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不同含水率红砂岩单轴压缩试验声发射特征研究

Technology of Advanced Pre-grouting Reinforcement in Tailentry of Fully-mechanized Caving Coal . Face

  • 摘要: 利用微机控制电液伺服岩石三轴试验机,分别对不同含水率砂岩进行常规单轴压缩试验,加载过程中同时进行声发射(AE)检测,得到4种不同含水率试样全应力-应变曲线、声发射振铃数和累计振铃数曲线。结果表明:水对砂岩的力学特性和声发射特征有较大影响;峰值前不同含水率试样应力-应变曲线无明显屈服特征,而应力与声发射累计振铃数曲线有明显的台阶出现;岩样声发射振铃数在加载过程中基本呈递增趋势,越接近后期增加越明显,峰值处声发射振铃数达到最大,声发射累计振铃数以近乎直线方式增长;峰值后应力与声发射振铃数同时减小。含水率越高,砂岩声发射振铃数越少且越滞后,但各种试样所得声发射累计振铃数曲线在形状上相似。

     

    Abstract: Due to the tailgate surrounding rock near terminal line was difficult to be controlled caused by strong mining influence, this paper focused on the charact eristics that the No.2305 coal face tailgate near terminal line repeatedly affected by pressure in Zhangcun Coal Mine, large displacement affected the safe withdrawl of hydraulic supports. The factors of damage were given, this paper analysed the influence sphere of the driving dynamic pressure, the impact of the advanced abutment st ress at adjacent coal face, the lateral abutment stress in the goaf and the abutment stress in coal face based on numerical simulation, and proposed grouting reinforce ment measures.The results showed that technology of advanced pre-grouting reinforcement made two sidewalls convergence reduced by 1 206 mm and roof-to-floor co nvergence reduced by 535 m.

     

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