以大倾角煤层下分层复采破碎顶板注浆改性为研究对象，结合潘四东矿3、1合并煤层分层开采工程地质条件，建立了5种粒径级配注浆固结体试样模型，开展了基于CT原位扫描加载的单轴压缩试验，研究了粒径级配对固结体强度特征、裂隙演化、声发射信号与微观形貌特征的影响规律。研究结果表明：① 随粒径级配增大，固结体内部孔隙、裂隙等缺陷受岩块与浆液基体间错位运动影响，形成了大规模剪切带，导致固结体单轴抗压强度逐渐减小，6～8 、8～10 mm粒径级配固结体受大粒径岩块影响，早期应力波动明显，破坏形式呈现出由贯穿张拉破坏、张拉−剪切复合破坏向剪切破坏转变。② 随粒径级配增大，水化产物（AFt与C–H–S）未形成交错网状致密结构充填岩块间孔隙，导致固结体整体强度降低；加载过程中岩块端部产生应力集中，剪切带增大，声发射活动提前且更加频繁，高值振铃计数增多，累计振铃计数增速升高。③ CT扫描显示加载过程中固结体破坏主裂隙主要发生在岩块与浆液基体胶结面，极少出现穿岩扩展；随粒径级配增大，固结体内部较多小裂隙扩展贯通成大开度裂隙，裂隙数目减少，其中0～2、4～6、8～10 mm粒径级配固结体破坏后裂隙体积V≤0.01 mm³的裂隙数目占比分别下降9.5%、1.6%、4.0%，V>10 mm³的裂隙数目占比分别提升0.1%、3.5%、4.9%；裂隙灰度值增加，裂隙体积占比增加，形成了更加复杂的裂隙网络。基于试验结果提出了破碎顶板钻孔注浆施工与铺网方案，为大倾角煤层下分层复采顶板稳定控制提供理论基础。

The study was conducted on modification of grouting of broken roof under stratified mining in a steeply dipping coal seam. Considering the geological conditions of stratified mining in the merged coal seams 3 and 1 at the Pansidong Mine, five types of particle size gradation of grouting reinforcement body models were established, a single-axis compression test based on CT in situ scanning was carried out, and the effects of particle-sized paired reinforcement body strength characteristics, crack evolution, acoustic emission signals and micromorphological characteristics were studied. The study showed that: ① With the increase of particle size grading, defects such as pores and cracks in the reinforcement body are affected by the dislocation of the rock and plasma matrix. Large-scale shear belts have been formed, leading to a gradual decrease in the single-axis pressure resistance of the reinforcement body. The 6～8mm and 8～10mm particle size grades of reinforcement body are affected by large particle size rocks, and early stress fluctuations are evident. The form of destruction shows a transition from cross-strait destruction, a combination of slash-slash destruction and a slash destruct. ② With the increase of particle size gradation, the hydrated products (AFt and C–H–S) do not form interlaced network structure to fill the pores between the blocks, which leads to the decrease of the overall strength of the reinforcement body. During the loading process, the end of the rock generates concentrated stress, the cut band increases, the sound emission activity is earlier and more frequent, the high-value vibration count increases and the cumulative vibration count grows faster. ③ The CT scan shows that the main fracture of the reinforcement body occurs mainly at the cementation surface between the rock mass and the grout matrix, and rarely extends through the rock. With the increase of particle size gradation, more small cracks in the reinforcement body expand into large opening cracks, and the number of cracks decreases. After the destruction of 0～2 mm, 4～6 mm and 8～10 mm particle sizes of reinforcement body, the proportion of the crack volume V ≤ 0.01 mm³ decreased by 9.5%, 1.6%, 4.0%, and the proportion of cracks V > 10 mm³ increased by 0.1%, 3.5%, 4.9%. The graying value of the crack increases, and the proportion of the crack volume increases to form a more complex crack network. Based on the test results, the drilling and grouting construction and netting scheme of broken roof are proposed, which provide a theoretical basis for the stable control of broken roof under stratified mining in a steeply dipping coal seam.