Buried workings for constructing facilities e.g. car parks - are hollowed out under vault slabs and reinforced shaft formed from which lateral cutting is made under side umbrella vault

摘要

A subterranean vault (6) is made whose paving slabs have a constant width and beneath which the hollow working is made. Along one side of the vault holes are drilled with horizontal axes, perpendicular to the subterranean passage axis, intended to form a side umbrella vault. A reinforced shaft (13) is formed of height corresponding to that of the depth of the working under the vault slab. From this shaft a lateral cutting is made and concreted beneath the side umbrella vault. A wall (17) and the upper slab of the side vault is made so that the width of the working is greater than that of the subterranean passage and may be variable along its length. ADVANTAGE - Allows the working width to vary with minimum risk of subsidence.