深部巷道软弱围岩-约束混凝土支护相互作用机理研究

The rheological properties of soft surrounding rock in deep roadway are obvious, it lasts long time, the destructive zone is large, its integral strength is low and surrounding rock is hard to be controlled. The basic reasons for the problems are that the mechanism of deformation and destruction of surrounding rock and interaction between surrounding rock and supporting system is not clear. . This project is intended to take the typical deep mine as the engineering background, nonlinear and visco-elastoplastic rheological model, which is applicable to the soft rock of deep roadway, is established, the contrast test of three-dimensional rheological model is developed, rheological failure mechanism of surrounding rock in deep roadway is researched, the external load-calculating model of deep surrounding rock is built. Meanwhile, based on unequal rigidity mechanical model of confined concrete arch center, ultimate bearing capacities and yieldable node characteristics are researched in order to get the ultimate bearing capacities and mechanics criterion of unstable failure. Calculation method of arch’s bearing capacity is formed. Full-scale mechanical test of confined concrete arch center is developed, control mechanism and yieldable node mechanism of confined concrete are researched, mechanical calculation model of confined concrete supporting is built. On this foundation, calculation model, which is based on interaction of rheological surrounding rock in deep roadway and confined concrete supporting, is built, the interaction mechanism is revealed. The research results of this project will provide theoretical basis and technical guidance for solving the problem of surrounding rock control of deep roadway.

深部巷道软弱围岩流变特性明显，持续时间长，破坏范围大，整体强度低，围岩控制困难。造成上述问题的根本原因在于该类巷道围岩变形破坏及其与支护体系相互作用机理不明确。. 本项目拟以典型深部矿井为工程背景，建立反映深部巷道软弱围岩的非线性黏弹塑性流变模型，开展三维流变模型对比试验，研究深部巷道流变围岩破坏机制，得到深部围岩外荷载计算模型。同时，基于约束混凝土拱架非等刚度力学模型，推导拱架内力计算公式，开展拱架强度承载和让压节点特性研究，得到约束混凝土拱架强度承载与失稳破坏力学判据，形成拱架承载能力计算方法，并通过拱架全比尺力学性能对比试验，研究约束混凝土控制机制与节点让压机制，建立约束混凝土支护力学计算模型。在此基础上，构建深部巷道流变围岩-约束混凝土支护相互作用计算模型，揭示其相互作用机理。本项目研究成果将为解决深部巷道的围岩控制难题提供理论依据与技术指导。

本项目以典型深井煤矿-赵楼煤矿为工程背景，针对深部巷道复杂条件围岩支护难题，通过现场实测、模型试验、数值分析、室内试验、理论分析及现场试验等手段相结合的方法，对深部巷道复杂条件巷道的变形破坏及围岩控制机理进行研究。项目主要对深部巷道现场监测与典型破坏模式进行研究，建立反映深部巷道软弱围岩非线性的本构模型，通过三维模型对比试验与数值试验，得到了不同支护条件下深部巷道软弱围岩应力与位移演化规律，明确了深部巷道复杂条件软弱围岩控制机制，构建了深部围岩外荷载计算模型。基于此，建立了地下工程约束混凝土高强支护体系，开展了约束混凝土基本构件、节点构件的纯弯、压弯试验，明确了不同条件下节点参数、混凝土强度、截面参数等因素对拱架构件力学性能的影响规律，揭示了节点定量让压机制。建立了不同断面形状任意节数非等刚度拱架力学分析模型，推导了拱架任意截面内力计算公式，得到了拱架强度承载与失稳破坏力学判据，明确了荷载大小、侧压力系数、节点定位角、拱架刚度、节点等效刚度比等参数对拱架承载能力的影响机制，形成了拱架承载能力计算方法。开展了不同巷道断面形状、拱架截面形式、混凝土强度等级和承载条件的约束混凝土拱架数值试验，以及拱架全比尺力学性能对比试验，分析了不同因素影响下拱架承载性能和变形破坏机制，明确拱架关键破坏部位及钢混耦合特性，建立了约束混凝土支护力学计算模型。结合上述试验研究与理论分析，构建深部巷道软弱围岩-约束混凝土支护相互作用计算模型，开展了不同约束混凝土拱架支护条件下的围岩控制数值试验，分析了围岩应力、位移演化规律对拱架高强让压过程的响应特征，揭示了深部巷道软弱围岩-约束混凝土支护相互作用机理。基于深部巷道软弱围岩-约束混凝土支护相互作用机理及上述研究成果，选取典型深部矿井，开展了现场试验，进行了围岩应力变形、支护受力变形现场监测，实现了深部巷道软弱围岩有效控制。项目研究成果为解决深部巷道的围岩控制难题提供了理论依据与技术指导。