CCTEG Coal Mining Research Institute
Coal Mining and Designing Branch, China Coal Research Institute
Coal Mining and Designing Department, Tiandi Science and Technology Co., Ltd.

为获取不同岩性的煤层底板采动破坏特征，建立了不同内摩擦角对岩体强度影响的莫尔圆解，构建了采场端部最大底板破坏深度/采空区最大底板破坏深度的比值与内摩擦角的关联公式；运用FLAC3D数值模拟软件，分析了不同岩性条件下的煤层底板塑性区、最大剪应力、弹性应变能分布特征；从能量积聚与耗散的角度，建立了煤层底板采动破坏形态的概化模型；最后，结合平朔19110工作面底板实测数据进行验证。研究结果表明，超前支承压力作用下底板岩性为软弱岩体易发生剪切破坏，而未发生剪切破坏的中硬岩或硬岩，在应力卸荷作用下仍存在进一步破坏的可能性；随着煤层底板岩体内摩擦角的不断增大，煤层底板采动破坏范围的最大值将逐渐由采场端部向采空区后方转移；与煤层底板岩性为中硬岩或硬岩相比，岩性为极软岩或软岩的煤层底板岩体在煤壁附近剪应力和弹性应变能存在明显的衰减，并向深部转移，导致采场端部塑性区范围较明显；将煤层底板采动破坏区域划分为能量释放区、能量承载区、能量平衡区，与煤层底板岩性为软弱或极软弱类型相比，中硬岩或硬岩类型下的煤层底板能量释放区分布范围较小甚至缺失，主要通过能量承载区和能量平衡区实现采动扰动能量的平衡。现场实测发现煤层底板岩性为细砂岩、灰岩等、未发生剪切破坏的坚硬岩体，采动卸荷作用下进一步发生破坏，并呈现出由剪切破坏转变为剪切−拉伸变形复合破坏的特征。

In order to obtain the mining failure characteristics of coal seam floor with different lithology, the Mohr circle solution of the influence of different internal friction angles on the strength of rock mass is established, and the correlation formula between the ratio of the maximum floor failure depth at the end of the stope to the maximum floor failure depth in the goaf and the internal friction angle is constructed. Using FLAC3D numerical simulation software, the distribution characteristics of plastic zone, maximum shear stress and elastic strain energy of coal seam floor under different lithology conditions are analyzed. From the perspective of energy accumulation and dissipation, the generalized model of mining failure mode of coal seam floor is established. Finally, the measured data of 19110 working face at Pingshuo mine area is verified. The results show that under the action of advance abutment pressure, weak rock is prone to shear failure, while the medium hard rock or hard rock without shear failure still has the possibility of further failure under the effect of mining unloading. It is found that with the increase of internal friction angle of coal seam floor rock, the maximum value of mining failure range of coal seam floor will gradually shift from the end of stope to the rear of goaf. Compared with the lithology of medium hard rock or hard rock in coal seam floor, the shear stress and elastic strain energy of coal seam floor rock mass with extremely soft rock or soft rock have obvious attenuation near the stope and transfer to the deep part, resulting in an obvious plastic zone at the end of the stope. The mining failure area of coal seam floor is divided into energy release area, energy bearing area and energy balance area. Compared with the weak or extremely weak coal seam floor rock, the distribution range of energy release area of medium hard or hard coal seam floor rock is smaller or even missing, mainly through energy bearing area and energy balance area to achieve the balance of mining disturbance energy. Through field measurement, the failure mode of coal seam floor has been verified. Under the action of mining unloading, the coal seam floor is further damaged, the lithology of the coal seam floor is fine sandstone, limestone and other hard rock mass. The coal seam floor changed from shear failure to shear-tensile deformation composite failure.

国家自然科学基金资助项目(51704158, 51874177); 天地科技股份有限公司开采事业部科技创新基金资助项目(TDKC-2022-QN-03)

张风达. 煤层底板采动破坏机制的岩性效应研究[J]. 煤炭科学技术，2023，51（11）：166−178.

ZHANG Fengda. Study on lithologic effect of mining-induced failure mechanism of coal seam floor[J]. Coal Science and Technology，2023，51（11）：166−178.