Relationship And Rules Between Mechanical Properties Of Rock And Granularity Of Broken Product

The fracture of rock is a complex process, but many scholars’ study has promoted thedevelopment on rock broken. The mechanical condition when rock breaks is mainlyanalyzed by the method of mechanics of elasticity. However, the stress analysis in thebroken rock is very difficult because of the existing of crack and weak plane in the rock.And the dispersion of various constant about rock material is larger, so the result throughcalculation will have a great deviation. Analyze the conduction of stress distributionbefore rock breaking, and then make some judgment on the situation after rockfragmentation.Irregular rocks are chosen to do point load experiments to get their strength, firstlythe selected rock is crushing by crusher, secondly its particle size distribution is getting byscreening, and thirdly the relationship between the mechanical properties of the rock andits crushing granularity are discussed. Using numerical simulation software ANSYS, thispaper discusses the failure mechanism of the rock. The communication process of stress inthe rock when the rigid-body is shocking is analyzed by LS-DYNA threedimensional numerical simulations. The relationship and laws between mechanicalproperties of rocks and granularity of broken product are discussed through the simulationof rock breakage in the shocking. The conclusion as follows:1) Conformed to this law that the strength is increasing with the decreasing of theblock size. The defect in rock internal is more difficult to expand because of thedecreasing rock size, so the strength of the rock is increasing.2) The strength of irregular rock has a strong size effect, and it is largely influencedby the rock block size. The point load experiment shows that strength is large when thesize is small, and with the increasing of the rock blocks size, the dispersion of strength isdecreasing. When block size is large, the irregular shape coefficient is large, andconcavo-convex on surface is large too. It is easy to produce stress concentration when destroyed, so the damage strength is low. With the decreasing of the rock block size, thepart easy to produce stress concentration is decreasing, so the strength is increasing.3) The particle size distribution is similar with different weight of ore block aftercrushing; they fluctuate in a certain average value. The distribution of granularity is largeand small after crushing of the rock, and a range of one granularity between them is large.The more unevenness the block size distribution is, the smaller the rock strength is;conversely, the rock strength is large when the granularity distribution of rock is evenness.4) The stress of the rock is cycle change process increases first and then decreaseswhen rigid-body shock into rock. The rock breaking is cycle a process that compactionfirst then fracturing. The faster the rigid body’s velocity is, the deeper the rigid-bodyintrusive depth is, and the damage of the rock will be more intense.