高应力下含瓦斯原煤三轴压缩力学特性研究

发布时间：2018-02-27 07:21

本文关键词： 采矿工程高应力含瓦斯原煤三轴压缩有效围压瓦斯压力　出处：《岩石力学与工程学报》2017年02期 　论文类型：期刊论文

【摘要】：利用改制后的煤岩吸附渗透力学耦合试验系统,以淮南矿区-780 m标高B10煤层的原煤样作为研究对象,进行高应力下含瓦斯原煤常规三轴压缩力学特性的研究。结果表明:(1)含瓦斯原煤偏应力轴向应变曲线主要有弹性、屈服、破坏或峰后软化段构成。其中,弹性段连续、光滑性较差,多呈现出应变“软化硬化”的波动起伏特点。(2)峰后脆性破坏特征明显,且在相同初始瓦斯压力下,随着初始有效围压的升高,脆性向延性转化的趋势较弱;而在相同初始有效围压下,初始瓦斯压力越大,脆性破坏特征则越显著。(3)偏应力侧向应变曲线与轴向相比,峰前连续、光滑性更好,且几乎均呈线弹性;而峰后变化则趋同。(4)偏应力体应变曲线,在低有效围压下表现出扩容机制,且始于峰前;而在高有效围压下,则从峰前越至峰后,始终向右延展,呈现出体积不断收缩的趋势,且瓦斯压力越大,收缩特性越显著。(5)在相同有效围压下,随着瓦斯压力的增加,峰前轴向、侧向应变增加的速率,以及峰值强度、泊松比均呈增大趋势;而弹性模量则呈降低趋势。(6)相同瓦斯压力下,随着有效围压的增加,峰前轴向、侧向应变增加的速率,以及泊松比均呈降低趋势;而峰值强度、弹性模量则呈增大趋势。(7)随着围压或瓦斯压力分别升高,峰值强度均呈线性增大趋势,煤样破坏模式以剪切破坏为主,且强度参数黏聚力和内摩擦角分别为14.02 MPa,25.93°。
[Abstract]:By using the modified coal and rock adsorption and permeability mechanical coupling test system, the raw coal samples of -780 m elevation B10 coal seam in Huainan mining area were taken as the research object. The mechanical properties of conventional triaxial compression of gas-bearing raw coal under high stress are studied. The results show that the axial strain curve of gas-bearing raw coal is mainly composed of elastic, yielding, failure or post-peak softening section, in which the elastic section is continuous. The smoothness is poor, most of them show the fluctuating and undulating characteristic of strain "softening and hardening". The brittle failure characteristic after peak is obvious, and under the same initial gas pressure, with the increase of initial effective confining pressure, the tendency of brittleness to ductility is weaker; Under the same initial effective confining pressure, the higher the initial gas pressure is, the more obvious the brittle failure is. (3) compared with the axial direction, the deformation stress and lateral strain curve are continuous in front of the peak, better in smoothness, and almost all in linear elasticity. However, the post-peak variation tends to be the same. (4) the deformation stress and strain curve shows a mechanism of expansion under low effective confining pressure, which begins before the peak, while at high effective confining pressure, it always extends to the right from the front of the peak to the back of the peak. Under the same effective confining pressure, with the increase of gas pressure, the rate of increase of peak forward axial direction, lateral strain, and peak strength are increased with the increase of gas pressure. Poisson's ratio showed an increasing trend, while elastic modulus showed a decreasing trend.) under the same gas pressure, with the increase of effective confining pressure, the rate of increase of peak forward axial strain, lateral strain and Poisson's ratio all showed a decreasing trend, while the peak strength, The elastic modulus shows an increasing trend.) with the increase of confining pressure or gas pressure, the peak strength of coal samples increases linearly. The failure mode of coal samples is mainly shear failure, and the cohesion of strength parameters and the angle of internal friction are 14.02 MPA ~ (25.93 掳).
【作者单位】：中煤科工集团西安研究院有限公司;
【分类号】：TD322

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