矿用预应力钢棒支护成套技术开发及应用

 为了解决目前煤矿锚杆支护材料存在的问题，采用实验室试验、数值模拟及现场试验相结合的手段及方法，开发矿用预应力钢棒支护成套技术，包括钢棒材料、锚具、构件、锚固方式、施工工具及技术等；实验室试验得出钢棒屈服强度不低于1 140 MPa，抗拉强度不低于1 270 MPa，延伸率大于15%，冲击吸收功不低于30 J，开发与钢棒强度匹配的托板及锚具；数值分析钢棒应力场分布特征及影响因素，得出在高预应力下，钢棒预应力场的应力值大，压应力区范围广，钢棒的主动支护作用明显。在潞安漳村煤矿25排水巷进行矿用预应力钢棒支护技术现场试验，巷道变形量不大，顶板离层基本为0，钢棒初始预紧力为100～120 kN，受力稳定，基本不受巷道掘进影响，支护效果良好。采用钢棒支护比高强锚杆支护材料费用下降29.5%，钢棒间排距大、预紧力施加快，可适当提高巷道掘进速度，具有较好的推广价值。

DEVELOPMENT AND APPLICATION OF MINE PRESTRESSEDSTEEL BARS SUPPORTING TECHNOLOGY

To deal with the problems associated with rock bolt materials in the coal mines，the complete support technology using prestressed steel bars，including steel bar material，locking device，component，anchoring method，machinery and procedure，was developed，based on numerical models，laboratory and field tests；according to laboratory tests，the yield strength of steel bars is not less than 1 140 MPa，the tensile strength is not less than 1 270 MPa，the extension ratio is more than 15%，the impacting absorbing energy is not less than 30 J，and the plates and locking devices compatible with the steel bar strength are developed. Numerical models are used to analyze the distribution characteristics of the stress field caused by steel bars，as well as the main affecting factors，under high prestressed conditions，the magnitude of the stress field caused by steel bars are big，the scope of compressive stress is widely spread，and the active support performance of steel bars is obvious. Field support trials using prestressed steel bars were carried out in the water-discharging roadway of Zhangcun coal mine，Luan coalfield，the displacements of roadways are moderate，no roof separation is shown，the pre-tensioned force is 100–120 kN，the force of steel bars is stable and not affected by the roadway development，and the support performance is good. The cost of using steel bars is less than that of using high strength rock bolts by 29.5%，the spacing of steel bars is big，the installation of pre-tensioned force is fast，the speed of roadway development can be improved to some extent，and this support technology is deserved to be promoted.