深井高瓦斯破碎煤岩体巷道非稳态演化力学机制及二次稳定理论

Under complex geological conditions, deep-well & high-gas mining roadway suffer various stress, surrounding rock characterized with loose and broken structure, supporting common failure, maintenance cost increased, safety accidents always occurred. The field investigation, the experimental research and the theoretical analysis and other means be used to reveal deformation and instability mechanism path of coal and rock mass in process of stress release; to establish non-linear multi factor multi field coupling mechanics model of deep well high gas coal and rock mass; to study inhomogeneous deformation of layered rock mass, surrounding rock damage, coal and gas coupling main stress partial size and direction on the plastic zone boundary formation; to construct mechanics evolution model of plastic zone change to non steady state; to propose equivalent parameter identification model and calculation method of fractured coal and rock mass; to establish constitutive equation of fractured coal and rock mass limit bearing capacity and spatiotemporal nonlinear attenuation; to derive second stability conditions and safety factor of fractured coal and rock mass and bearing body; to put forward anchor body strength indexes of the primary support and the second support; to construct constitutive equation of fractured coal and rock mass bearing body mechanical parameters of “support + surrounding rock” and displacement and deformation time of surrounding rock; to analyze deformation mechanism and long-term stability of bearing body in the engineering behavior and to provide a theoretical basis for stability control in similar conditions.

复杂地质条件下深井高瓦斯回采巷道受各种应力作用，围岩多表现为松散破碎结构，支护普遍失效，维护成本增加，安全事故不断发生。本项目采用现场调查、实验研究和理论分析等手段揭示煤岩体在应力释放中变形与失稳的主要机理路径，建立深井高瓦斯煤岩体的非线性多因素多场耦合力学模型，探究深井高瓦斯层状煤岩体不均匀变形、围岩损伤、煤与瓦斯耦合主应力偏量大小及方向等对塑性区边界形成的力学机制，构建塑性区向非稳态转变的力学演化模型，提出深井高瓦斯巷道破碎煤岩体的等效参数识别模型和计算方法，建立深井破碎煤岩体极限承载能力与时空非线性衰减的本构方程，推导破碎煤岩体和承载体的二次稳定条件和安全系数，提出初次支护和二次支护后的锚固体支护强度指标，构建深井高瓦斯破碎煤岩体“支护+围岩”承载体力学参数与围岩位移和变形时间之间本构方程，分析承载共同体在工程行为中的变形机制及长期稳定性，为类似条件巷道的稳定性控制研究提供理论依据。

针对深井高瓦斯破碎煤岩体巷道非稳态演化力学机制及二次稳定理论等问题，采用现场调查、实验研究和理论分析等手段，揭示了深井高瓦斯破碎煤岩体的力学特性，探讨了巷道围岩失稳模式和煤岩体的损伤特征，获取了瓦斯应力场形成的偏应力场分布特征及其动态演化规律；分析了深部高地应力和高瓦斯渗透压力共同作用下围岩力学作用过程和失效的内在联系，构建了含瓦斯煤岩的Biot型本构方程，揭示了不同瓦斯煤岩体内孔隙、裂隙分布情况下的煤岩体力学参数规律；提出了破碎煤岩体受压主要有偏芯挤压和对芯挤压两种力学机制，分析了深井高瓦斯岩石损伤演化的统计本构模型和等效参数估算方法；建立了煤岩体巷道围岩失稳破坏与二次稳定判别条件；考虑锚固体的强度效应，推导了初次支护和二次支护后的锚固体支护强度指标，构建了基于改进的Nishihara模型的非线性流变本构模型，揭示了支护结构在围岩变形中的变形机制及稳定性，提出了相关控制原则和技术体系。