【作者】 李涛；

【导师】 戴俊；

【作者基本信息】 西安科技大学 ， 岩土工程， 2019， 硕士

【摘要】 随着我国综合实力的不断提高,岩土工程和采矿工程中岩石破碎技术的研究意义越发重要。目前关于微波参数对岩石的影响研究较多,而对于岩石的劣化与微波循环照射方式,岩石中水分,热湿循环的关系却研究不足。进行微波照射条件下热湿作用岩石强度劣化试验研究对推广微波作为辅助破岩技术具有十分重要的理论意义和现实价值。本文主要借助微波发生装置和万能试验机对花岗岩试件进行微波照射和常规静态力学试验,探讨在不同功率微波、循环次数、循环方式下花岗岩的强度劣化规律。同时辅以XRD、SEM和FLIR热成像仪,对岩样的组成成分进行分析,观察微波照射前后试样的内部裂纹形态和微波照射后试样的温度变化规律,主要研究内容和结论如下:(1)结合岩石中不同矿物成分在微波照射下的升温特性及岩石中水分如何发挥作用,分析微波作用下岩石内部产生破裂的原理及水分对岩石的作用机理。得出结论:岩石的矿物成分、微波参数和岩石中水分会影响花岗岩经微波作用后的强度。(2)采用900W低功率微波对花岗岩试样分别进行热湿循环或热循环处理,单次微波照射时间均为2min,然后对试样进行巴西劈裂抗拉力学性质试验。使用2kW、4kW和6kW功率微波对花岗岩试件进行热湿循环或热循环处理,单次微波照射时间均为2min,随后测量微波照射后无围压时花岗岩试样的抗压强度。得出结论:花岗岩强度在同一功率下随循环次数增大逐渐减小。在相同循环次数下花岗岩强度随着微波功率的增大而降低,在相同微波功率和循环次数下热湿循环对岩石强度的劣化效果更佳。(3)分别对经2kW、4kW和6kW功率微波4次热湿循环和热循环照射的花岗岩试件和对照组试件等进行XRD和SEM电镜试验,借助FIIR热成像仪对高功率微波作用的试样进行温度变化规律分析。得出结论:花岗岩矿物成分主要有石英、角闪石和黑云母。微波照射后花岗岩内部产生大量沿晶断裂型和穿晶断裂型微观裂纹。微波照射后试件的最高温度和平均温度与微波功率、循环次数和循环方式有关。更多还原

【Abstract】 With the continuous improvement of China’s comprehensive strength,the research significance of rock crashing technology in geotechnical engineering and mining mengineering is more and more important.At present,there are many researches on the influence of microwave parameters on rocks,but the relationship between the deterioration of rocks and the way of microvwave circulatior0,the relatiolrnship between moisture and heat and humidity in rocks is not enough.The experimental study on the strength degradation of hot and hemid rock under microwave irradiation has certain theoretical and practical value for popularizing microwave as auxiliary rock breaking technology.In this paper,microwave irrradiation and conventional static mechanical tests are carriecd out on granite specimens by means of microwave generating cdevice and universal testing machine.The strerngth deterioration law of granite under different power micarowaves,cycle times and circulation modes is discussed.At the same time,XRC,SEM and FLIR thermal imager were used to analyze the composition of the rock sample.The internal crack morphology of the sample before and after microwave irradiation and the temperature change of the sample after microwave irradiation were observed.The main research contents and conclusions are follows:(1)Combining the temperature rise characteristics of different mineral components in the rock under microwave irradiation and how the water in the rock plays a role,analyze the principle of cracking inside the rock under microwave action and the action mechanism of water on rock.It is concluded that the mineral composition of the rock,the microwave parameters and the moisture in the rock affect the strength of the granite after microwave action.(2)The granite samples were subjected to hot-wet circulation or thermal cycle treatment with 900W low-power microwave.The single microwrave irradiation time was 2min,and then the specimen was subjected to Brazilian splitting tensile mechanical properties test.The granite specimens were subjected to hot-wet circulation or thermal cycle treatment using 2kW,4kW and 6kW power microwaves.The single microwave irradiation time was 2min,and then the compressive strength of the granite samples after microwave irradiation without confining pressure was measured.It is concluded that the granite strength decreases with the increase of the number of cycles at the same power.The granite strength decreases with the increase of microwave power under the same number of cycles.The heat and humidity cycle has better effect on rock strength degradation under the same microwave power and cycle number.(3)XRD and SEM electron microscopy tests were carried out on granite specimens and control specimens irradiated by 2 kW,4 kW,6 kW power microwaves,4 times of heat and humidity cycles and heat cycles,and the high power microwave was applied by means of FIIR thermal imager.The sample was analyzed for temperature variation.It is concluded that the mineral components of granite are mainly quartz,amphibole and biotite.After microwave irradiation,a large number of intergranular fracture and trans granular fracture microscopic cracks were generated inside the granite.The maximum temperature and average temperature of the test piece after microwave irradiation are related to the microwave power,the number of cycles and the cycle mode.更多还原