BROKEN CHARACTERS OF ROCK UNDER DIFFERENT CYLINDRICAL LOADS
岩石试件在不同圆柱荷载作用下的破坏特征

When cutting, drilling and fragmenting rock, failure mechanism around cylindrical load is an important research subject to improve cutting efficiency. Through diametrical compressive test on rock samples under cylindrical loads with different diameters, the broken process of rock is analyzed. With the load increment, the invading depth of head also increases. When the load decreases abruptly, however, the invading depth increases suddenly. Experimental data reveal a linear relation between leaping load and cylindrical cutting area. With the cutting diameter reducing, the leaping broken character of rock becomes more and more obscure; and the second formation process of fracture will not appear. At the same time, the final broken load reduces gradually; and the block after fragment is homogeneous and complete. Meanwhile, the stress distribution of press model is discussed. Analytical result indicates that the stresses at the place far from the loaded point approach consistent, which is complete in accordance .with the experimental result.