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中文核心期刊

砂岩不同含水特性对超低摩擦效应影响试验研究

EXPERIMENTAL STUDY ON THE INFLUENCE OF DIFFERENT WATER CONTENT CHARACTERISTICS OF SANDSTONE ON ULTRA-LOW FRICTION EFFECT

  • 摘要: 为揭示应力扰动下巷道砂岩含水特性对超低摩擦型冲击地压影响机制, 利用自制超低摩擦试验装置, 以沈阳某矿砂岩为研究对象, 通过改变砂岩块体含水率和浸水高度分别模拟深部岩体整体和分层含水特性, 以中间砂岩为工作块体, 利用其峰值水平位移和岩岩界面合摩擦力分别表征超低摩擦效应强度和阻力, 开展砂岩不同含水特性对超低摩擦效应影响试验研究. 研究结果表明: (1) 不同含水率和浸水高度工作块体位移时程曲线, 均有准备、冲击和振荡三个阶段性特征, 同时其峰值水平位移随垂直扰动频率增加均具有明显分区特性, 超低摩擦效应强影响区和弱影响区分界处峰值水平位移均值分别为0.232 mm和0.368 mm. (2) 工作块体干燥、饱和含水率下超低摩擦效应平均强度分别比自然含水率状态下高165%和89.7%, 含水率增加后摩擦力平均最大降幅为16.6%, 表明砂岩含水率由自然状态下继续增加易发生超低摩擦效应但强度减弱. (3) 工作块体浸水高度75 mm时超低摩擦效应强度平均增幅146%, 摩擦力最大降幅为12.1%, 表明此时易发生超低摩擦效应且强度较高. (4) 砂岩块体含水率1.05 %和浸水高度75 mm时, 超低摩擦效应强度最高, 实际工况中需合理控制岩体含水率和浸水高度, 防止超低摩擦型冲击地压灾害发生.

     

    Abstract: To reveal the influence mechanism of water-bearing characteristics of tunnel sandstone on ultra-low friction type impact ground pressure under stress disturbance, a self-made ultra-low friction test device was used. Taking the sandstone in Shenyang as the research object, The whole and layered water-bearing characteristics of deep rock mass are simulated by changing the water content and immersion height of sandstone block. Taking the intermediate sandstone as the working block, the peak horizontal displacement and the friction force of rock-rock interface were used to characterize the strength and resistance of ultra-low friction effect respectively, and experimental study on the influence of different water content characteristics of sandstone on ultra-low friction effect was carried out. The results show that: (1) The displacement time history curves of working blocks with different water content and immersion height have three stages of preparation, impact and oscillation. At the same time, the peak horizontal displacement has obvious zoning characteristics with the increase of vertical disturbance frequency. The average value of peak horizontal displacement at the boundary of strong influence zone and weak influence zone of ultra-low friction effect is 0.232 mm and 0.368 mm respectively. (2) The average strength of ultra-low friction effect under dry and saturated water content of working block is 165 % and 89.7 % higher than that under natural water content, respectively. The average maximum reduction in friction due to increased moisture content is 16.6%, indicating that the water content of rock mass continues to increase from natural state, which is prone to ultra-low friction effect but the strength is weakened. (3) The average increase in the strength of the ultra-low friction effect of the working block immersion height of 75 mm is 146 %, and the maximum decrease in friction is 12.1 %, indicating that the ultra-low friction effect is prone to occur currently and the strength is high. (4) When the water content of sandstone block is 1.05 % and the immersion height is 75 mm, the strength of ultra-low friction effect is the highest. In the actual working conditions, the water content and immersion height of rock mass should be reasonably controlled to prevent the occurrence of ultra-low friction rock burst disaster.

     

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