Research On Flexible Formwork Concrete Gob-side Entry Retaining In Half Coal Crag Tunnel

As a new support technology, flexible formwork concrete gob-side entry retaining isconstantly promoted in the field of mining engineering. The technology keeps up with themining face and pours a closed continuous concrete wall between the gob and the roadway,making up the deletion on the side of roadway. The wall forms a whole with the originalroadway supporting to share mining dynamic pressure and maintain roadway stability. Theentry retaining can be the gateway of next working face. Furthermore, it can also satisfy somespecial requirements of face mining isolated gas, prevention of water, fire and so on.The paper is based on the flexible formwork concrete gob-side entry retainingengineering in the21210fully mechanized coal mining face of Xiayukou Coal Mine, and thetail entry of working face21210is a half-coal rock lane. By researching rock control theory ofgob-side entry retaining in half coal crag tunnel, the paper conducts tunnel support design,roadside support design, temporary support design and construction organization design.Furthermore, the paper discusses the concrete structure performance and mechanics of theseparation wall. Mechanical parameter flexible formwork concrete is obtained via physicallaboratory tests. On the basis of research, Geotechnical numerical simulation softwareMidas/GTS is used to set up simulation analysis model of flexible formwork concretegob-side entry retaining, getting surrounding rock stress and deformation law and verifyingthe design. In the process industrial tests, construction technology of half flexible formworkconcrete gob-side entry retaining is researched to ensure the retaining closed. The problem ofgas in mine-out area can be solved by drawing out them through pre-buried pipelines in theflexible formwork concrete walls and ensuring the tightness of the support. The law of minepressure and deformation is summarized to adjust and optimize them to improve the entire process, so as to achieving the purpose of the study.Conclusion in half the coal and rock along the supporting engineering for soft moldconcrete studied in the paper are as follows:(1) Sandstone platform of half coal and rockretaining are strengthened to prevent the shear destroying to support flexible formwork andconcrete wall effectively.(2) Numerical simulation and by field monitoring verifies thatsurrounding rock deformation of flexible model support is roughly similar with the conditionsunder coal pillar flexible model concrete walls can replace coal pillar and the best width offlexible model concrete walls is1meter.(3) Flexible formwork concrete is used in fullymechanized working face of double thin coal seam outburst mine implementation. Gas inmined-out area can be effectively managed by using flexible template for gob drainage andguaranteeing impermeability of support.(4) Flexible formwork concrete has the property ofrapid hardening and earlier strength. It is fully connected with the top and can timely supportroof. Canceling the coal pillar can reasonable mine coal resources, improve the recovery rateand raise economic benefit.