The stability of the sandwich composite structures formed by leaving coal pillar, roof rock and floor rock (RCF) is of great significance to safe production of coal mines. The failure of coal and rock is actually a state instability phenomenon driven by energy. In order to explore energy characteristics of RCF sandwich composite structures, uniaxial compression tests with different coal thicknesses were performed by numerical simulation tests. The test results show that strength and elastic modulus of RCF sandwich composite structures are lower than roof or floor rock single body and higher than coal single body when coal are taken different thicknesses. Main failure modes of coal and rock single bodies are cleavage, while main failure modes of RCF sandwich composite samples are shear. The peak strength and elastic modulus of RCF composite samples decrease with increasing coal thicknesses. The total input energy U, releasable elastic strain energy U_e and dissipative energy U_d all decrease first and then increase with increase of coal thickness. And a new damage constitutive model was established based on the dissipative energy and total input energy at peak strength, and damage evolution curve and equation of RCF composite samples were obtained. The study laid a foundation for the disaster evolution process of the RCF sandwich composite structures and mechanism of disaster time effect.

留下煤柱，顶板岩石和底板岩石（RCF）形成的夹心复合结构的稳定性对煤矿的安全生产具有重要意义。煤和岩石的破坏实际上是由能量驱动的状态不稳定性现象。为了探索RCF夹层复合结构的能量特性，通过数值模拟试验对不同厚度的煤进行了单轴压缩试验。试验结果表明，当采用不同厚度的煤时，RCF夹层复合结构的强度和弹性模量低于顶板或底板岩石单体，而高于煤单体。煤和岩石单体的主要破坏模式是劈裂，而RCF夹心复合材料样本的主要破坏模式是剪切。RCF复合材料样品的峰值强度和弹性模量随煤厚度的增加而降低。总输入能量U，可释放弹性应变能U _e和耗散能U _d均随煤厚度的增加先减小后增大。根据耗散能量和峰值强度下的总输入能量建立了新的损伤本构模型，得到了RCF复合材料试样的损伤演化曲线和方程。该研究为RCF夹芯复合结构的灾害演化过程以及灾害时间效应机理奠定了基础。