| 摘要 |
Excavated spaces in mining and tunnelling which are additionally stressed by the working are secured with a roadway support system which consists of rigid steel arches and sealing lagging as well as of a backfilling designed so as to yield as a unit. In this arrangement, a plastic or virtually plastic, non-setting material, such as clay, loam or a mixture of lime sand and oil or bitumen, is used as the backfilling. By providing escape cavities in the seam or in the rock or by suitable openings in the lagging, the plastic material can escape if excess pressure occurs, so that always roughly the same resistance is applied by the roadway support system overall. The steel arches have the cross-section necessary or required after completion of the convergence, which cross-section does not vary during the life of the roadway due to the introduction of the yielding capacity into the backfilling. <IMAGE>
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