岩体突水通道形成过程中应力-渗流-损伤多场耦合机制

突水通道形成的渐进性破坏过程是煤矿突(透)水机理研究的关键问题,采动扰动和地下水双重作用下岩体的持续渗流-损伤行为导致破裂通道最终形成.采用可考虑地下水作用下岩体拉剪和压剪双重破坏准则的计算程序,真实再现承压含水层与巷道之间隔水岩体的采动裂隙萌生、扩展、贯通直至破裂通道形成的灾变演化过程,通过对岩体应力场、渗流场和损伤场的耦合演化过程进行分析,实现了对突水通道形成轨迹的准确定位,揭示了突水通道形成过程中岩体应力-渗流-损伤的耦合机制.数值实验结果表明:采动影响下持续的应力-渗流-损伤耦合作用诱发岩体强度降低导致突水通道最终形成,隔水岩体历经了群裂纹萌生、扩展和贯通的渐变过程；通道贯通前,岩体破裂损伤能量激增,通道部位岩体剪应力急剧下降,渗透系数和流量则急剧上升,各物理场均孕育了不同程度的突水前兆信息.

Multi-Field Coupling Mechanism of Seepage Damage for the Water Inrush Channel Formation Process of Coal Mine

Gradualness failure formation process of water inrush channel is the key problem for study on water inrush mechanism of mining,sustained coupling effect of seepage damage induced by double effect of groundwater and mining disturbance finally leads to the formation of rupture channel.Calcula-tion program considering the double failure criterion of tension shear and compression shear for rock mass under the groundwater effect,in order to get the catastrophe evolution process of crack initiation,propagation,transfixion and channel formation for surrounding rock of water insulation under mining influence,coupling effect of stress and seepage damage for the catastrophe evolution process has been analyzed,and the formation trajectory of water inrush channel has been accurately located.Based on the calculation results of numerical experiment,water inrush channel finally forms due to strength de-creased of rock mass induced by the sustained coupling effect of stress and seepage damage,and sur-rounding rock of water insulation experiences group crack initiation,propagation and transfixion,when the water inrush channel of group cracks suddenly connects to each other,rupture damage energy of rock mass increases sharply,shearing stress of rock mass near the channel suddenly drops,permeability coefficient and discharge increase sharply,precursor information of water inrush has been pregnant with the different physical field of rock mass at the channel path.