为研究切削前角对刀齿切削岩石的影响，利用自主研发的刀齿线性切削岩石试验装置对砂岩进行切削前角处于-40°~50° 区间的切削试验.实时采集试验中刀/岩的相互作用力，记录所形成的切削槽形状，收集切削形成的岩石碎块并得到其粒径分布，进而分析岩石碎块的分形特征；同时，利用碎块的分形维数定量描述碎块的粒径分布.结果表明：随着切削前角从 -40° 逐渐增加到50°，切削槽的宽度不断增大，尤其是在切削槽初始形成端；随着切削前角的增加，岩石碎块的分形维数、刀/岩的平均切向力和平均法向力均逐渐减小，且其均可采用切削前角的指数函数表示，平均切削力与平均法向力的比值处于0.56~1.84之间，且无规律性变化.
In order to investigate the effects of rake angle on rock cutting, a linear rock cutting device was invented and used to conduct rock cutting experiments with chisel picks on sandstone with rake angle ranging from -40° to 50°. The interaction forces between picks and rocks were real-time recorded. The grooves created in the experiments were captured. The pieces of debris were collected and the size distribution was obtained. The fractal features of the debris pieces were analyzed. And the debris pieces’ size distribution was quantitatively described by their fractal dimension. The results show that with the increasing of rake angle from -40° to 50°, the width of the groove increases, especially in the initial part of the groove. The fractal dimension of the debris and the cutting force on the picks decrease gradually with the increasing of the rake angle. They can be expressed by the exponential function of the rake angle. However, the ratio of mean cutting force to mean normal force remains between 0.56 and 1.84, and seems not be affected by the rake angle.
［1］王成勇, 刘培德, 胡荣生. 花岗岩切削破碎过程研究［J］. 岩石力学与工程学报, 1991, 10(2): 185-196.
WANG Chengyong, LIU Peide, HU Rongsheng. Study of granite cutting process［J］. Chinese Journal of Rock Mechanics and Engineering, 1991, 10(2): 185-196.
［2］LIU S Y, DU C L, CUI X X. Research on the cutting force of a pick［J］. Mining Science and Technology, 2009, 19(4): 514-517.
［3］LIU S Y, DU C L, CUI X X, et al. Characteristics of different rocks cut by helical cutting mechanism［J］. Journal of Central South University of Technology, 2011, 18(5): 1518-1524.
［4］ACHANTI V B, KHAIR A W, SOC M. Bit geometry effects on failure characteristics of rock［J］. Mining Engineering, 2000, 52(6): 101-107.
［5］COPUR H, BILGIN N, TUNCDEMIR H, et al. A set of indices based on indentation tests for assessment of rock cutting performance and rock properties［J］. Journal of the South African Institute of Mining and Metallurgy, 2003, 103(9): 589-599.
［6］KIM E, ROSTAMI J, SWOPE C, et al. Full scale linear cutting experiment to examine conical bit rotation［J］. Journal of Mining Science, 2012, 48(5): 882-895.
［7］BILGIN N, DEMIRCIN M A, COPUR H, et al. Dominant rock properties affecting the performance of conical picks and the comparison of some experimental and theoretical results［J］. International Journal of Rock Mechanics and Mining Sciences, 2006, 43(1): 139-156.
［8］BALCI C, Bilgin N, PERGAMON E S. Correlative study of linear small and full-scale rock cutting tests to select mechanized excavation machines［J］. International Journal of Rock Mechanics and Mining Sciences, 2007, 44(3): 468-476.
［9］COPUR H, PERGAMON E S. Linear stone cutting tests with chisel tools for identification of cutting principles and predicting performance of chain saw machines［J］. International Journal of Rock Mechanics and Mining Sciences, 2010, 47(1): 104-120.
［10］EVANS I. A thoery on the basic mechanics of coal ploughing［C］//Proceedings of a Symposium Held at the University. London: University of Missouri, 1962: 761-798.
［11］NISHIMATSU Y. The mechanics of rock cutting［J］. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1972, 9(2): 261-270.
［12］欧阳义平, 杨启. SPH法数值仿真三维切削破岩和切削力估算［J］. 上海交通大学学报, 2016, 50(1): 84-90.
OUYANG Yiping, YANG Qi. Numerical simulation of rock cutting in 3D with SPH method and estimation of cutting force［J］. Journal of Shanghai Jiao Tong University, 2016, 50(1): 84-90.
［13］欧阳义平, 杨启, 马健, 等. 刀齿线性切削岩石试验装置: CN103499505A ［P］. 2014-01-08［2017-03-17］.
OUYANG Yiping, YANG Qi, MA Jian, et al. Experimental device for linear rock cutting with picks: CN103499505A ［P］. 2014-01-08［2017-03-17］.
［14］JIANG H X, DU C L, LIU S Y, et al. Fractal characteristic of rock cutting load time series［J］. Discrete Dynamics in Nature and Society, 2014, 2014(1): 1-8.
