| 摘要 |
<p>PURPOSE:To drill a vertical well with a large diameter simply by a method wherein, in drilling a deep aeration tank for treating water, a vertical well with a small diameter and a desired depth is firstly drilled by an impact drilling body and thereafter, the drilling is carried out by replacing a leading end cylindrical body of the same drilling body with one having a larger diameter. CONSTITUTION:An impact drilling body 14A equipped with the first cylindrical portion 14b mounted to a leading end of a cylinder 14a having a diameter larger than that of said cylinder 14a is repeatedly dropped to drill a vertical well with a diameter smaller than that of a disired diameter. Subsequently, the impact drilling body 14A is drown upwardly from the vertical well and a drilled substance removing body 15 is entered into the vertical well and, by carrying out the dropping motion thereof, drilled soil, sands or stones accumulated in a well bottom are exhausted out of the vertical well. This operation is repeatedly carried out to drill a vertical well with a small diameter and an objective depth of 1,000m or more. Subsequently, the second cylindrical portion 14c with a diameter larger than that of the first cylindrical portion 14b is welded to the leading end of the impact drilling body 14A and is used as an impact drilling body 14B for enlarging a diameter to enlarge the diameter to form a well G with a further larger diameter. Said operation is repeated until a well with an objective inner diameter in attained, and accordingly, a vertical well for a deep aeration tank in the ground within a short time by a simple installation is obtained.</p> |
