不同初始损伤和卸荷路径下深埋大理岩卸荷力学特性试验研究

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF DEEP MARBLE UNDER DIFFERENT INITIAL DAMAGE LEVELS AND UNLOADING PATHS

在卸荷速率研究的基础上,较为系统地开展不同初始损伤程度和卸荷路径下深埋大理岩三轴卸围压试验研究。提出新的卸荷力学描述参量:应变围压增量比和统一围压降参数,并结合扩容参数和塑性内变量深入分析初始损伤程度和卸荷路径对深埋大理岩卸荷变形破坏规律的控制作用。通过直观的卸荷破坏概念模型解释卸荷破坏试验中规律的根源和机制。结合深埋隧洞工程,重点探讨初始损伤程度试验规律的重要工程指导意义,为高应力硬岩脆性破坏灾害(如岩爆)的防治提供理论依据。

Based on the research on unloading rates, the triaxial unloading confining pressure tests of deep marble under different initial damage levels and unloading paths are carded out systematically. Novel unloading mechanical parameters are proposed： increment ratio of strain increment to confining pressure increment, and uniform decreasing increment of confining pressure. Combining with the dilatational parameter and plastic internal variables, the control effect of initial damage level and unloading path on failure principle of unloading deformation of deep marble is analyzed. The origin and mechanisms of the principles obtained by the unloading and failure tests are explained through an intuitive conceptual model of unloading failure. Combining with deep tunnel projects, the major guiding significance of the initial damage level principles is discussed. The research results above can provide a theoretical basis for preventing the brittle failure of hard rock under high stress conditions, e.g. rockbursts.