节理岩体摩擦律的动力学机制研究

Great efforts had been made in the investigation of frictional constitutive relationships of rockmass, which is one of the hot issues in the study of seismogenic and earthquake sliding. However, previous works focused on the investigation of sliding friction of rockmass. This project attempts to bulid a new experimental technique to measure the physical and mechanical properties, i.e.acoustic emission and heat production, of the whole process of dynamic friction for jointed rock mass.That is, based on the large diameter Hopkinson pressure bar (SHPB) device, we will develope a multi-point acoustic emission and multi-point infrared temperature measurement system. It can be used to explore the evolution of acoustic frequencies and thermal raidation of the whole process, which involves in such three stages as the wave-induced frictional stage,the inertial frictional stage and the sliding frictional stage, of dynamic friction of jointed rockmass. And then, establish the quantitative method to describe the relation of the information of acoustic frequencies and thermal radiation to the critical states of rockmass stick-slip behaviors.The effects of interfacial viberating properties of rockmass to dynamic friction strength are further studied on this experimental system. The research is helpful in the comprehensive understanding of the earthquake mechanism, in the study of micro-earthquake and rock burst in hydraulic engineering,tunnel engineering,and mining engineering, and geophysical exploration for engineering and other fields.It has very important practical significance.

岩体摩擦本构关系的研究是地震孕震及板块滑动研究中的热点问题之一,但目前主要集中于滑动摩擦特性的揭示。本项目申请试图建立测试节理岩体动摩擦全过程中声发射和产热等物理力学特性的实验技术，即基于大口径的Hopkinson压杆（SHPB）试验装置研制多点声发射和多点红外测温系统，从而探索节理岩体从"波致"（wave-induced）摩擦到"惯性"摩擦到"滑动"摩擦这一动摩擦全过程中声频和热等信息的演化规律，由此建立由声频和热信息定量描述岩体粘滑转换的临界状态的方法。在此基础上，研究界面振动特性对摩擦强度的影响。该研究对于地震机制的认识、对于水利工程、矿山工程和隧道工程中的微地震和岩爆研究、对于工程物探等领域有着十分重要的实用意义。

岩石节理面动摩擦特性的研究是地震预测的研究热点之一，本项目研究对岩石节理面从“波致摩擦”到“惯性摩擦”阶段的性能进行了系统的研究，对揭示地震的形成规律有重要的理论意义，所取得的主要成果如下：（1）基于平板斜撞击、霍普金森杆束系统等冲击动力学实验装置，结合杆束系统的节理滑移实验技术、基于小波分析的多点声发射实验技术、多点红外测温技术等三类技术系统研究了岩石节理面从 “波致摩擦”向“惯性摩擦”性状转化的声发射和产热等物理力学特性。波致摩擦过程节理面局部具有较大的非均匀变形，这种非均匀性导致的局部破碎的动态发展影响节理面的摩擦特性；节理面滑移产生的声发射信息主要集中在较高频率范围，例如在78.25~312.5kHz，而对应的产热的发展过程与声发射基本一致，其温度变化量级为0.01℃，主要集中在较低频率范围。此特性国内外尚无报导。（2）基于广义Dick定律形式，建立了研究节理岩体从“波致摩擦”到“惯性摩擦”到“滑动摩擦”的理论模型，应用此模型对花岗岩、碳化硼粉末、碳化硼块体等三类材料由于局部化变形导致的破裂发展规律进行了弛豫-扩散特性研究，验证了该模型的适用性。此类研究国内外尚无报导。（3）建立了岩石节理的多尺度离散元模型，对复杂节理界面动摩擦性能进行了较系统研究，探讨了节理细微观形态、节理面夹杂物对动摩擦性能的影响，形成了考虑颗粒破碎演化的较可靠的数值分析方法。(4)建立了压剪联合冲击、真三轴静载的岩石动态实验、细观冲击实验等从细微观尺度到宏观尺度的研究岩石节理复杂应力状态下动力学性能的较系统的实验设备和实验技术。相关技术国内外尚无报导。