Numerical simulation analysis and field monitoring of support with steel corrugated webs in Baijigou Coal Mine

Since excessive deformation of the No.11 mining I-beam supports and insufficiency of support strength in the thick coal seam mining roadway of the southern wing of Baijigou Coal Mine, support with steel corrugated web of high strength steel is proposed for support to improve the stability of the roadway, which is composed of steel corrugated web beams and welded I-steel legs. Based on the numerical simulations of roadway excavation, deformation and stress developments of surrounding rock are analyzed under three support conditions, such as unsupported, supported by mining I-beam, and supported by steel corrugated web. In the transportation entry roadway of Baijigou Coal Mine, a test section is selected to replace the double-shed mining I-beam supports with a single shed of steel corrugated web support. Field deformation and support reaction monitoring are conducted on the steel corrugated web support. The results show that without any support, the vertical deformation of the roadway roof reaches 243 mm and the convergence of the two sides of the roadway reaches 114 mm. After installing No.11 mining I-beam supports and supports with steel corrugated web, the vertical deformation decreases to about 60.0 mm and 25.5 mm and the convergence of two sides also decrease to 56 mm and 28 mm, respectively. The support effect of the supports with corrugated webs is significantly better than that of No.11 mining I-beam support. Field monitoring results show that the mid-span convergence of corrugated web beam decrease by 54% compare to I-beams, and the convergence of welded I-steel legs decrease by 80% on average compare to mining I-shaped legs. Support reaction forces detected on corrugated web supports fluctuate within a small range, with a maximum reaction of 2.6 MPa.