含缺陷砂岩裂纹扩展特征试验与模拟研究

Experimental and Numerial Investigation on Crack Expansion of Sandstone Containing Flaws

采用岩石力学伺服控制试验机和声发射仪,对含缺陷砂岩进行了单轴压缩试验,研究了岩石的裂纹扩展和声发射特征。同时采用岩石破裂过程分析系统进行了模拟研究,试验结果和模拟结果具有较好的一致性。在此基础上进行了多次重复模拟试验,探讨了材料非均质性对岩石裂纹扩展特征的影响。实验结果表明:岩石材料裂纹扩展特征与材料非均质性密切相关,主裂纹首先在裂隙尖端产生并沿垂直裂隙方向扩展,而后改沿最大主应力方向朝端部扩展,但此后的裂纹扩展方向不同,且主裂纹在各阶段扩展长度、速度不同;同时,次生裂纹参数(数量、长度、宽度、走向)存在差异。

In this paper, to research the crack propagation and AE behavior of rock mass, an uniaxial compression text was conducted on the sandstone samples by using the servo-controlled testing machine and AE monitoring system. Meanwhile, a numerical simulation was carried out with the rock failure process analysis system, while the numerial results displayed a good consistency with the experimental results. On this basis, the influences of material heterogeneity on crack propagation were further studied by using multiple repeated simulation. The results show that the crack propagation of sandstone is greatly related to the heterogeneity of rock material. The main crack of the sandstone sample initiates from the end of pre-exiting crack firstly, and expands along the perpendicular of pre-exiting crack. Then the development of crack turned towards the loading direction, whereas, lately, the cracks on the sam- ples grow in different directions whilst the length and speed of crack propagation are various at different stages. Moreover, the secondary crack parameters including secondary crack number, length, width and expanding direction are different.