粉砂岩破裂过程中波速场演化特征试验研究

Experimental study on the characteristics of wave velocity field evolution in siltstone fracture process

为探究载荷作用下波速场演化特征,进行了粉砂岩分级加载试验,以波速成像云图为研究对象,对岩石破裂过程中波速场的阶段性、区域性演化特征展开研究。结果表明:应用波速成像技术对岩石的探伤效果良好,其中,低波速带与裂纹位置相吻合,高波速带与完整基岩区域一致;岩石在破裂过程中,伴随着裂纹发育,波速场的平均波速值与结构相似性均持续降低,损伤程度的差异越来越大;基于K-means法将岩石区域划分为3类,即完整域Ⅰ、弱化域Ⅱ与损伤域Ⅲ;区域的演化特征体现了岩石的非均质性特性,并通过熵权法判定3类区域对岩石损伤程度的影响性排序为损伤域Ⅲ>完整域Ⅰ>弱化域Ⅱ。

In order to study the evolution characteristics of wave velocity field,the siltstone step loading experiment was carried out.The phase and regional evolution characteristics of wave velocity field during rock fracture were studied.The results showed that the wave velocity imaging technology had a good effect on rock flaw detection,the low wave velocity zone coincided with the crack location,and the high wave velocity zone coincided with the complete bedrock area.Along with the development of cracks,the average wave velocity value and structural similarity of wave velocity field continued to decrease,and the difference of damage degree increased.Based on K-means method,rock regions were divided into three classes:lossless domainⅠ,weak domainⅡand damage domainⅢ.The evolution characteristics of region reflected the heterogeneity of rock.Computation by entropy weight method,the influence of three types of zones on rock damage degree was:damage domainⅢ>lossless domainⅠ>weak domainⅡ.