岩石力学特性与破碎产品粒度之间的关系和规律

发布时间：2018-04-02 16:00

本文选题：岩石　切入点：不规则　出处：《内蒙古科技大学》2014年硕士论文

【摘要】：岩石破碎是一个复杂的过程，各个学者的研究推动了岩石在破碎方面的发展岩石破碎时的力学状况主要是用弹性力学的方法进行分析的，但是，岩石在受力破碎时的分析是很困难的，由于岩石内部存在各种各样的裂纹弱面等，岩石材料的各种常数的离散度较大，经计算后，得到的结果会有很大的偏离分析岩石破碎前的应力分布情况，对岩石破碎后情况做出一些判断选取不规则的岩块进行点荷载实验得到其强度，通过破碎机对所选岩块进行破碎，筛分后得到其粒度分布情况，探讨岩块的力学特性与其破碎粒度间的关系使用数值模拟软件ANSYS，探讨岩石的破坏机理通过LY-DYNA三维数值模拟分析，岩块在刚体冲击过程中的应力在岩块中的传播过程，所模拟的岩块在冲击中的破碎情况，从而探讨岩石的力学特性与破碎产品粒度间的关系和规律如下所示： 1）符合随着岩块尺寸的下降，强度随之上升这一规律；由于岩块尺寸的下降，岩石内部的缺陷是越难扩展，故岩石的强度上升； 2）不规则岩块的强度有很强的尺寸效应，受岩块尺寸的影响很大；点荷载测得岩块强度尺寸小时强度值偏大，随着岩块的尺寸增加，岩块的强度离散性逐渐减小岩块尺寸较大时，不规则形状系数大，表面凸凹较大，破坏时容易产生应力集中，故其破坏强度较低岩块尺寸的减小，容易产生应力集中的部分减少，，故其强度增大 3）不同重量的矿块在破碎后，其粒度分布是相似的，在某一均值波动；岩块破碎后，其粒度是大大小小分布的，其中间某种粒度的范围比较多岩块粒度分布越不均匀时，岩块强度就越小；反之，岩块粒度分布均匀时，岩块强度就越大 4）刚体冲击岩石过程中，岩石的应力变化过程为先增大后减小的循环过程，岩石破碎的过程表现为先压实，后压裂的循环过程刚体的冲击速度越大，刚体侵入岩石的深度会更深，从而岩石的破坏会更剧烈
[Abstract]:Rock breakage is a complex process. The research of various scholars has promoted the development of rock fragmentation. The mechanical condition of rock breakage is mainly analyzed by means of elastic mechanics, but,It is very difficult to analyze the rock when it is broken by force. Because of the existence of various cracks and weak surfaces inside the rock, the dispersion of various constants of the rock material is large, after calculation,The results obtained will deviate greatly from the analysis of stress distribution before rock breakage, and make some judgments on the situation after rock breakage.The strength of irregular rock block is obtained by point load experiment. The selected rock block is broken by crusher, and the particle size distribution is obtained after sifting.The relationship between the mechanical properties of the rock and the particle size of the broken product is discussed as follows:1) accord with the law that the strength increases with the decrease of the rock size, because of the decrease of the rock size, it is more difficult to expand the defects inside the rock, so the strength of the rock increases;2) the strength of irregular rock block has a strong size effect, which is greatly affected by the size of rock block.When the strength dispersion of rock block decreases gradually, when the size of rock block is larger, the irregular shape coefficient is large, the surface convex and concave is larger, and the stress concentration is easy to occur during failure, so the size of rock block with lower failure strength decreases.It is easy to reduce the part of stress concentration, so its strength increases.The smaller the strength of rock block is, the greater the strength of rock block is when the particle size distribution of rock block is uniform.4) in the process of rigid body impacting rock, the stress change process of rock is a cycle process of increasing first and then decreasing, the process of rock breaking is compaction first, and the impact velocity of rigid body increases in the process of fracturing.The rigid body invades the rock deeper, and the destruction of the rock becomes more severe.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45

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