不同椭圆率巷道冲击破坏特征试验研究

Experimental study on impact failure characteristics of roadway with different ellipticity

  • 摘要: 为研究椭圆率对巷道冲击破坏特征的影响机制,利用自主研发的深部煤岩冲击地压多功能物理模拟试验系统,开展了真三维条件下椭圆形巷道冲击破坏试验,分析了不同椭圆率巷道冲击破坏演化规律。结果表明:试样峰值应力及轴向变形量会随椭圆率的增大呈现先增大后减小的趋势,椭圆率为1.25试样的峰值应力及轴向变形量最大;巷道破坏主要集中在边帮两侧,声发射三维定位也验证了这种破坏特征;扰动加载期声发射计数、能量突增,声发射b值突降,说明试样在扰动应力下产生了大尺度破坏。随着椭圆率的增加,声发射的最大计数、最大能量、b值下降幅度均呈现增加趋势。不同椭圆率试样声发射累计能量与时间均存在非线性关系,证明了冲击破坏的能量骤增原理。不同椭圆率试样红外云图和平均红外辐射温度在破坏时有明显的上升,其中椭圆率为1.25试样最为显著。试验结果为地下工程巷道断面防冲设计提供了理论支撑。

     

    Abstract: In order to study the influence mechanism of ellipticity on the impact damage characteristics of roadways, the multifunctional physical simulation test system for deep rockburst developed independently was used to carry out the impact damage test of elliptical roadways under the true three-dimensional conditions, and analyze the evolution law of impact damage of roadways with different ellipticity. The results show that: the peak stress and axial deformation of the sample will increase and then decrease with the increase of ellipticity, and the peak stress and axial deformation of the sample with an ellipticity of 1.25 is the largest; the damage of the roadway is mainly concentrated in the two sides of the side gangs, and the 3D localization of the acoustic emission verifies this kind of damage characteristic; the acoustic emission counts and energies of the perturbation loading period increase suddenly, and the b value of the acoustic emission decreases suddenly, which means that the sample produces the large-scale damage under the disturbing stress. large-scale damage. With the increase of ellipticity, the maximum counts, the maximum energy, and the decrease of b-value of the acoustic emission all show an increasing trend. The nonlinear relationship between the cumulative energy and time of the acoustic emission of the samples with different ellipticity proves the principle of sudden energy increase of impact damage. The infrared cloud map and average infrared radiation temperature of different ellipticity samples have obvious increase in damage, among which the ellipticity of 1.25 samples is the most significant. The test results provide theoretical support for the design of underground engineering roadway section to prevent rockburst.

     

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