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针对深部高应力条件下复合型顶板煤巷的大变形问题,以江西曲江煤矿为例进行了现场调查、理论分析和工业试验等研究。首先,经现场调查发现该矿表现出了典型“三高”矿井的特点,加上顶板锚索和两帮锚杆无法充分发挥作用,使整个巷道支护系统失去平衡而发生破坏。然后,研究了深部高应力工作面煤巷的力学作用,认为该力学作用是一个渐进过程,其变形动力主要来自于巷道顶板压力,底板变形大是直接导致整个巷道系统失效的重要标志;另外,根据深部高应力复合型顶板煤巷的受力特征,建议应将顶板的控制作为关键部位,尽力维护顶板的完整性,提高岩层自承能力,使支护结构与围岩能够协调地工作,并提出了以“预应力桁架锚索”为主体,以“锚杆+锚索+钢筋网等支护”为辅助的综合控制技术。实践证明:经以“预应力桁架锚索”为主体的综合控制技术支护后的巷道,其变形较原支护有明显好转;监测数据表明:经91 d后,巷道两帮的相对收敛速率小于1.7 mm/d,而且顶底板的相对收敛量大大减少,最大值为297 mm,变形速度小于1.4 mm/d,处于稳定状态。
Aiming at the large deformation of the compound roof coal roadway under the condition of deep high stress, this paper takes Qujiang Coal Mine in Jiangxi Province as an example to conduct field investigation, theoretical analysis and industrial experiment. First of all, the site survey found that the mine has shown the characteristics of a typical “three high” mine, coupled with the roof anchor and two groups of bolts can not fully play the role of the entire roadway support system out of balance and destruction. Then, the mechanical action of the coal roadway in deep high stress working face is studied, and the mechanical action is considered as a gradual process. The deformation dynamic mainly comes from the pressure of the roof of the roadway and the deformation of the bottom plate is an important symbol which directly leads to the failure of the entire roadway system. In addition, According to the stress characteristics of deep seam with high stress and high compound roof, it is suggested that the control of the roof should be taken as the key part to try to maintain the integrity of the roof, to improve the bearing capacity of the rock, so that the supporting structure can work in coordination with the surrounding rock. The comprehensive control technology supported by “prestressed truss anchor cable ” as the main body and “anchor bolt + anchor cable + steel mesh supporter” is proposed. Practice has proved that: the deformation of the roadway supported by the integrated control technology whose main body is “prestressed truss anchor cable” is obviously improved compared with the original support; the monitoring data shows that after 91 d, Convergence rate is less than 1.7 mm / d, and the relative convergence of the top and bottom plates is greatly reduced, the maximum value is 297 mm, the deformation speed is less than 1.4 mm / d, and is in a steady state.