巷道复合顶板塑性区穿透致冒机理研究

When there is a great difference in mechanical properties of roadway roof strata, especially in the case of weak strata in the deep roof, there will appear plastic zone penetration phenomenon, the formation of plastic zone penetration is an important factor of whole roof rupture and even roof fall. Comprehensive research method, such as theoretical analysis, laboratory experiment, numerical simulation and field detection, will be used in this project. Firstly, based on the “butterfly plastic zone theory”, boundaries of plastic zone in the compound roof of roadway will be built and forming the mechanical model to reveal the physical and mechanical nature of the plastic zone penetration distribution in the compound roof of roadway, and to obtain the conditions for the formation of the plastic zone penetration; key influencing factors that will cause penetrated plastic zone appear malignant expansion, such as distribution range increased abnormally and affected layers increased, will be researched at the same time. Secondly, independent technology, such as the self moving rock drilling itinerant video camera, will be used to detect the rupture evolution characteristics and deformation law subtly in situ, and to explore the mechanical process of the penetrated plastic zone causing lower strata without plastic damage ruptured and instable. On these basis, to establish the mechanical model on stability of compound roof and determine its boundary conditions, to reveal the mechanical mechanism of roadway roof fall resulting from plastic zone penetration, to obtain the criteria of roof fall resulting from penetrated plastic zone, and to provide theory basis for roof fall hazards control and early warning in the compound roof of roadway.

巷道顶板岩层力学性质存在较大差异时，尤其在顶板深部存在软弱岩层的情况下，会出现塑性区穿透分布现象，穿透塑性区形成是引发顶板整体破裂甚至冒顶的重要因素。本项目拟采用理论分析、实验室试验、数值模拟和现场探测等综合研究方法。首先，以“蝶形塑性区理论”为基础，构建复合顶板巷道塑性区边界形成力学模型，揭示巷道复合顶板塑性区穿透分布形成的物理力学本质，获取塑性区呈穿透分布的产生条件；同时探究致使穿透塑性区出现分布范围异常增大、波及层位增多等恶性扩展现象的关键影响因素。其次，结合自移式岩层钻孔巡回摄录仪等自主技术，现场精细探测巷道复合顶板破裂演化特征与变形规律，探究穿透塑性区致使下位未发生塑性破坏岩层破裂乃至失稳的力学过程。在此基础上，建立巷道复合顶板稳定性力学模型并确定其边界条件，揭示塑性区穿透分布致使巷道冒顶的力学机理，获取穿透塑性区致冒准则，为复合顶板巷道冒顶隐患控制与冒顶预警提供理论依据。

本项目采用理论分析、实验室试验、数值模拟和现场探测等综合研究方法。首先，以“蝶形塑性区理论”为基础，构建了复合顶板巷道塑性区边界形成力学模型，揭示了巷道复合顶板塑性区穿透分布形成的物理力学本质，获取了塑性区呈穿透分布的产生条件；同时探究了致使穿透塑性区出现分布范围异常增大、波及层位增多等恶性扩展现象的关键影响因素。其次，结合自移式岩层钻孔巡回摄录仪等自主技术，现场精细探测了巷道复合顶板破裂演化特征与变形规律，探究了穿透塑性区致使下位未发生塑性破坏岩层破裂乃至失稳的力学过程。在此基础上，建立了巷道复合顶板稳定性力学模型并确定其边界条件，揭示了塑性区穿透分布致使巷道冒顶的力学机理，获取了穿透塑性区致冒准则，提出了冒顶层次控制方法，为复合顶板巷道冒顶隐患控制与冒顶预警提供理论依据。.经过课题组研究人员三年来不懈的努力，本项目基本取得了预期的科研成果。本项目共发表学术论文17篇，其中SCI收录6篇、EI收录9篇；项目负责人为第一发明人授权发明专利10项、软件著作权3项；获得省部级科研奖励9项。取得了如下创新性成果：.（1）掌握了塑性区在巷道复合顶板中的分布规律，从理论上论证了塑性区在复合顶板岩层中具有穿透特性，获取了穿透塑性区的产生条件，并通过数值模拟分析、现场探测进行了验证。.（2）揭示了复合顶板采动巷道的冒顶机理，提出顶板深部软弱夹层塑性区穿透分布致使下位坚硬岩层发生断裂破坏是冒顶的内在原因。.（3）掌握了采动空间不同位置的主应力大小、比值、方向的差异性特征。.（4）采用巷道顶板密集钻孔窥视、高密度顶板深部位移监测为主的现场探测方法，揭示了巷道复合顶板破裂演化特征与变形规律。.（5）建立了以高延伸性锚杆（索）为主导的顶板层次支护方法，有效保障了顶板整体稳定。