基于裂纹的截齿破岩力学性能研究

Study on Mechanical Properties of Rock Fragmentation by Cutting Tooth Based on Crack

采用颗粒流PFC2D软件建立镐形截齿截割岩石的离散元模型,通过改变截割角度和截割深度,对岩石颗粒裂纹、截齿载荷以及截齿的综合截割性能进行分析。结果表明:截割角度越大,对岩石的剪切作用越明显,产生裂纹的数目越多,但岩石深处颗粒接触失效较少,不利于裂纹的扩展;随着截割深度的增加,岩石参与截割的部分增大,产生裂纹的数目增多;随着截割角度的减小和截割深度的增加,截割切向力和法向力均增大;截割角度为52°,截割深度为3 mm时,截齿的综合截割性能最佳。讨论仿真模型参数,如颗粒间摩擦因数和颗粒的弹性模量对仿真结果的影响。结果表明:随着摩擦因数和弹性模量的增大,得到的截割力也随之增大,其中摩擦因数和弹性模量对截割力的影响分别为0.48和0.37。研究结果为截齿和采掘机械截割系统的设计以及截割工艺的优化提供了参考。

PFC2 D software was used to establish the discrete element model of the pick to cut rock.By changing the cutting angle and cutting depth, the rock particle cracks, the load of the pick and the comprehensive cutting performance of the pick were analyzed.The results show that the larger the cutting angle, the more obvious the shearing effect on the rock, and the more cracks are generated.But the contact failure of particles in the depth of the rock is less, which is not conducive to the expansion of cracks.With the increase of cutting depth, the portion of rock involved in cutting increases and the number of cracks increases.As the cutting angle decreases and the cutting depth increases, both the tangential force and normal force are increased.When the cutting angle is 52° and the cutting depth is 3 mm, the overall cutting performance of the pick is the best.The effects of simulation model parameters, such as the friction coefficient between particles and the elastic modulus of the particles, on the simulation results were discussed.The results show that with the increase of friction coefficient and elastic modulus, the obtained cutting force also increases, and the effects of the friction coefficient and elastic modulus on the cutting force are 0.48 and 0.37,respectively.The research results provide a reference for the design of the cutting tool and the mining machinery cutting system and the optimization of the cutting process.