滚刀线性侵入试验中岩石破裂模式研究

Linear cutting experiments on crack modes of rock under indentation of a single disc cutter

采用北京工业大学自主研制的大型机械破岩试验平台,研究了北山花岗岩在单个滚刀单次及多次线性侵入试验中的岩石破裂情况。试验采用直径17英寸(432 mm)的常截面盘形滚刀,对尺寸1000 mm×1000 mm×600 mm的花岗岩试样进行了侵入试验。研究发现在滚刀切槽周边,随距离远近,岩石破裂程度不一。基于试验观察和裂纹数字化处理结果,将岩样分划为岩粉区、破裂区和原岩区3个区域,并对各区的尺寸和面积加以统计。同时对波速和回弹指标进行测试,发现各区内的指标存在明显差异。随着侵入次数增多,岩石中破裂各区的面积有明显增大,但相应区域内的指标变化并不显著。

In order to study the crack modes of Beishan granite under the indentation of a single disc rolling cutter, a series of linear cutting experiments are conducted on the Mechanical Rock Fragmentation Experimental Platform developed by Beijing University of Technology. During the experiment, a constant cross-section disc cutter with a diameter of 17 inches (432 mm) is used and a block of Beishan granite with the size of 1000×1000×600 mm is adopted. After the tests, it is found that there is a cracked part beneath the groove with varied fragmentation degree. Based on the observed crack mode and crack density, the rock sample is classified into re-compacted zone, crushed and cracked zone and intact rock zone, then the sizes and areas of these zones are summarized accordingly. Meanwhile the ultrasonic velocity tests and rebound tests are conducted to obtain the properties of different zones. Finally, it is found that these test results agree well with the fragmentation degrees of different zones. In addition, as the time of cutting increases, the areas of these zones expand significantly, while the properties of the corresponding zones almost keep constant.