基于3D打印的深部开采中煤矿岩体结构面剪切特性研究

Shear characteristics of coal mine rock mass structural face in deep mining based on 3D printing

  • 摘要: 【目的及方法】深部岩体处于极其复杂的应力环境中,但随着开采深度的不断增加,深部的围岩应力重新分布,造成部分岩体产生高应力显现。鉴于此,针对同一类岩石试件,利用3D打印技术,制备了4组不同粗糙度系数的结构面剪切试件,进行了不同法向应力下结构面剪切实验。【结果】结果显示,结构面破坏形式基本分为3个阶段。当法向应力为2.3 MPa时,岩体较为完整,属于剪切滑移破坏。【结论】当法向应力小于16.1 MPa大于2.3 MPa时,结构面剪切时沿着起伏体中部发生破坏,为拉剪混合破坏;当法向应力为20.7 MPa时,试件上下覆岩体破坏严重,为轴向劈裂破坏;当法向应力为20.7 MPa时,粗糙度系数并不会对结构面峰值剪切强度产生较大影响,并且在同一法向应力下,粗糙度系数的改变主要影响结构面产生裂隙的数量,为判断施加于试件法向应力的大小提供了参考。

     

    Abstract: The deep rock mass is in an extremely complex stress environment,but with the continuous increase of mining depth,the stress of the surrounding rock in the deep part is redistributed,resulting in high stress behavior in some rock masses. We use 3D printing technology to prepare four sets of structural face shear specimens with different roughness coefficients for the same type of rock specimens,and conduct structural face shear experiments under different normal stresses.The results show that the failure mode of structural face can be basically divided into three stages. When the normal stress is2. 3 MPa,the rock mass is relatively intact and belongs to shear slip failure; When the normal stress is less than 16. 1 MPa and greater than 2. 3 MPa,the structural face undergoes shear failure along the middle of the undulating body,which is a mixed tensile shear failure; When the normal stress is 20. 7 MPa,the overlying rock mass of the specimen is severely damaged,resulting in axial splitting failure; As the normal stress increases,when the normal stress is 20. 7 MPa,the roughness coefficient does not have a significant impact on the reduction of the peak shear strength of the structural face. Moreover,under the same normal stress,the change in roughness coefficient mainly affects the number of cracks generated in the structural face,providing a reference for determining the magnitude of the normal stress applied to the specimen.

     

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