大断面复合顶板硐室围岩稳定性规律及支护对策
Support Measures and Stability Law of Large Cross Section Chamber with Compound Roof
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摘要: 基于潞安集团李村煤矿2302工作面回风平巷地质条件,采用理论分析和数值模拟的方法,研究大断面复合顶板巷道掘进过程中的围岩应力和变形规律,分析巷道帮部开挖钻场后形成的大断面复合顶板空间围岩的稳定性演化特征,揭示了二次扰动后大断面复合顶板硐室围岩稳定性劣化规律,提出了“高强锚杆+双层钢筋梯子梁+锚索+钢筋网”的联合支护方案。研究表明:2302工作面回风平巷掘进形成后,两帮围岩变形量为270 mm,顶板变形量达到150 mm以上;顶板应力扰动范围达到13 m以上;钻场开挖造成巷道围岩二次扰动,与2302工作面回风平巷稳定性相互加速劣化,其顶板下沉量增加至200 mm,顶板应力扰动范围增加至16 m以上。经现场围岩变形量观测可知,巷道及钻场采用联合支护方案后,其围岩变形量均在120 mm以下。Abstract: Based on geological conditions of return air roadway of 2302 working face of Lu’an Group, using the methods of theoretical analysis and numerical simulation, we researched the surrounding rock stress and deformation law of compound roof during the process of roadway tunneling, analyzed the stability evolution characteristics of space surrounding rock of large-section composite roof formed after the excavation and drilling site at the roadway side, revealed the stability degradation law of the surrounding rock in the large-section composite roof chamber after the secondary disturbance, proposed “high strength anchor bolt +double reinforced ladder beam + anchor cable + steel fabric mesh” combination supporting scheme. The results show that the deformation of the two sides is 270 mm and roof is more than 150 mm after the formation of the return air drift in 2302 working face. The disturbance range of roof stress is more than 13 m. The excavation in the drilling field caused secondary rock disturbance in the roadway, and the deterioration of the return air drift stability in 2302 working face is accelerated. The roof subsidence increased to 200 mm, and the roof stress disturbance range increased to more than 16 m. According to the observation of the deformation amount of surrounding rock in the field, the deformation amount of surrounding rock is below 120 mm after the combined support scheme is adopted in the roadway and drilling field.