深部大变形煤巷层状顶板蝶叶塑性区致冒机理

As coal mining gradually becomes deeper, the original rock stress and tectonic stress rises, and the surrounding rock stress of the corresponding excavation engineering is more prominent, the majority of coal roadway roof appears failure characteristics of large deformation, which causes high roof falling potential risks. So layered roof stability of deep large deformation coal roadway needs to be further researched urgently. Based on unclear mechanism, frequent roof falling accidents and maintenance difficulties of layered roof stability of deep large deformation coal roadway, the application uses integrated research methods, such as theoretical analysis, computer numerical simulation, laboratory test and field measurement to study on distribution, morphological characteristics and propagation rules of butterfly plastic zone of deep large deformation roadway. The study takes butterfly plastic zone theory of roadway surrounding rock as the main line. The research focuses on the internal relation of distribution of butterfly plastic zone of roadway roof and malignant expansion and rock beam fracture instability of different combination layered rock. It reveals roof falling mechanism of butterfly plastic zone in layered roof of deep large deformation coal roadway, and acquires key influencing factors and determination method of roof rock beam fracture instability caused by roof butterfly plastic zone of deep large deformation roadway, which provides theory and control method for layered roof stability control of deep large deformation coal roadway.

随着煤矿开采逐步向深部发展，原岩应力和构造应力也随之升高，相应的采掘工程围岩应力更为突出，多数煤巷顶板出现大变形破坏特征，存在高冒顶隐患风险，深部大变形煤巷层状顶板稳定性亟待深入研究。本申请针对深部大变形煤巷层状顶板破坏机理不清、冒顶事故频发、维护困难等问题，采用理论分析、计算机数值模拟、实验室试验和现场实测等综合研究方法，以巷道围岩蝶形塑性区理论为主线，研究深部大变形巷道围岩蝶形塑性区分布、形态特征与扩展规律，重点探究巷道顶板蝶叶塑性区分布形态和恶性扩展与不同组合层状岩体顶板岩梁破断失稳内在联系，揭示深部大变形煤巷层状顶板蝶叶塑性区致冒机理，获得深部大变形煤巷顶板蝶叶塑性区诱导顶板岩梁破断失稳的关键影响因素及判定方法，为深部大变形煤巷层状顶板稳定性控制提供理论依据。

随着煤矿开采逐步向深部发展，原岩应力和构造应力也随之升高，相应的采掘工程围岩应力更为突出，多数煤巷顶板出现大变形破坏特征，存在高冒顶隐患风险，深部大变形煤巷层状顶板稳定性亟待深入研究。研究深部大变形巷道围岩蝶形塑性区分布形态与扩展规律，重点探究深部大变形煤巷顶板蝶叶塑性区与顶板岩梁破断失稳的内在联系，揭示深部大变形煤巷层状顶板蝶叶塑性区致冒机理，获得深部大变形煤巷顶板蝶叶塑性区诱导顶板岩梁破断失稳的关键影响因素及判定方法。主要成果如下：.（1）获得了深部大变形采动巷道围岩蝶形塑性区分布形态与扩展规律，竖直向主应力大时，蝶叶破坏在帮部，水平方向主应力大时，蝶叶破坏在顶底板，受叠加采动影响时，主应力方向发生偏转导致巷道围岩非对称性变形破坏，随着主应力比值的略微变化，蝶叶塑性区成倍扩张。.（2）揭示了深部大变形煤巷层状顶板蝶叶塑性区致冒机理，蝶叶破坏并发生恶性扩展产生的“分区破坏膨胀力”作用在顶板中位岩层上，顶板浅部岩层临空面在膨胀力作用下产生大变形，变形达到一定程度后顶板危险区即蝶叶塑性区与层状岩体交互区岩体便会产生强烈的相互拉剪作用，巷道帮部蝶叶破坏增加了巷道实际跨度，相对减小了岩层的极限垮落步距，使中位岩层更容易发生失稳破断。.（3）获得了深部大变形煤巷顶板蝶叶塑性区诱导顶板岩梁破断失稳的关键影响因素，主要指标为主应力比值、主应力方向、煤层倾角、采动影响系数、岩层厚度、岩层内聚力、岩层摩擦角、开采深度、巷道半径、顶板下沉量以及淋水、断层等因素。.（4）提出了深部大变形煤巷顶板蝶叶塑性区诱导顶板岩梁破断失稳的判定方法，将巷道厚软直接顶蝶叶破裂冒顶高度和复合顶板蝶叶破裂失稳高度的最大值作为巷道冒顶高度值判别巷道顶板冒顶隐患，将其判别技术应用在巷道冒顶隐患分级上，巷道在服务期间稳定性与冒顶隐患级别技术确定级别基本一致，为矿井的安全生产和高产高效奠定了良好的条件。