Determination of the parameters of local reinforced zones under the protection means

Abstract

In order to develop effective measures to ensure the operational condition of the development workings behind the face in the conditions of soft footwall rocks, the construction of local reinforced zones under the protection means has been proposed. The presence of such zones allows transferring the current load deep into the massif and creating a stable foundation under the protective structure. The results of researches concerning establishment of rational parameters of local reinforced zones with application of the method of finite elements, the method of experiment planning and the method of statistical processing of these results have been presented. The empirical dependence of the subsidence of the local reinforced footwall under the protection means on their load, deformation characteristics of the local reinforced zone and host rocks, width of protection means, strength of soft underlying rocks and geometric dimensions of the zone has been determined. The relative indicator of efficiency of local strengthening of a footwall which is used for determining of rational parameters of a locally reinforced zone has been offered.

Deformation as a process to transform shape and volume of protective structures of the development mine workings during coal-rock mass off-loading

“…Among other activity reducing the effect [7], certain measures are applied intended to redistribute stresses within a mine working foot through the reshaping of protective structures. Namely, DonNTU experts have proposed to use the following: piers which form differs from rectangular [8]; a protective structure deepening into a mine working foot [9]; and arrangement schemes of protective structures with compensatory cavities [10]. It should be mentioned that in the real coal-rock formation, rigid protective structures are in the boundary stress-strain state.…”