高地应力硬岩冲击动态力学性能研究

发布时间：2018-03-12 13:38

本文选题：SHPB试验　切入点：动态力学性能　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：矿产资源地下开采是一个自上而下的过程,开采过程中采掘工作面随资源赋存状况逐步下降,开采深度逐渐增加,当深度达到一定程度矿井进入深部开采。深部岩体开挖前已处于较高的应力场中,高地应力不仅容易导致深部巷道变形加剧、矿柱失稳、岩爆现象频发等,而且岩石在有高应力作用时力学性质发生改变,与浅部岩体有较大差别。爆破在硬岩开采过程中起着尤为重要的破岩作用,采矿过程中炸药爆炸对周围岩石造成的应变率在101s-1～103s-之间,研究高应变率作用及高应力高应变率共同作用下岩石表现的动态力学性质,对安全高效的开采深部矿体有重要意义。玉溪矿业有限公司狮子山矿现已开拓至十八中段,未来生产与开拓的主要中段已达到深部开采范畴,本文围绕课题《狮子山矿深部采矿工艺的研究和应用》的子课题《深部矿石、岩石冲击动态力学性能的试验研究》展开。在阅读大量文献的基础上进行理论分析、现场采样、室内试验,对狮子山矿深部矿岩的动态力学性能进行了较为系统的研究。主要内容和结论性成果如下:(1)SHPB冲击试验中矿岩表现出很强的脆性,冲击对试件造成的应变、应变率、平均应变率变化范围都比较小,而动态强度、动弹性模量较高。即使以很高的动荷载加载,仍然没有获得较大的应变率。试验中对绝大部分试件造成的应变在0.008以内,平均应变率在70s-1以内,最大动弹性模量则超过了 140GPa。(2)现场取样的白云岩均质性较差,但试件动态强度与平均应变率之间整体上表现出较强的正相关性;一维动静组合与三维(12MPa围压)动静组合试验中,试件动态强度(相同或相近应变率时)先随轴压增加增大,而后出现了减小的趋势,在24MPa轴压附近动态强度达到最大值。围压作用对试件的力学性能有影响,试验中轴压固定在24MPa,围压在4MPa时试件强度与无围压状态的差别不明显,但8MPa和12MPa围压作用时动态强度增强较大。(3)—定范围内的轴压、围压作用使试件储存了应变能,增强了其抗冲击性能,不利于试件对冲击能量的吸收,试件虽然破坏整体却可能表现出释放能量,大量能量以其他形式散失。但随着冲击荷载的不断增大,用于破碎试件的部分冲击能逐渐大于其自身释放出的能量,岩石整体逐渐向吸能趋势转变。
[Abstract]:Underground mining of mineral resources is a top-down process. In the process of mining, the mining face decreases gradually with the occurrence of resources, and the mining depth increases gradually. When the depth of the mine reaches a certain level, the deep rock mass is already in a high stress field before excavation. The high ground stress not only causes the deformation of the deep roadway to intensify, the pillar is unstable, and the phenomenon of rock burst occurs frequently, etc. In addition, the mechanical properties of rock are changed under the action of high stress, which is different from that of shallow rock mass, and blasting plays a particularly important role in breaking rock in the process of hard rock mining. In the mining process, the strain rate caused by explosive explosion on the surrounding rock is between 101s and 103s-. The dynamic mechanical properties of the rock under the combined action of high strain rate and high stress and strain rate are studied. It is of great significance for safe and efficient mining of deep orebodies. Shizishan Mine of Yuxi Mining Co., Ltd. has been developed to the middle of 18, and the main middle section of future production and development has reached the scope of deep mining. This paper focuses on the research and application of deep mining technology in Shizishan Mine, which is a sub-subject < Deep Ore, Experimental study on dynamic Mechanical Properties of Rock impact,'. Based on reading a large number of literatures, theoretical analysis and field sampling are carried out. In laboratory tests, the dynamic mechanical properties of deep ore rocks in Shizishan Mine have been systematically studied. The main contents and conclusions are as follows: in the impact test of the rock, the rock shows strong brittleness, and the strain and strain rate caused by the impact on the specimen. The range of average strain rate is relatively small, but the dynamic strength and dynamic elastic modulus are higher. Even if loaded with very high dynamic load, no large strain rate has been obtained. The strain caused by the test for most of the specimens is less than 0.008. The average strain rate is less than 70 s ~ (-1), and the maximum dynamic elastic modulus is more than 140 GPA. 2) the dolomite sampled in the field is poor in homogeneity, but the dynamic strength of the specimen and the average strain rate are positively correlated as a whole. The dynamic strength of the specimen (at the same or similar strain rate) firstly increases with axial compression and then decreases, in the dynamic and dynamic combination test of one-dimensional dynamic and dynamic combination and three-dimensional 12MPa confining pressure, and the dynamic strength of the specimen increases with the axial compression at the same or similar strain rate. The dynamic strength near the axial pressure of 24MPa reaches the maximum. The confining pressure has an effect on the mechanical properties of the specimen. In the test, the strength of the specimen is fixed at 24MPa, and the difference between the strength of the specimen and that of the specimen without confining pressure is not obvious when the confining pressure is at 4MPa. However, under the confining pressure of 8MPa and 12MPa, the dynamic strength increases greatly in the range of axial compression. The confining pressure causes the specimen to store the strain energy and enhance its impact resistance, which is not conducive to the absorption of the impact energy of the specimen. Although the whole specimen may have released energy, a large amount of energy may be lost in other forms. However, with the increasing of impact load, the partial impact energy used to break the specimen is gradually larger than the energy released by itself. The whole rock gradually changes to the trend of energy absorption.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD324

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