晋城无烟煤结构面剪切参数的试验测定与估算方法

Test and estimation on the shear parameters of structural plane from Jincheng anthracite coal

  • 摘要: 为研究晋城无烟煤的煤体结构面剪切强度及相关参数,通过对取自寺河煤矿3号煤层的含结构面煤体试样进行不同法向应力下的直剪试验,并对结构面形貌进行三维摄影测量,得到了剪切强度的试验值及估算值。试验结果表明:在低法向应力水平下,煤体结构面的法向刚度取值为13. 0~39. 2 GPa/cm,剪切刚度取值为3. 1~26. 6 GPa/cm,中等法向应力水平下,煤体结构面的法向刚度取值为13. 8~62. 0 GPa/cm,剪切刚度取值为4. 3~18. 2 GPa/cm,煤体结构面黏聚力平均值0. 67 MPa,峰值摩擦角平均值37°,同时结构面法向刚度、剪切刚度、剪切强度都随法向应力增大而增大,实验结果可为数值模拟中参数的选取提供一定参考。对比估算剪切强度值与试验剪切强度值表明,运用JRC-JCS模型能较好的预测煤体结构面剪切强度。

     

    Abstract: In order to study the shear strength and related parameters of coal structural planes from Jincheng an-thra- cite coal,some direct shear tests under different normal stresses were carried out on coal samples with structural planes from No,3 coal seam of Sihe mine,and also the three dimensional photogrammetry of the structural surface topography was carried out. The tests obtained some experimental values and estimated values. The test results show that under a low normal stress level,the stiffness range of coal structural plane is 13-39. 2 GPa / cm,and the range of shear stiffness is 3. 1-26. 6 GPa / cm. Under a moderate normal stress level,the stiffness range of coal structural plane is 13. 8-62. 0 GPa / cm,and the range of shear stiffness is 4. 3-18. 2 GPa / cm,The average cohesion of coal structural plane is 0. 67 MPa,and the average peak friction angle is 37 degree. With the increase of normal stress,the normal stiffness, shear stiffness and shear strength of the structural plane also increase. The test values provide a reference for the pa- rameters in numerical simulation. Through the comparison between calculated shear strength and experimental shear strength,the JRC-JCS model can be used to predict the shear strength of the structural plane.

     

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