Skew Roof Deformation Mechanism in Longwall Gateroads -Concepts and Consequences

摘要

A research project was commissioned by the Australian Coal AssociationrnResearch Program (ACARP) to improve the understanding of tailgaternstrata mechanics and to provide a more rigorous engineering basis forrntailgate support design. A deformation mechanism termed ‘skew roof’rnwas defined which relates the regional influence of differential horizontalrnstrata movement (shear) about longwall extraction to gateroads.rnConfirmation of the mechanism was achieved by field investigationsrnwhich included measurement of the shear displacement along weakrninterfaces. Under geological and mining conditions where the skew roofrnmechanism operated, strata units were found to move progressivelyrnfurther towards the goaf with height into the roof. 3D numericalrnmodelling was used to assess the major geotechnical factors controllingrnthe mechanism and to determine appropriate support strategies within arn‘skew roof’ environment including the role of cables versus standingrnsupports. The skew mechanism is considered relevant to; all roadways inrnthe vicinity of longwall extraction including the faceline itself, chainrnpillar design, and support design.