为研究底煤厚度对巷道底板冲击地压的影响机制，以厚度为3 m以下的薄及中厚底煤为分析对象，基于掘进巷道底板冲击特征并采用理论分析，建立底板煤岩层叠体梁挠曲破坏力学模型，底板煤岩层挠曲变形曲线具有同步异幅的发展特性。公式计算表明，随着底煤厚度的增加，底煤积聚弹性能逐渐增加，增加梯度逐渐平缓，其与底煤厚度的4次方倒数具有负相关关系。通过FLAC3D数值模拟开展底板煤岩主应力、塑性区及弹性能分析，结果表明，巷道底板岩层是主要的冲击动力能贮存体，而底煤是主要的动力释放显现体;底煤通过影响底板潜在冲击启动区、潜在冲击能量传递区、潜在冲击地压显现区的范围、贮存能量以及3者之间的依存位置，进而影响底板煤岩层之间的能量储存与传递机制，从而影响底板冲击地压的形成过程。底煤相对于底板岩层具有较弱的弹性能储存能力，底煤厚度是影响底煤储存弹性能量的关键因素，底煤厚度通过影响底煤与底板岩层之间的弹性能量传递能力从而影响底板冲击危险性。随着底煤厚度的增加，底板冲击危险性逐渐增加，增加梯度逐渐降低;当底煤厚度增加到2 m时，底煤厚度的再增加对底板冲击危险性无明显叠加影响，呈现出底煤厚度对底板冲击危险性影响的阈值效应。留底煤底板卸压时，应针对底板岩层采取解危措施，阻断应力传递路径，减小底板能量积聚，从而降低底板冲击危险性。研究成果在现场进行了应用分析，通过钻屑法监测显示解危效果良好。

For thin and medium-thick bottom coal layer with thickness of less than 3 m,in order to study the influence mechanism of bottom coal layer thickness on floor rock burst,based on the impact characteristics of floor in excavation roadway and theoretical analysis,the mechanical model of deflection failure of coal-rock laminated beam of floor was established.The deflection deformation curve of floor coal and rock has the development characteristics of synchronization and different amplitudes.The formula calculation shows that with the increase of bottom coal layer thickness,the accumulation elastic energy of bottom coal layer gradually increases,and the increase gradient gradually becomes gentle,which has a negative correlation with the reciprocal of the fourth power of coal thickness.The FLAC3D numerical simulation was used to analyze the main stress,elastic-plastic zone and elastic energy.The results show that the floor rock layer of roadway is the main impact dynamic energy storage body,and the bottom coal layer is the main power release manifestation.The bottom coal layer affects the energy storage and transfer mechanism between the bottom coal and rock by affecting the scope of the potential rock burst start-up zone,the potential energy transfer zone,the potential rock burst occurrence zone,the stored energy,and the dependence between the three zones.This will affect the formation process of the floor rock burst.Bottom coal layer has a weak elastic energy storage capacity relative to the floor rock layer.The thickness of bottom coal layer is a key factor affecting the storage of elastic energy of bottom coal.The thickness of bottom coal layer affects the floor rock burst hazard by affecting the elastic energy transfer ability between coal and rock.With the increase of bottom coal layer thickness,the floor rock burst hazard gradually increases and the gradient gradually decreases.When the thickness of bottom coal layer increases to 2 m,the increase of bottom coal layer thickness has no obvious superimposed effect on the floor rock burst hazard,showing the threshold effect of bottom coal layer thickness on the floor rock burst.When the pressure of floor with bottom coal layer is relieved,it is necessary to take measures to eliminate the danger of the floor rock,block the stress transmission path,reduce the energy accumulation of the floor,and thus reduce the risk of floor rock burst.The application of the research results was analyzed and validated on site.Monitoring by the method of drill bits showed that the effect of eliminating the danger was good.