WATER TRICKLING AND ROOF FALLING OF SOFT ARGILLACEOUS ROADWAYS WITH ITS COMPOSITE SUPPORTING AND REPAIRING TECHNOLOGY
Wenyu Lv1, 2
1School of Energy Engineering, Xi’an University of Science and Technology, Xi’an, 710054, China
2Technology Centre, Sichuan Coal Industry Group Co., Ltd., Chengdu, 610091, China
Using methods such as the transient electromagnetic method, rock mechanics testing, X-ray diffraction analysis, rock strength weakening experiment, borehole observation technology and grout mix design, etc. to study the mechanism of water trickling and roof falling of soft argillaceous roadways, via model analysis and numerical calculations, we reached many conclusions: Rock breakage is perpendicular to the axis of borehole; expansion of argillaceous swelling rock weakens the surrounding rock, the strength degradation of which occurs in 1h; performance of anchor agent also significantly decreased; uniaxial compressive strength, friction angle and cohesion of surrounding rock decreased by 40%, 16.5% and 11.1%, respectively; water trickling further exacerbated the risk of roof falling in the construction of roadway; according to calculation, the weak plane of the original 12 # I-beam became shear failure, and cannot meet the large initial deformation of roadways, floor heave is large with serious water logging. We presented the technology of “targeted drainage, deep-and-shallow hole grouting, advanced ductile, floor anchor rope, U29-shaped steel, and anchor net spray composite support”. Site monitoring on 1# railway cross-cut of Bofang Coal Mime displayed that the maximum amount of deformation was less than 125mm, working resistance of anchor bolt and cable were 72-91kN and 123.3kN, respectively. Water trickling and roof falling were controlled; water logging of floor heave was improved obviously. Numerical simulations show that plastic zone is greatly reduced, and support effects were fairly good.