| 摘要 |
<p>A method of accessing water from an aquifer which underlies an impervious stratum without contamination of the aquifer by polluted water from above the stratum by drilling a bore hole to the aquifer; comprises the steps of (a) drilling a first bore hole into, but not through the impervious stratum and a second bore hole of smaller diameter to the aquifer; (b) inserting therein a protective tube of diameter intermediate between those of the bore holes and which extends to the ground surface; and (c) adding a protective mortar to the annular space between the protective tube and the larger diameter bore hole; there being circumferentially wound around the tube at the level of the protective mortar, transfer tubing which comprises radial perforations which permit passage of fluids, e.g. sealing composition from the interior of the transfer tubing to the mortar. The method works best with certain reinforced mortar formulations.</p> |
