Several derivative disasters such as ground pressure disasters and methane explosions can be caused by the hard roof in coal mines. For limestone roofs with fine integrity and extreme hardness, collapse is difficult and the effect of conventional roof control methods is limited. Acidizing reformation is an effective way to weaken the strength of roof strata based on acid-rock reaction. In this study, the rock strength damage law and acid reaction characteristics were tested by the limestone acidification experiment. Besides, the strength degradation mechanism of limestone under the acidity effect was analyzed. The results show that the acid corrosion characteristics of limestone are obvious, as numerous mineral grains generate voids under the effects of acid corrosion, and more defects are formed inside. The acid-rock reaction is the most intense at the early stage and then gradually reaches dynamic equilibrium, and the acid corrosion rate of limestone is 4.24% (10% HCl, 360 min). The hard limestone is damaged after acidification. Furthermore, the internal cracks can be induced to rapid initiation and unstable propagation under load, which reduces the strain required for rock failure by 33.33%. The failure morphology is more complicated, and the uniaxial compressive strength and elastic modulus decrease by 52.42% and 34.44% respectively. The strength weakening of hard roof after acidification is due to the defects such as intergranular cracking caused by the corrosion of rock crystals under acidity effect, which accelerate the initiation and propagation of internal cracks with external force. Macroscopically, acidification induced the deterioration of rock mechanical properties by reforming the roof structure. The feasibility of acidizing reformation method to control hard roof is confirmed in this study.

煤矿硬顶板可引发多种衍生灾害，如地压灾害和瓦斯爆炸。对于整体性好、硬度极高的石灰石屋面，倒塌困难，传统屋面控制方法的效果有限。酸化改造是基于酸岩反应弱化顶板强度的有效途径。本研究通过石灰石酸化实验测试了岩石强度破坏规律和酸反应特性。此外，分析了石灰石在酸度作用下的强度退化机理。结果表明，石灰石的酸蚀特征明显，大量矿物颗粒在酸蚀作用下产生空隙，内部形成的缺陷较多。酸岩反应前期最为激烈，随后逐渐达到动态平衡，石灰石的酸蚀率为4.24%（10% HCl，360 min）。酸化后坚硬的石灰石被破坏。此外，在载荷作用下，内部裂纹可被诱导快速萌生和不稳定扩展，从而将岩石破坏所需的应变降低了 33.33%。破坏形态更为复杂，单轴抗压强度和弹性模量分别下降52.42%和34.44%。酸化后硬顶板强度减弱是由于酸化作用下岩石晶体腐蚀引起的晶间开裂等缺陷，在外力作用下加速了内部裂纹的萌生和扩展。宏观上，酸化通过改造顶板结构引起岩石力学性能的恶化。本研究证实了酸化改造方法控制硬顶的可行性。