基于UDEC-GBM的矿物晶粒解理特征对硬岩石破坏过程的影响

基于块体离散单元数值模拟方法（UDEC-GBM），以钾长石矿物颗粒为例，详细研究了矿物晶粒解理倾角、解理倾角围压效应及解理间距对硬质岩石力学性质、微观开裂过程及机理的影响，并探讨了解理特征在工程实际中可能带来的影响。数值研究结果表明:（1）晶粒解理具有明显倾角效应，当解理倾角由0°增加到90°时，岩石的弹性模量、单轴压缩强度及峰后脆延特征都会发生变化，穿晶总裂纹数受影响明显，主要体现在钾长石张拉穿晶裂纹显著增加，钾长石剪切裂纹数量在60°增加到最大值后减少，石英穿晶张拉裂纹数量也有明显变化，总体而言不断增加，而沿晶裂纹数量呈减少趋势，整个开裂过程仍以张拉沿晶主导；（2）晶粒解理倾角效应受围压影响，围压会导致沿晶裂纹和穿晶裂纹数量和二者比值发生变化，但不同倾角下围压对沿晶裂纹和穿晶裂纹数量和比值变化影响不一样；（3）当解理间距由2 mm增加到4 mm时，穿晶裂纹数量有增加趋势，而沿晶裂纹数量减少，总剪切和张拉裂纹数量比值不变，对岩石微观张拉、剪切破坏机制无明显影响。此外，具有解理结构的矿物晶粒含量较高且矿物晶粒本身性质对岩石性质及响应影响显著时，解理特征对板裂、岩爆等破坏的影响应给予重视。 

Effect of cleavage characteristics of mineral grains on the failure process of hard rock based on UDEC-GBM modeling

Based on the UDEC (Universal distinct element code) modeling and grain-based model (UDEC-GBM), the effects of mineral’s (e.g., feldspar) cleavage angle, the confining effect of the cleavage angle and cleavage spacing on mechanical properties, microcracking process and mechanism of hard rocks, and the resulting problems in engineering were investigated in the present study. Numerical results show that: (1) Mineral cleavage has a considerable angle effect. As the cleavage angle increases from 0° to 90°, the elastic modulus, uniaxial compressive strength, and post-peak characteristics of the rock are affected. The total number of transgranular cracks is obviously affected, which is mainly reflected by the increase in the number of feldspar tensile cracks and the number of feldspar shear cracks increases to a maximum at 60° and then decreases, and the number of quartz tensile cracks changes considerably. In general, the number of transgranular cracks increases, while the number of intergranular cracks decreases. However, tensile and intergranular cracking dominate the cracking process. (2) The cleavage effect is affected by the confining pressure. The confining pressure will cause the number and proportion of intergranular cracks and transgranular cracks to change. However, the confining pressure at different angles has different effects on the number and proportion of intergranular cracks and transgranular cracks. (3) As the cleavage spacing increases from 2 to 4 mm, the number of transgranular cracks increases and the number of intergranular cracks decreases. However, the ratio of the total shear and tensile cracks remains constant, indicating that microscopic tensile and shear cracking mechanisms are almost unaffected. In addition, when the proportion of minerals with cleavage characteristics is high and the type of mineral has a considerable influence on the rock properties, the influence of cleavage characteristics on rock failures, such as spalling and rockburst, should be given attention.