基于叠梁应力势函数的煤层顶板破坏研究

Study on coal seam roof failure based on stress potential function of laminated beams

为了研究煤矿开采中煤层顶板的破坏程度及破坏特征,将直接顶与间接顶简化为遍布水平节理与垂直节理的叠梁模型,引入弹性力学中的应力势函数,结合摩尔-库伦强度准则分析煤层顶板的破坏域尺寸及形状;并使用3DEC软件进行进一步验证。结果表明:煤层顶板的破坏可分为由水平节理造成的离层以及由垂直节理造成的断裂;离层破坏域呈上陡下平的“类双曲线”分布、断裂破坏域呈拱形分布;随着间接顶弹性模量的增大,直接顶的离层宽度、高度明显降低;随着间接顶层高的增加,间接顶的断裂高度占比逐渐降低,离层宽度逐渐提升。这说明:当层高确定时,煤层顶板应力向硬岩转移,造成更大的破坏域面积;当岩性确定时,较大的间接顶层高可以显著降低断裂高度,转而提高离层破坏宽度。可以为煤层顶板破坏领域的工程实际问题提供理论依据。

In order to study the degree and characteristics of roof failure in coal mining, the immediate roof and main roof are simplified into a laminated beam model with horizontal joints and vertical joints, the stress potential function in elasticity is introduced, combining with Moore-Coulomb strength criterion, the size and shape of failure zone of coal seam roof are analyzed;finally, 3 DEC software was used for further verification. The results show that: the roof failure of coal seam can be divided into separation layer caused by horizontal joint and fracture caused by vertical joint;the stratification failure domain presents “hyperbolic” distribution, while the fracture failure domain presents arched distribution;with the increase of the elastic modulus of main roof, the separation width and height of direct roof decrease obviously;with the increase of the main roof height, the proportion of the fault height in the indirect top decreases gradually, and the width of separation increases gradually. The results indicate that, when the layer height is determined, the roof stress of coal seam transfers to hard rock, resulting in a larger failure area;when lithology is determined, higher main roof height can significantly reduce the fault height and in turn increase the separation failure width. This research can provide relevant theoretical basis for engineering practical problems in the field of roof failure of coal seam.