微波照射下影响花岗岩损伤因素敏感性研究

发布时间：2018-03-10 18:58

本文选题：微波照射　切入点：花岗岩　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：在现今的破岩工作中,大多采用微波辅助机械破岩的方法,首先对岩石进行微波照射以降低强度,进而采用机械破碎。为更大程度的降低岩样强度,提高破岩的工作效率,需对微波照射参数、冷却方式、照射及冷却后岩石内部变化及矿物成分等因素进行研究。本文将采用试验研究的方法,以陕西秦岭和河北平山县花岗岩为主要研究对象,对在微波照射条件下,影响花岗岩损伤的上述因素进行研究,主要研究内容及结论如下:(1)从理论方面阐述了微波的加热原理及岩石的损伤劣化机制,得出微波照射对岩石造成损伤的主要原因,即岩石内部不同矿物具有不同微波吸收率和热膨胀系数。在微波照射作用下,岩石中的吸波矿物迅速升温形成“热点”,与周围矿物形成温度差,进而产生热应力,当热应力大于岩石抗拉强度即造成岩石损伤。(2)首先采用三组不同的微波照射参数对花岗岩进行照射,随后进行四种不同冷却方式的冷却试验,最后对岩样进行抗压强度试验,得到如下结论:在某一功率及时间,试样内很多矿物发生熔融和相变,如锡石和石英,矿物的熔融导致岩样内部体积迅速增大,并伴随熔融物质的溢出,经对比和推断,黑色物质为锡石;四种冷却方式能够不同程度降低岩石试件强度,降低程度从大到小依次为水流冲击冷却、浸泡冷却、喷水冷却、自然冷却。(3)采用FLIRT420热成像仪对照射及冷却后的岩样进行温度检测,分别进行点、线、面三方面的温度测量,得到如下结论;仅对于本次所有岩样,内部含有锡石矿物的,岩样温度能快速升高且能升高达到的温度远高于其它,宏观表现为岩样表面出现裂纹,条数并增多。
[Abstract]:In today's rock breaking work, microwave assisted mechanical rock breaking method is mostly used. Firstly, microwave irradiation is carried out to reduce the strength of rock, and then mechanical crushing is adopted to reduce the strength of rock sample to a greater extent and improve the working efficiency of rock breaking. It is necessary to study the parameters of microwave irradiation, the cooling mode, the variation of rock interior and mineral composition after irradiation and cooling. In this paper, the main research objects are Qinling granite in Shaanxi Province and Pingshan County in Hebei Province. The above factors affecting the damage of granite under microwave irradiation are studied. The main contents and conclusions are as follows: (1) the principle of microwave heating and the mechanism of damage deterioration of rock are expounded theoretically. The main causes of rock damage caused by microwave irradiation are obtained, that is, different minerals in rock have different microwave absorptivity and thermal expansion coefficient. The wave-absorbing minerals in the rocks rise rapidly to form a "hot spot", which forms a temperature difference with the surrounding minerals, and then produces thermal stress. When the thermal stress is greater than the tensile strength of rock, the damage of rock is caused by three groups of different microwave irradiation parameters, then four cooling tests of different cooling methods are carried out, and finally, the compressive strength of rock samples is tested. The conclusions are as follows: at a certain power and time, many minerals in the sample undergo melting and phase transition, such as cassiterite and quartz. The melting of minerals leads to the rapid increase of the internal volume of the rock sample, and accompanied by the overflow of the molten substance. The black substance is cassiterite, and the four cooling methods can reduce the strength of rock specimen in varying degrees, and the degree of decrease from large to small is water impact cooling, immersion cooling, spray cooling, Natural cooling. 3) the temperature of irradiated and cooled rock samples is measured by FLIRT420 thermal imager, and the temperature measurement of points, lines and surfaces is carried out respectively, and the following conclusions are obtained: for all rock samples, only for this time, there are cassiterite minerals in the inside. The temperature of rock sample can rise rapidly and the temperature that can rise is much higher than that of other samples. The macroscopic manifestation is that cracks appear on the surface of rock sample and the number of strips increases.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU45

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