Method for introducing a moisture-impermeable layer into the ground, as well as a trench obtained by such a method

Abstract

A method for introducing a moisture-impermeable layer into the ground, wherein the moisture-impermeable layer is placed into the ground in a trench, which trench is supported by one or more casing members and filled with a clay-containing mixture of dry solids, which mixture can form a moisture-resistant gel, comprising powdery or pulverized smectite and/or smectite-containing natural rock and a water-soluble polymer.

1 . A method for introducing a moisture-impermeable layer into the ground, wherein the moisture-impermeable layer is placed into the ground in a trench, characterized in that the trench is supported by one or more casing members, which trench is subsequently filled with a clay-containing mixture of dry solids, which mixture can form a moisture-resistant gel, comprising powdery or pulverized smectite and/or smectite-containing natural rock and a water-soluble polymer.  
     
     
         2 . A method according to  claim 1 , characterized in that the trench in the ground is obtained by using one or more casing members, wherein one or more hollow elements are installed in the ground, said elements consisting of at least two plates which are interconnected by means of spacers, which plates may include a disconnectable closure part on their bottom sides.  
     
     
         3 . A method according to claims  1 - 2 , characterized in that said the hollow element is filled with the clay-containing mixture of dry solids first before it is installed in the ground in order to obtain a trench containing a clay-containing mixture of dry solids.  
     
     
         4 . A method according to claims  1 - 2 , characterized in that the hollow element is installed in the ground first, after which it is filled with the clay-containing mixture of dry solids in order to obtain a trench containing a clay-containing mixture of dry solids.  
     
     
         5 . A method according to claims  1 - 4 , characterized in that the element filled with the clay-containing mixture of dry solids is removed from the trench in such a manner that the clay-containing mixture of dry solids that remains behind in the trench is densified.  
     
     
         6 . A method according to  claim 5 , characterized in that said element is removed from the trench by being vibrated, wherein the closure part that may be present is disconnected and remains behind in the ground.  
     
     
         7 . A method according to claims  1 - 6 , characterized in that first the hollow element is lined with a material on the inside, after which filling with the clay-containing mixture of dry solids takes place, which material prevents the clay-containing mixture of dry solids from adhering to the hollow element.  
     
     
         8 . A method according to  claim 1 , characterized in that the trench that has been formed in the ground is lined on both longitudinal sides thereof with one or more casing members consisting of one or more panels, after which the space thus enclosed by the panels is filled with the clay-containing mixture of dry solids.  
     
     
         9 . A method according to  claim 8 , characterized in that the panels are lined with a material on the side facing away from the soil before the panels are filled with the clay-containing mixture of dry solids, which material prevents the clay-containing mixture of dry solids from adhering to the panel.  
     
     
         10 . A method according to claims  8 - 9 , characterized in that after the space enclosed by said panels has been filled with the clay-containing mixture of dry solids, said panels are removed from the trench in such a manner that the clay-containing mixture of dry solids that remains behind in the trench is densified.  
     
     
         11 . A method according to  claim 10 , characterized in that said panels are removed from the trench by being vibrated.  
     
     
         12 . A method according to claims  1 - 11 , characterized in that the clay-containing mixture of dry solids that is present in the trench is densified by vibrating one or more hollow elements or panels.  
     
     
         13 . A method according to claims  5 - 6  and  10 - 12 , characterized in that a supplementary amount of clay-containing mixture of dry solids is added to the densified clay-containing mixture of dry solids in the trench.  
     
     
         14 . A method according to  claim 1 , characterized in that a mat consisting of two geofabric cloths, between which the clay-containing mixture of dry solids is fixed, is installed in the trench as the casing member.  
     
     
         15 . A method according to claims  1 - 14 , characterized in that a supporting fluid is used when forming the trench in the ground, in order to prevent the side walls of the trench from caving in.  
     
     
         16 . A method according to  claim 15 , characterized in that said supporting fluid be forced out of the trench upon installation of one or more hollow elements and/or mats in the trench.  
     
     
         17 . A method according to claims  1 - 16 , characterized in that the smectite is in an inactive state, that is, the lattice sodium and lithium ions that may be present do not make up more than 30% of the sum of the exchangeable lattice cations.  
     
     
         18 . A method according to claims  1 - 17 , characterized in that the clay-containing mixture of dry solids additionally comprises a powdery solid activating agent in an amount of 0.8-6.0 wt. %, based on the weight of the smectite.  
     
     
         19 . A method according to claims  1 - 18 , characterized in that the clay-containing mixture of dry solids additionally comprises more than 0.5 wt. % of one or more solid inert fillers having an average particle size of more than 0.05 mm, based on the weight of the smectite.  
     
     
         20 . A method according to claims  1 - 19 , characterized in that said solid inert filler is sand, a silica compound, pulverized rock or a mineral, a pulverized ceramic material or a mixture thereof.  
     
     
         21 . A method according to claims  1 - 20 , characterized in that the clay-containing mixture of dry solids contains 1-95 wt. % of a solid inert filler, based on the weight of the overall mixture.  
     
     
         22 . A method according to claims  1 - 21 , characterized in that said solid inert filler has a particle size of 0.1-8.0 mm.  
     
     
         23 . A method according to claims  1 - 22 , characterized in that said clay-containing mixture of dry solids has a moisture content of less than 20%.  
     
     
         24 . A trench obtained in accordance with the method as defined in claims  1 - 23 .