动态围压约束煤矸石混凝土巷旁墩柱增阻大变形机理研究

The balance between the strength/stiffness and deformation capacity of the gob-side support is regarded as a key component to the success of gob-side entry retaining technology in deep mining. The present research proposes a novel hybrid tubular column obtaining the combination behavior of “flexible deformation” and “high strength/stiffness” which is environmental and cost-effective. The novel column consists of an outer tube made of skeleton polyethylene fibre-reinforced plastic (i.e. SRPE) and an infill made of coal gangue concrete. Compared with market available tubular standing supports, the SRPE composite tube confined-coal gangue concrete exhibits the obvious strain-hardening behavior with large deformation capacity. In order to better understand the mechanical characteristics of the novel column, the combination of laboratory tests, theoretical analysis and numerical modelling will be conducted. Both the failure mode and confining mechanism of coal gangue concrete under constant/dynamic confining pressure will be investigated respectively. The equivalent transformation model of the confining force under different conditions (i.e. constant confinement and dynamic confinement) will be used to set up the constitutive equation for coal gangue concrete under the confinement provided by SRPE composite tube. Then, the behavior of SRPE composite tube-confined coal gangue concrete tubular column in real application (i.e. gob-side entry retaining) will be explored through the coupling of FLAC and PFC software to further evaluate the deformation mechanism under different loading conditions. The expected results from the present research can deepen the understanding of the mechanical properties of coal gangue concrete under dynamic confining pressure. Meanwhile, the proposed novel hybrid tubular column can enrich the possible selections for gob-side entry retaining in deep mining.

巷旁支护结构强度/刚度与变形能力之间的相互匹配是深部沿空留巷成功的关键。本研究提出一种兼具“柔性让压”和“高强支护”力学特性的经济环保型支护结构，即钢骨架聚乙烯纤维增强塑料（简称SRPE）复合管约束煤矸石混凝土巷旁墩柱。为进一步明确煤矸石混凝土在SRPE复合管提供的动态围压约束条件的增阻大变形机理，本研究拟采用实验室试验、理论分析和数值计算相结合的研究方法，以常围压条件下煤矸石混凝土的应力应变关系为切入点，采用不同约束材料提供动态围压环境，研究动态围压条件下煤矸石混凝土的力学特性。根据常围压和动态围压条件下约束力等效转换模型，建立动态围压条件下煤矸石混凝土本构方程。在此基础上，研究SRPE复合管约束煤矸石混凝土巷旁墩柱在沿空留巷条件下的力学响应特征，揭示新型墩柱结构的变形协调机制。研究成果有助于掌握动态围压条件下煤矸石混凝土的力学特性，为新型巷旁墩柱结构在深部沿空留巷的应用奠定理论基础。

沿空留巷作为煤炭绿色开采技术体系的重要组成部分，在减少巷道掘进工程量、提高煤炭资源回收率和瓦斯控制方面发挥着重要作用。为实现巷旁支护结构强度/刚度与变形能力之间的相互匹配，开发了一种兼具“柔性让压”和“高强支护”力学特性的经济环保型支护结构，即钢骨架聚乙烯纤维增强塑料（简称SRPE）复合管约束煤矸石混凝土巷旁墩柱。为进一步探明新型组合墩柱结构的增阻大变形机理，研究课题综合采用实验室试验、理论分析和数值计算相结合的研究方法，开展了矿用高强度煤矸石混凝土配比设计研究，揭示了煤矸石混凝土的典型破坏模式，掌握了不同煤矸石骨料掺量条件下混凝土单轴抗压强度和弹性模量降低的主要原因；研究了煤矸石混凝土在常围压和真三轴压缩条件下的应力-应变关系，揭示了煤矸石混凝土的三轴压缩力学特性和变形破坏模式；在系统测试不同约束材料拉伸力学性能的基础上，研究了变围压条件下煤矸石混凝土组合结构的力学特性，建立了核心煤矸石混凝土的侧向约束力计算模型，明确了煤矸石混凝土在动态围压约束作用下力学性能增强机制；建立了动态围压条件下煤矸石混凝土的本构方程，揭示了SRPE复合管约束混凝土的力学机理；构建了新型组合墩柱结构-巷道围岩的耦合数值分析模型，研究了沿空留巷条件下新型组合墩柱结构稳定性的影响因素。依托研究课题，发表高水平研究论文8篇，获省部级科技进步二等奖1项，申请国家发明专利5项，授权实用新型专利2项，协助培养硕士研究生2名。