无巷旁充填支护条件下沿空留巷顶板压力传递机制及切顶调控机理研究

The gob-side entry retaining undergoes severe ground pressure twice during actual mining, which requires complex maintenance. Therefore,quality of roof control is the key to the retaining of the gob-side entry. The technology of the no-roadside-filling supporting of the gob-side entry retaining refers to a skill that apply no artificial support, but forming an entry-side support by the caved roof. This technology provides a new method to retain the gob-side entry, but some theoretical and implementing problems need to be understood deeper and solved. The project studies key problems of the no-roadside-filling supporting of the gob-side entry retaining, by applying the subjects of rock mass mechanics of underground engineering, elastic-plastic mechanics, and the technologies of physical and numerical modeling. At first, a cutting roof criterionis founded based on the study of mechanical model of surrounding rock structure of the no-roadside-filling supporting of the gob-side entry retaining, and evolution of stress field of surrounding rock. Then the interaction mechanism and evolution progress of supporting and surrounding rockis studied to construct coupling mechanics model of the supports and the ground pressure for the gob-side entry retaining with no roadside filling supporting. Finally, the support resistance of the roadway cutting roof in every period is derived to give the supporting design of cutting roof and the profile of regulation and control. The research provides a theoretical basis for stable control of surrounding rock of the gob-side entry retaining with no roadside filling support.

沿空留巷巷道需要经受两次采动影响,矿压显现强烈,巷道维护难度大，所以有效的顶板控制是能否留巷成功的关键，项目根据实践提出的无巷旁充填支护沿空留巷指在巷旁空间不专门构筑人工支护物，任由顶板垮落形成巷旁支撑。无巷旁充填支护沿空留巷是沿空留巷的新技术，但深层次理论问题亟待解决，本项目采用地下工程岩体力学理论、弹塑性力学理论相结合的方法，借助物理模拟、计算机数值模拟与现场实测相结合的综合手段，对无巷旁充填支护沿空留巷关键科学问题展开研究。基于无巷旁充填支护沿空留巷围岩结构力学模型和围岩应力场演化规律的研究，建立无巷旁充填支护沿空留巷切顶判据，提出切顶判别准则。研究支护与围岩相互作用机制与过程，构建基于支护与围岩耦合作用的无巷旁充填支护沿空留巷顶板支护阻力的力学模型，推演不同阶段巷道切顶支护阻力，提出切顶支护设计方法及切顶调控机理与技术措施，为无巷旁充填支护沿空留巷实现围岩稳定控制奠定理论基础。

沿空留巷巷道需要经受两次采动影响,矿压显现强烈,巷道维护难度大，所以有效的顶板控制是能否留巷成功的关键，项目根据实践提出的无巷旁充填支护沿空留巷指在巷旁空间不专门构筑人工支护物，任由顶板垮落形成巷旁支撑。分析得出如果采用强有力的切顶措施，尽可能在巷旁位置将直接顶甚至老顶切断，可以减少顶板活动对巷道的影响。这样既可以在巷道外侧切断顶板又可以保证巷道顶板稳定，此时切顶阻力是关键，阻力不足无法保证切断顶板，由此切顶阻力必须满足：FC≥ql+FB。老顶处于“给定变形”状态，向采空区方向倾斜引起留巷巷道断面内顶板下沉相差较大，靠近采空区侧巷道顶板下沉量大于靠近煤壁侧的顶板下沉量。采用强有力的切顶措施即可以切断顶板又可以保证巷道顶板稳定。顶板断裂位置影响的主要因素包括倾角、煤层性质、直接顶厚度和性质、老顶厚度和性质以及原岩应力状态等。确定影响次序为：基本顶厚度＞直接顶与采高比值＞倾角＞煤层性质＞直接顶性质＞原岩应力状态＞基本顶性质。提出以极限平衡区在岩体中的位置为依据确定围岩的类别，并以围岩类别与指标值确定巷道的支护形式继而进行支护参数设计。研究支护与围岩相互作用机制与过程，构建基于支护与围岩耦合作用的无巷旁充填支护沿空留巷顶板支护阻力的力学模型，推演不同阶段巷道切顶支护阻力，提出切顶支护设计方法及切顶调控机理与技术措施，为无巷旁充填支护沿空留巷实现围岩稳定控制奠定理论基础。