巻 1021 号 p. 155-160
詳細
1973 年 89 巻 1021 号 p. 155-160
The authors built a special thermodrill which could operate under water. The piercing test on a granite mass at the bottom of the sea was carried out in the Seto Inland Sea. The quantity of oxygen gas fed to the burner was 1.5 Nm3/min and kerosene 0.7l/min. The total pressure of the jet stream was 16kg/cm2, with a velocity of 2, 000m/sec and temperature of 3, 500°K.
The authors also carried out piercing tests on many granite blocks, each with a volume of about one cubic meter. These blocks were sunk to the bottom of the sea at the depth of 5 meters. The mean piercing rate was 40cm/min, with the maximum of 80cm/min. The average diameter of the holes was between 100 and 110mm. This thermodrill is quite useful for piercing anchor holes on the sea bed, for removing hard projecting rocks in the Seto Inland Sea and for excavation rocks at the bottom of the sea.
