Classification and support selection of surrounding rock stability of roadway
Clustering center value of classification index of surrounding rock stability of roadway mining roadway Roadway category σ top / Mpa σ coal / Mpa σ bottom / Mpa N H/m X D/m I (very stable) 95 25 60 0.03 260 0 24.3 II (stable) 50 18 35 2.35 300 0.105 14.9 III (medium stability) 30 12 12 3.10 380 0.365 10.3 IV (unstable) 45 16 30 2.65 340 0.576 11.9 V (very unstable) 25 11 11 3.19 410 0.765 9.7 The coal pillar width index of the roadway is linearized and clustered The average value and range value of the surrounding rock movement of various roadways Roadway surrounding rock stability category The amount of the top and bottom plates of the mining roadway is close/mm Develop and prepare the roadway floor and floor closer/mm average value Range value average value Range value I 30 10~50 25 0 to 50 II 75 50~100 75 50~100 III 250 100~400 150 100~200 IV 500 400～600 400 200~600 V 1200 600～1800 1000 600~1400 Note: For the lanes belonging to Class I and Class V, when calculating the approaching amount, u 1 and u 5 respectively take the minimum and maximum values ​​within the range of the near amount. Basic support form and main parameters of roof bolts in coal roadway Roadway category Roadway surrounding rock Stable condition Basic support form Main support parameters I Very stable Integral sandstone , limestone rock formations, unsupported Other rock layers, single anchor End anchor rod diameter ≥16mm, rod length 1.6～1.8m, spacing between 0.8～1.2m, design anchoring force≥64～80kN II stable The top plate is relatively complete, the single anchor The top plate is broken, the bolt + net End anchor rod diameter ≥16～18mm, rod length 1.6～2.0m, spacing between 0.8～1.0m, design anchoring force 64～80kN III Moderately stable The top plate is relatively complete, the anchor + reinforced beam or truss The top plate is broken, the anchor + W steel strip (or steel beam) + net, Truss + net, or add anchor End anchor rod diameter ≥16～18mm, rod length 1.6～2.2m, spacing between 0.6～1.0m, design anchoring force 64～80kN Full-length anchoring rod diameter ≥18～22mm, rod length 1.8～2.4m, spacing between 0.6～1.0m, IV Unstable Anchor + W steel belt + net, or increase anchor cable Truss + net, or add anchor Full-length anchoring rod diameter ≥18～22mm, rod length 1.8～2.4m, spacing between 0.6～1.0m, V Extremely unstable More complete roof, yieldable anchor + metal stent, or increasing the anchor; more top plate broken bolt + net + yieldable metal stent, or increasing the anchor; severe floor heave, + anchor stent ring may be reduced Full-length anchoring rod diameter ≥18～24mm, rod length 2.0～2.6m, spacing between 0.6～1.0m, High elastic design, one-piece fit without restraint, excellent fabric absorbs sweat and breathes. The special design provides pressure to the body, and flexion and extension exercises can also fit comfortably. China Eva Ski Back Protector,Back Protector For Sking manufacturers, welcome Back Protector For Snowboarding,Adult Back Protector purchasers from worldwide to visit our site. Eva Ski Back Protector,Back Protector For Sking,Back Protector For Snowboarding,Adult Back Protector Dongguan Yoloon Sports Goods Co.,LtD , https://www.dgyoloonprotection.com