注水煤体应力能V-f转化与释放机理研究

The V-f transforming and releasing mechanism study on stress energy of coal mass after water injection

文章分析了在煤层注水湿润后煤体弹性能的转化与消耗过程,给出在湿润状态下能量由体变弹性能向形变弹性能转化进而自耗释放的理论模型。指出在坚硬干燥煤体中,注水后在水压力和毛细力的切割作用下,裂隙大量扩展,丰富了自由裂隙,产生更多的裂隙启发(裂隙切口),使原来近似的刚性煤体变成由裂隙分割的块体组成的组合体或半组合体。裂隙中水的粘滞作用及水分子吸附力使块体间粘性结合、刚度降低、形变增大。煤体形变弹性能自身消耗释放的形式有3种:产生剪应力导致自由裂隙间错动摩擦;强度降低,使裂隙启发被劈裂成自由裂隙;湿润煤体蠕变性增强,产生整体性移动作功。初步给出能量消耗的量化表达式。通过这一理论,能建立煤层注水湿润度与冲击地压灾害发生的更直接的关系,使进一步量化该关系成为可能。从更深层次解释煤层注水防治冲击地压的机理。

Analyzing the process of transformation and consumption of coal's elastic energy after water injection, this paper gives the theoritical model which the energy transforms from volume changing elastic energy to deformation one in the wetting situation, and points out the fissures will extend under water pressure and capillary force after water injection. Because of the enriched free fissures nick, the inflexible coal will change from whole block divided by fissures to assemblage or half-assemblage blocks, and rigidity reduces and deformation increases. There are three releasing forms when the elastic energy is consumed. They are as follows:shear stress results in strain-slip friction amoung free fissures; the fissure nicks among coal mass are cleaved into free fissures; the strengthened creep property of wetted coal mass moves and produces power. This theory may establish the relation between rockburst hazard and the wetted extent. So it is possible to quantify this relation further and interpret the mechanism of water injection to prevent rockburst.