Method and apparatus for placement of a subterranean curtain below the face of the earth

1. A method to reinforce a dike by placement of a subterranean water-permeable curtain below the face of the earth, comprising the steps of:

selecting an area with soil in which the subterranean curtain is to be placed;

carving a slit at a predefined location in the soil;

providing a movable casing in said slit;

providing the movable casing with the curtain;

dispatching the curtain from the movable casing into the slit; and

closing said slit, and

wherein carving the slit and providing the subterranean curtain in said slit is executed in an area with a predefined stratification of a sand layer and a clay layer on top of said sand layer, wherein:

after dispatching the water-permeable curtain from the movable casing into the slit, sand and clay is introducing in the slit on opposite sides of the water-permeable curtain so as to close said slit and restore the area's original stratification of sand and clay.

2. The method according to claim 1 , additionally comprising selecting the subterranean water-permeable curtain as an impermeable curtain for preselected material not being water, and providing the curtain below the face of the earth to restrict movement of said preselected material from one side of the curtain to an opposite side of the curtain.

3. The method according to claim 1 , additionally comprising providing the water-permeable curtain with guide wires and providing the movable casing with one or more guides that cooperate with said guide wires so as to position the curtain vertically within the slit.

4. The method according to claim 1 , additionally comprising dispatching measurement wires from the movable casing on opposite sides of the curtain simultaneously with the dispatching of the curtain from the movable casing.

5. The method according to claim 4 , additionally comprising embodying the measurement wires as hybrid wires, comprising glass fibers with an electrically conducting core wire.

6. The method according to claim 1 , additionally comprising providing the clay in the form of swell clay.