背斜构造成因机制及冲击地压灾变机理研究

Formation mechanism of anticline structure and its disastrous mechanism of rock burst

针对背斜构造诱发冲击危险相关特点,基于材料力学及Winkler弹性地基理论,建立了背斜构造成因力学模型,导出了该模型挠度、弯矩及应变能理论解;通过UDEC数值试验,揭示了背斜轴影响下工作面煤壁前方支承压力分布特点,研究了采动影响下支承压力峰值处盈余能量E0-Ec值变化规律。结果表明:背斜构造的形成受到多重因素共同作用,煤体埋深、上覆岩层容重、特征系数及地基系数越小,构造力偶越大,背斜越易形成;背斜不同位置处应变能不同,构造力偶越大、抗弯刚度越小,微段dx处应变能越大;随着工作面不断推进,煤壁前方支承压力与背斜轴高构造应力呈现出"连接-叠加-分离"现象;工作面越靠近背斜轴,支承压力峰值处盈余能量E0-Ec值越高,发生冲击危险的可能性就越大。

Aiming at characteristics of rock burst induced by anticline structure, based on material mechanics and theory of Winkler beam on elastic foundation, mechanical model of anticline genesis was establish, the deflection, bending moment and strain energy of the model were deduced. By using UDEC numerical simulation, distribution laws of advanced abutment pressure affected by anticlinal axis were revealed, and surplus energy of E0-Ec at the peak of abutment pressure were studied. Results show that the formation of anticline is influenced by multiple factors. The smaller the buried depth of coal seam, bulk density of overlying strata, characteristic coefficient and foundation coefficient, the larger the tectonic stress, and the easier anticline structure can be formed. In addition, strain energy changes with its locations in anticline structure. The larger the tectonic stress, the smaller the flexural rigidity, and the larger the strain energy in micro-segment dx. With the continuous advancing of working face, the phenomenon of ＂connection-overlay-separation＂ of advanced abutment pressure and high tectonic stress of anticlinal axis has been presented. Meanwhile, the closer the distance of working face to anticlinal axes, the larger the surplus energy at the peak of abutment pressure, and the greater the occurrence possibility of rock burst.