非均质性对岩石Ⅰ型断裂特性影响的数值模拟研究

Numerical simulation on effect of heterogeneity on modeΙfracture characteristics of rock

由于岩石的抗拉强度远低于其抗压强度,其对拉伸荷载比压缩荷载更加敏感。因此研究拉伸荷载下岩石的断裂特性对于深入理解岩石的破坏机制具有重要意义。本研究中,作者利用岩石破坏过程分析系统RFPA,对不同均质度岩石Ⅰ型裂纹扩展过程展开了研究。随着岩石均质程度的提高,裂纹逐渐向韧带区域集中,并且裂纹分叉逐渐减少,主裂纹趋于平滑。当均质度在1.5~5区间内,岩石裂纹行为和力学性能受均质度的影响比较严重。当均质度大于30时,二者基本不受均质度差异的影响,此时岩石可基本上认为是均质材料。细观尺度上岩石力学性质分布影响了岩石整体和局部强度,进而影响了裂纹行为。

Rock is more sensitive to tensile loading than compressive loading,since the tensile strength of rock is much lower than compressive strength.The fracture characteristics of rock in the tensile state are of great significance to the understanding of rock failure mechanisms.To this end,we have conducted numerical simulation researches on modeⅠcracking process of rock with varying homogeneity,using the Realistic Failure Process Analysis program.With the increase of homogeneity,cracks are concentrating to the ligament area with a decreasing number of crack bifurcations,and the main crack path is becoming smooth.Crack behaviors and mechanical properties are influenced significantly when the homogeneity index is in the range of 1.5 to 5.When the homogeneity index is greater than 30,they are not affected by rock homogeneity and the rock can be considered as essentially homogeneous.It is considered that the global and local strengths are affected by the distribution of rock mechanical properties at mesoscale,which influence the crack behaviors and mechanical characteristics.