动压影响下断层构造应力场和能量场分布特征

Stress field and energy field distribution characteristics of faults under dynamic pressure

复杂地质构造尤其逆断层滑移失稳是诱发煤矿冲击地压的主要因素。为了深入研究冲击地压灾害的产生与断层属性之间的内在联系,以义马煤田F16逆冲断层为地质背景,结合千秋矿21221工作面概况,模拟了开采扰动对断层活化的影响规律,研究了断层落差、倾角和沿上下盘开采等因素对其滑移失稳的影响以及工作面开采过程中断层应力场和能量场的分布特征。研究结果表明:断层落差较小时,落差对断层的滑移影响可以忽略不计。但随着断层落差的增加,法向应力逐渐增大,切向应力先增大后减小,大落差断层比小落差断层更易发生滑移失稳;断层倾角的增加导致断层滑移量增大,法向应力先增大后减小,切向应力先减小后增大,断层倾角与断层滑移失稳呈正相关;工作面沿下盘开采更易诱发断层产生滑移甚至冲击地压。数值模拟结果显示,工作面过断层前,支承压力逐渐增加,过断层时保持平稳,过断层后先逐渐减小后逐渐增大;工作面前方能量场的应力集中区能量积聚现象明显,并与顶板能量积聚区始终贯通。由于卸压,采空区内能量降低较为明显,工作面上方的顶板应力得到释放,释放瞬间断层压力急剧增大,断层活化的可能性最大。

Complex geological structures,especially the reverse fault slip instability,are the main factors that induce the impact pressure of coal mines,In order to deeply study the intrinsic relationship between the impact of rock burst disaster and fault property,the F16 thrust fault of Yima coalfield is taken as the geological background,and the influence of mining disturbance on fault activation is simulated by combining the profile of No.21921 working face of Qianqiu Coal Mine.The effects of fault drop,dip angle and mining along the upper and lower plates on the slip instability and the distribution characteristics of the stress field and energy field in the discontinuous layer of the mining face were studied.The results show that when the fault drop is small,the influence of the drop on the slip of the fault can be neglected.However,with the increase of fault drop,the normal stress increases gradually,and the tangential stress first increases and then decreases.The large drop fault is more likely to slip instability than the small drop fault;the increase of fault dip angle leads to the increase of fault slip.The normal stress increases first and then decreases,and the tangential stress decreases first and then increases.The fault dip angle is positively correlated with the fault slip instability.The working face is more likely to induce slippage or even impact ground pressure along the lower mining.The numerical simulation results show that the support pressure increases gradually before the fault passes through the fault and remains stable after crossing the fault,and it remains stable after crossing the fault.After the fault,it gradually decreases and then gradually increases.Energy accumulation in the stress concentration area of energy field in front of the working surface is obvious.Energy accumulation phenomenon in stress concentration area distributed in front of the working surface is obvious and energy accumulation area of roof is always penetrated.However,due to pressure relief,the energy reduction in the gob is more obvious,stress on the roof above the working surface is released,and instantaneous fault pressure increases sharply,and the possibility of fault activation is the greatest.