煤壁片帮是制约大采高软煤综采工作面安全、高效回采的主要因素之一。基于淮南矿区A组煤、B组煤煤系地层禀赋及下保护层开采生产条件，针对潘二矿11224工作面煤壁片帮破坏特点，采用现场实测、物理模拟、理论分析、工业试验等方法，研究了多关键层结构跨煤组远程下保护层开采覆岩采动裂隙发育规律和被保护层大采高软煤综采工作面煤壁失稳力学过程，揭示了回采前已受采动影响的煤壁片帮机理并提出控制措施。结果显示:① 被保护层煤壁破裂形式主要为不规则滑移体沿破裂面的滑移运动，同时伴有区域多发性及倾向蔓延性，片帮迹线观测到贯穿煤层的节理弱面;② 物理模拟显示，受下保护层开采影响，远程被保护层11224工作面处于覆岩“三带”中弯曲下沉带内，并出现大量随机分布的法向节理裂隙;③ 薄板模型极限挠度分析显示，采高、关键层空间结构、垮落带和断裂带岩层碎胀系数是决定“三带”发育高度的主控因素，理论计算所得“三带”发育特征与物理模拟一致;④ 基于煤壁片帮形式和受扰动影响特征，建立被保护层煤壁单元受力简化模型，给出考虑围压作用任意形态三棱柱体剪切破坏判据;⑤ 三棱柱体破裂后形成滑移体，主控弱面控制滑移体的摩擦滑动，提出滑移体沿结构面摩擦滑动失稳判据;⑥ 提高支架阻力和护帮力、采用“棕绳+注浆”柔性支护以及工字钢辅助铺网加强支架支护，可显著提高煤壁单位稳定性。

Coal wall spalling is one of the main factors restricting the safety and high efficiency of fully mechanized coal face. Based on the characteristics of the coal-bearing strata of Group A and Group B coal in Huainan Mining Area and the production conditions of the lower protective layer,the field test,physical simulation,theoretical analysis,in- dustrial test,etc. are adopted for studying the damage characteristics of the coal wall spalling at the 11224 working face in Pan’er Coal Mine. The development law of overburden mining fissures in the remote protective layer of multi-critical layer structure and the coal wall instability in the fully mechanized mining face of the large mining height soft coal are studied,the mechanism of coal wall spalling affected by mining before mining is revealed and the control measures are put forward. The results show that:① The coal wall fracture of the protected layer is mainly composed of irregular sliding motion along the fracture surface,accompanied by regional multiple and prone sprawl. ② Physical simulation shows that affected by the mining of the lower protective layer,the working face of the remote protected layer 11224 is located in the “three belts” of overlying rock in the bending subsidence zone,and a large number of randomly distrib- uted normal joints and fractures occur. ③ The ultimate deflection analysis of thin plate model shows that mining height,the spatial structure of key strata,the collapse and expansion coefficient of rock strata in caving zone and frac- ture zone are the main controlling factors to determine the development height of “three zones”,and the development characteristics of “three zones” obtained by theoretical calculation are consistent with physical simulation. ④ Based on the form of the coal wall panel and the characteristics affected by the disturbance,the simplified model of the coal wall unit of the protected layer is established,and the shear failure criterion of any triangular prism body with confining pressure is given. ⑤ The slip body is formed after the fracture of the triangular prism. The main control weak surface controls the friction and sliding of the slip body,and the criterion of friction and sliding instability of the slip body a- long the structural surface is proposed. ⑥ The stability of coal wall unit can be significantly improved by increasing the support resistance and retaining force,adopting the “ brown rope+grouting” flexible support and the i-steel auxiliary paving network to strengthen the support.