基于起伏形态特征的节理岩石峰值剪切强度准则

Peak shear strength criterion for rock joints based on undulating characteristics

运用RYL-600剪切流变仪对不同法向应力下的人工花岗岩试件进行多次剪切试验,得到不同法向应力下的剪切应力-剪切位移曲线,并运用TALYSURF CLI 2000对剪切前后节理面进行形貌扫描,得到节理面3维形貌图。通过试验方法得到节理剪切强度与形貌的关系。在试验结果的基础上,考虑起伏形态参数节理面整体轮廓角加权平均值[θ_p]_x对剪切强度的影响,并对Barton准则进行修正,将由修正的Barton准则计算的剪切强度与试验结果进行对比。研究结果表明:[θ_p]_x随着剪切次数增加而减小;修正的Barton准则计算结果与试验结果较吻合,能较好地预测节理剪切强度。

Shear tests of artificial granite joints under different normal stresses were conducted with RYL-600,and the curves of shear stress versus shear displacement under different normal stresses were obtained. The 3D scanning images were obtained before and after each shear tests under different normal stresses with TALYSURF CLI 2000.Relationships between morphology of jointed rock surfaces and shear strength were studied experimentally. Based on the experiment, the undulating characteristics of joint surfaces were analyzed. Barton criterion modification was made by considering undulating characteristic [θ^-p ]x . Comparison among the experimental data, Barton criterion and modified Barton criterion were made to evaluate the accuracy of the modified criterion. The results show that the average of the mean profile angles [θ^-p ]x decreases with the increase of the times of shear tests. The shear strength values calculated by the modified Barton criterion agree well with the testing results and the shear strength of jointed rock can be predicated by the new criterion.