Method for providing a substantially leakproof shielding layer in the ground and a device for performing the method

A method of providing a substantially leakproof shielding layer (8,9) in ground comprising porous rock and soil, the method comprising:

• a) making a plurality of holes (H) in a surface of the ground by means of a guided drill head (4) which ejects ground-decomposing liquid mainly in an advancing direction of the head, and
• b) passing through each hole an injection head (6) which ejects injection liquid essentially transversely to the advancing direction thereof, so that the injection liquid will penetrate into the ground material and will mix therewith and after transition to a solid state, together with injection liquid in an adjacent hole, which has also penetrated into and mixed with the ground material and has transformed into a solid state, will form part of the shielding layer, wherein making a hole is initiated at a first location (S1) and completed at a second location (S2) on the ground surface spaced therefrom, wherein, on completion of making a hole and connecting a cable to one of the drill head (4) and a drill string (3) connected thereto, when one of the drill head and the end of the drill string connected to the drill head is accessible at the second location (S2), said end of the drill string is retracted to the first location, whereupon the injection head (6) is connected to said cable at the second location and is drawn through the hole (H) towards the first location (S1) and then back towards the second location, when injection liquid is ejected in at least one of said drawing directions.

A method of providing a substantially leakproof shielding layer (8,9) in ground comprising porous rock and soil, the method comprising:

• a) making a plurality of holes (H) in a surface of the ground by means of a guided drill head (4) which ejects ground-decomposing liquid mainly in an advancing direction of the head, and
• b) passing through each hole an injection he ad (6) which ejects injection liquid essentially transversely to the advancing direction thereof, so that the injection liquid will penetrate into the ground material and will mix therewith and after transition to a solid state, together with injection liquid in an adjacent hole, which has also penetrated into and mixed with the ground material and has transformed into a solid state, will form part of the shielding layer, wherein the making of the hole is initiated at a first location (S1) and is completed at a second location (S2) spaced from the first location on the ground surface, wherein, on completion of making a hole and connection of a cable to one of the drill head (4) and a drill string (3) connected to the drill head, when the one of the drill head and an end of the drill string connected to the drill head is accessible at the second location (S2), said end of the drill string is retracted to the first location where said drill head and drill string are disconnected from said cable and the injection head is connected to said cable and is drawn thereby through the hole to the second location and then back towards the first location, while ejecting injection liquid.