岩石冲击切削破碎声电效应与能量演化规律研究

The mechanism of acoustic emission (AE) and electromagnetic emission (EME) produced in the process of rock impusing cutting breakage will be analyzed theoratically; the influence of the loading way, loading parameters, and loading frequency on AE and EME will be discussed; the characteristic parameters coupling relationship between stress field and the field of AE and EME will be studied. A three-dimensional model to describe the evolution of crack extention during rock breakage will be investigated, which is based on the study of the temporal density of energy flow, the energy transfer and dissipation law, the development and evolution of internal rock fissures, as well as the fracture energy dissipation and timeliness of rock breakage under the impact of impulsing cutting. Rock breaking tests with different mineral rocks will be performed under the self-developed multifunction rock breakage testing machine. The datum of AE, EME, dynamic loading stress wave and three-direction cutting force will be collected, and utilized for futher numerical analysis. Synchronously, a panoramic photoelastic experiment will be performed to testified the numerical analysis. By summarizing the results of experiment and theoretical analysis, the characteristics of AE and EME and energy evolution law during rock impulsing cutting breaking energy will be found out. It will provide a theoretical basis for understanding the mechanism of rock impulsing cutting breaking, exploring new breaking method, directing deep drilling scientifically, and reducing energy consumption. In the meantime, it will provide guidance for mining and disaster prevention of rock engineering.

从理论上分析岩石冲击切削破碎过程中产生声发射和电磁辐射效应的机制，探讨冲击切削加载方式、加载参数与频次及岩石属性参数对声发射和电磁辐射场的影响，建立应力场与声发射和电磁辐射场特征参量的耦合关系。研究冲击切削作用下能流时空密度、能量转化与耗能规律，岩石内部裂隙的发展与演变、裂隙耗能与岩石破碎的时效性，构建破岩过程裂隙扩展三维空间演化模型。运用自行研制的多功能岩石破碎试验机，选用不同矿岩进行各种碎岩试验，对声发射、电磁辐射、施载动态应力波及切削三向力等信息进行同步采集，并进行数值模拟分析及光弹试验验证。总结理论分析、破岩试验及数值分析成果，揭示岩石冲击切削破碎声发射和电磁辐射特征与能量演化规律，为进一步认识冲击切削破岩机理、探索新的破碎方法、科学指导深部钻探、降低能耗提供理论依据。同时，也为矿山开采、岩石工程灾害防治提供指导作用。

基于岩石破裂过程中产生声发射和电磁辐射信号，对岩石冲击与静力破碎声发射和电磁辐射信号特征与能量演化规律展开了同步研究。从理论上分析了声发射和电磁辐射能量、强度、频率与冲击/静压加载方式、载荷大小、加载速率、岩石属性参数之间的关系，建立了声发射和电磁辐射特征量与应力场之间的关系式，得到了冲击与静力刀具破岩声发射和电磁辐射参数与岩石微裂纹萌生、扩展至断裂破坏的变化规律。利用SHPB装置、RMT-150C系统、AEwin-USB型声发射信号采集系统、KBD5电磁辐射信号采集系统，选用不同矿岩、刀具进行冲击与静压破碎岩石试验，并同步采集声发射、电磁辐射、动态应力变化，与此同时开展数值模拟分析。结果表明：（1）岩石破碎是一个跃进式变化过程，其声发射和电磁辐射信号是阵发性的脉冲信号，呈跃进式变化，声电信号与岩石破碎本构关系具有较好的一致性。（2）岩石破碎声电信号能较好地表征岩石破碎过程裂纹扩展演化，信号存在载荷阀值，是岩石破坏失稳的前兆依据。（3）利用自行研发的高应变率作用下刀具破碎岩石的试验装置，开展了冲击与静载破岩对比试验，得到了受冲击与静载作用岩石的声发射和电磁辐射具有不同的特征。（4）提出了一种应用分形维数分析岩石破碎过程的新方法，刀具侵入岩石过程中声发射和电磁辐射参数序列呈现出分形特征，分形维数持续降低可作为岩石破坏失稳的前兆依据。（5）冲击载荷下不同刀具破岩吸收能随入射能增加而增加，十字型刀具能量利用率最高，其次为一字型、球型刀具，同时声发射累计能量也具有相同的趋势，表明刀具破岩效果具有差异性。（6）岩石破碎能量耗损演化具有显著的层理效应，选择合适的加载方向能有效地提高破岩效率；岩石比能量吸收量与应变率呈幂数关系，破坏形式由劈裂破坏向压碎破坏发展。总之，项目研究成果为更好地认识破岩机理，降低能耗，提高破岩效率，预防因岩石破碎失稳造成的灾害事故发生等方面提供了很好的理论依据。