爆破荷载作用下岩体损伤破坏的分形研究

Fractal study of rock damage under blasting loading

通过对现有损伤参量的定义方法的分析,尝试采用分形维数作为表征岩石损伤的参量,建立分形维数与损伤程度的相对关系。根据盒维数算法思想及数字图像存储原理,编写了基于Matlab的数字图像的简易盒维数算法。结合实际工程爆破施工,采用数字式全景钻孔摄像系统进行了现场测试。通过对实测的爆前、爆后岩体的影像资料进行裂纹提取及图形处理,得到了爆破前后岩体损伤裂纹对应的分形维数,确定了爆破作用下所产生的损伤增量。结果表明,用分形维数来描述岩石的损伤,克服了其他定义方法涉及过多岩石特性参数的不便,其结果为研究岩石的损伤程度及演化过程,探索了一条新的途径。

Through analyzing the existing definitions of damage variables,we try to use the fractal dimension as a characteristic of the rock damage variable and establish the relationship between fractal dimension and damage degree.According to the calculation method of box-counting dimension and digital image storage principles,to compile the simple digital image of a box-counting dimension algorithm based on Matlab.Combining with practical project of blasting,the digital panoramic borehole camera system is taken for field-test.Through extracting the crack from images of the before explosion and post-explosion of blasts rock,then some graphics processings are made to get the fractal dimensions corresponding to cracks.Finally,damage increments under the action of blasting are determined.The results show that the using fractal dimension to describe the damage of rock,overcomes the disadvantages of other definition methods which involve too much rock characteristic parameters,so as to explore a new way to study the damage degree and evolution process of rock damage.