动力扰动下结构面型岩爆孕育发生机理及分析预测方法

The rockburst intensity will be stronger in the rock mass with structure planes, and the extremely strong rockbursts will happen in succession. However, the understanding of the role the structure planes play in rockburst is not clear, and the important dynamic disturbance in practical engineering is seldom considered. Combining with laboratory tests, theoretical and numerical analysis, the project focuses on “mechanical mechanism” and “simulation analysis method” of structure-type rockburst under dynamic disturbance. Based the degradation analysis, the crack evolution law, mechanical response and energy response during the rockburst process will be studied, and the mechanical mechanism of structure-type rockburst hazard under dynamic disturbance will be revealed; through theory analysis, a continuous-discontinuous model which describes the process of evolution and dynamic occurrence for structure-type rockburst will be established, and the critical criterions of evolution phase and occurrence phase will be put forward; the simulation analysis method of evolution and dynamic occurrence process for structure-type rockburst will be built based on the Combined Finite-Discrete Element Method (FDEM), which can simulate the process of dynamic fracture evolution. The results from this project will provide a theoretical basis for the hazard evaluation and prediction of structure-type rockburst in deep-buried underground engineering.

含结构面的岩体发生岩爆的规模和强度往往较大，且容易连续发生强岩爆，但目前结构面对岩爆的作用机制还认识不清，且实际工程中至关重要的动力扰动因素很少被考虑。本项目围绕动力扰动下结构面型岩爆孕育发生“机理”与“分析模拟方法”两大关键科学问题，采取室内试验、理论分析和数值分析相结合的方法，从劣化本质入手研究结构面型岩爆孕育发生过程裂隙演化规律及伴随的力学响应和能量响应，分析结构面对岩爆的诱发机制，揭示其孕育发生机理；通过理论分析建立描述结构面型岩爆孕育演化-动态失稳的连续-非连续力学模型，提出孕育阶段和发生阶段临界准则；基于能够模拟裂纹动态破裂演化的有限元-离散元耦合方法 （FDEM），建立结构面型岩爆孕育演化和动态失稳过程分析模拟方法，为深埋地下工程结构面型岩爆灾害分析预测提供理论支撑。

岩爆作为一种深部地质灾害影响很大，尤其是结构面型岩爆机理认识不清，实际工程中至关重要的动力扰动因素很少被考虑。本文以淮南新庄孜矿为工程背景，通过对采自新庄孜矿的砂岩开展三轴加卸荷试验，研究砂岩在卸荷条件下的强度变形特征、能量运移转化机理以及破坏模式，借此对岩爆孕育发生机理进行深入探索；在卸荷试验的基础上，提出卸荷条件下适应性更强的强度准则和本构模型，并尝试性地提出了岩石脆性跌落系数与岩爆倾向性的关系；从劣化本质入手研究结构面型岩爆孕育发生过程裂隙演化规律及伴随的力学响应和能量响应，分析了结构面对岩爆的诱发机制；在系统总结已有岩爆倾向性数值指标的基础上，提出了岩爆能量释放率指标RBERR，并将其应用到岩爆工程实例中验证指标的合理性。将试验和理论成果应用到淮南新庄孜矿62采区，预测岩爆可能发生的位置和强度，为后续的工程支护提供可靠依据。