Research on Mechanical Properties of U-Shaped Retractable Gangue Prevention Structure of Gob-Side Entry by Roof Cutting and Pressure Releasing in Deep Mining

Abstract In recent years, as a new type of gob-side entry retaining method, roadway automatically formed by roof cutting and pressure releasing (RAFRCPR) has been widely used in China. Under the condition deep mining, deformation gangue rib is difficult to control, it for traditional I-shaped steel provide needed support. To effectively control rib, U-shaped retractable prevention structure (URGPS) with high lateral support strength axial compressible dynamic absorption energy proposed. Based on geological conditions 21304-working face Chengjiao coal mine Henan, mechanical characteristics URGPS causes its local instability are analyzed detail employing theoretical analysis, laboratory tests, numerical simulation. A reasonable bolt tightening force, overlap length, lap combination form determined according actual situation project site. Engineering practice shows that was applied roof-cutting effective.