Water-impermeable linings

(Figure # 1) The water-impermeable liningsWATER-IMPERMEABLE LININGS (EN: water-proof supports; DE: wasserdichter Ausbau, wasserdichte Ausbauarten; FR: cuvelages; ES: encubados, revestimientos estancos al agua; RU: водонепроницаемые крепи) are the special types of the permanent mining lining, which are purposed for the prevention of the infiltration of the underground waters into the mine workings, and for the prevention of the destruction of the material of the lining by the water.

The water-impermeable linings are used during the conducting of the mine workings within the water-flooded rocks, when, according to the conditions of the operation, there is not acceptable the infiltration of the underground waters through the lining (the shafts of the underground salt mines, the tunnels of the metropolitan subways, and so on). Within the structure of the water-impermeable lining, there are included one or more elements, which perform the role of the water-barrier shields. There have obtained the largest distribution the hollow structural section linings, and the steel-concrete linings. The water-impermeable lining of the hollow structural sections (see the Figure # 1) is assembled of the individual cast iron or steel elements, namely, of the hollow structural sections, which are connected among themselves using the bolts. For the lining of the underground mine shafts, there are produced within the USSR the hollow structural sections of the cast iron, and they produce the special hollow structural sections for the metropolitan subways. The space between the hollow structural sections and country rocks is filled with the plugging fluid or concrete (see the Figure # 1, a). For the improvement of the water impermeability of the lining, they sometimes introduce into its structure the additional waterproofing elements: the layer of the polymeric materials, for example, of the plastic-concrete (see the Figure # 1, b), or the water-barrier shield of the rolled materials, for example, of the polyethylene, or polyisobutylene (see the Figure # 1, v). For the maintainance of the water impermeability of the lining, which is made of the hollow structural sections, during the operation, they periodically conduct the works for the water suppression. The water-impermeable lining, which is made of the hollow stru ctural sections of the cast iron, is widely used abroad, especially during the penetration of the mine workings using the method of the freezing.

The steel-concrete water-impermeable lining (see the Figure # 2) comprises the external and internal shells (ferrules), which have been produced of the sheet steel or profile steel.

(Figure # 2) The steel-concrete liningThe space between these shells is filled with the concrete. For the strengthening of the bond with the concrete, they equip the external side of the internal shell with the special brackets (anchors). Using the high-quality welding of the elements of the shells, there is ensured the complete water impermeability of the steel-concrete lining, which fact excludes the necessity for the conducting of the works for the water suppression during the operation. The thickness of the internal steel shell is 10-85 millimetres, and the thickness of the concrete layer is 300-600 millimetres. The steel-concrete water-impermeable lining has obtained the largest distribution within the Western Europe, and partly within Canada, during the penetration of the underground mine shafts using the special methods (drilling, freezing); this lining was used for the underground mine shafts to the depth of 1000 metres. For the purpose of the improvement of the water impermeability, they place between the temporary lining and permanent water-impermeable lining the additional waterproofing layer of the bitumen (asphalt) with the thickness of 100-150 millimetres (see the Figure # 2, b).

For the improvement of the effect of the waterproofing, and for the improvement of the conditions for the operation of the water-impermeable lining, they perform the plugging of the rocks.