U-ironBNC²³⁶²¹³⁺¹ 基本例句 n.槽铁¹⁰⁰ According to fracturing mechanism of shaft wall in mining district such asHuaibei, Datun, Xuzhou, etc. , analysed the shortcomings of reinforced methods of U-iron shaft ring and grouting; 根据淮北、大屯、徐州等矿区井壁破裂机理，分析了槽钢井圈加固法和注浆加固法的缺点； cnki