大比尺切削模型试验条件下砂岩破坏特征研究

为探究单刀齿线性切削作用下岩石的破坏规律,利用大比尺模型试验平台对砂岩开展了线性切削试验,结合分形几何学方法,对砂岩在不同切削角度及不同切削深度下的切削产物,包括切削沟槽的尺寸及切削碎块的几何特征进行了分析。试验结果表明,切削影响宽度与切削深度呈良好的线性关系,且随切削深度的增加而增加,切削角度为45°时相同切削深度对应的切削影响宽度最小。砂岩的切削碎块块度分布具有分形特征,分形维数集中在1.88～2.66。分形维数与切削深度呈良好的线性关系,随切削深度的增加而减小。分形维数与切削角度间的关系可统一用二次函数进行拟合,但随着切削深度的增加,函数二次项系数由正值变为负值。

Sandstone failure characteristics in large-scale cutting model tests

In order to explore the failure mechanism of rocks under linear cutting with single cutter,a large-scale model test platform was used to carry out linear cutting tests on sandstone.This study employed the fractal geometry method to analyze the geometric characteristics of cutting products,including cutting grooves and cutting fragments,at different cutting angles and different cutting depths.The experimental results show that the cutting width has a good linear relationship with the cutting depth,and increases with the increase of the cutting depth.The cutting width corresponding to the same cutting depth is the smallest when the cutting angle is 45 degrees.The fragment-size distribution of sandstone has fractal characteristics and the fractal dimension is concentrated in the range of 1.88-2.66.The fractal dimension has a good linear relationship with cutting depth and decreases with the increase of cutting depth.The relationship between fractal dimension and cutting angle can be fitted by quadratic function,but the coefficient of quadratic term of the fitted function changes from positive value to negative value with the increase of cutting depth.