Shaft lining with cast-iron ring elements for deep freezing shafts in mining

摘要

In a shaft lining for the support of shafts sunk by the freezing method in unstable water-bearing rock, a water-permeable outer lining cylinder absorbs the rock pressure. Located between the outer lining cylinder and an inner lining cylinder is a sliding layer of asphalt, the specific gravity of which only slightly exceeds the specific gravity of water. The inner lining cylinder possesses a watertight steel casing as an inner delimitation relative to the asphalt layer and a ring column located inside the steel casing and consisting of a plurality of supporting rings stacked one above the other. Since only compressive, shearing and bending-pressure stresses have to be absorbed by the ring column of the inner lining cylinder, at great depths the support rings consist of cast-iron ring segments which have a H-shaped, that is to say approximately dumbbell-shaped profile. The horizontal webs have casting holes, through which filling concrete is poured into the interspace between two adjacent supporting rings. The cast-iron ring segments can consist of a cheap grade of cast iron. Such an inner lining cylinder is substantially more advantageous than a lining cylinder in which the supporting rings consist of composite reinforced-concrete rings, because, at greater depth, these composite rings must have very large thicknesses in order to be capable of withstanding the loads. IMAGE