Experimental study of directivity effect of rock interface under Brazilian splitting
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摘要: 為了研究硬巖與軟巖交界面方向對其破壞形式的影響,對含巖石-水泥砂漿(代替軟巖)交界面的組合試樣進行了多組加載角度的巴西劈裂試驗,獲得了不同交界面方向的組合試樣的"抗拉"強度,并利用顆粒流程序PFC2D研究了交界面的破壞機理.計算得到的"抗拉"強度隨交界面與加載方向夾角的增大而增大.當交界面平行于加載方向時,沿交界面發生劈裂破壞,計算得到的"抗拉"強度可認為是交界面的抗拉強度;當交界面與加載方向不平行時,發生更為復雜的拉-剪復合破壞.此外,為了進一步分析交界面的抗拉強度對破壞形式的影響,采用提高水泥用量和增大交界面粗糙度兩種方法增加交界面的抗拉強度,并進行了一系列試驗.試驗得到了含交界面的巴西劈裂試驗的典型破壞模式分布圖,對更好地理解硬巖與軟巖交界面的破壞形式具有指導意義.Abstract: A series of Brazilian split tests on rock-cement interface considering the effect of interface orientations were conducted to investigate the influence of hard rock-soft rock interface direction on failure behavior. The tensile strength for different interface orientations was obtained and failure mechanism of the interface was analyzed by the particle flow code PFC2D. The measured tensile strength increases as the interface-loading angle increases. The measured tensile strength can be considered to be equivalent to that of the interface if the interface orientation is parallel to the loading direction, because tensile failures occur along the interface. Mixedmode failures occur if the interface is not parallel to the loading line. In addition, another series of Brazilian tests were conducted to investigate the influence of the interface tensile strength on failures by increasing the cement dosage and roughening the rock surface. Based on the results, a diagram of the failure mode distribution marked with the typical failure patterns from the Brazilian test results for the rock-cement interface was developed. These findings provide a better understanding of the failure modes of the hard rock-soft rock interface.
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Key words:
- rock mechanics /
- rock interface /
- Brazilian split /
- fracture modes
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參考文獻
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