冲击载荷作用下巷道围岩锚固体承载特性试验研究

The bearing characteristics of anchoring structure and its developing law under impact load which comes from phenomena like rock burst, gas outburst and etc is one of key problems of stability control of dynamic disaster roadway. The relationship between anchorage unit dynamic load bearing capacity and affecting factors such as dynamic loading energy and speed and anchor bolt strength, yielding capacity, pre stress and support density is to be studied by orthogonal physical simulation test, from which the weight of affecting factors and anchorage unit dynamic bearing capacity expression will be obtained by statistic method and the affecting mechanism of anchoring condition to anchorage unit dynamic bearing capacity will be revealed. Anchorage unit constitutive model under dynamic load will be developed by studying the relationship between stress and strain in the process of loading, from which the impact mechanical developing law during the resistance of anchorage unit to dynamic load will be revealed. The distribution and developing law of three dimensional spatial fracture in anchorage unit under dynamic load will be obtained by means of ultrasonic phased arrays. The fractal characteristic of anchorage unit fragmentation after dynamic load will be obtained by statistics and the affecting law of anchoring condition and impact load to anchorage unit dynamic bearing capacity will be studied, by which anchorage unit dynamic bearing mechanism will be revealed from the point of damage and energy dissipation. The research achievement will provide theoretical direction for prevention and control of roadway dynamic disaster.

冲击地压、岩爆及瓦斯突出等动力现象产生的冲击载荷作用下锚固结构力学行为与演化规律是动力灾害巷道围岩稳定控制的关键科学问题之一。采用正交物理模拟试验方法定量研究冲击能量、冲击速度以及锚杆锚固力、让压特性、预紧力、支护密度对锚固体冲击载荷承载能力的影响规律，统计确定影响因素权重及锚固体动态承载能力表达式，揭示锚固条件对锚固体动态承载性能作用机理；根据试验研究冲击载荷施加全过程锚固体应力与应变之间的关系，建立冲击载荷下锚固体本构模型，揭示锚固体抵抗冲击载荷全过程动态力学演化机制；基于超声相控阵技术，获得冲击载荷下锚固体内部三维空间裂隙分布及演化规律，统计掌握冲击后锚固体块度分形特性，探究锚固条件以及冲击载荷对锚固体损伤及能量耗散特征的影响规律，从能量耗散和损伤角度揭示冲击载荷下锚固体承载机制；研究成果可为巷道动力灾害防控新技术提供理论指导。

随着地下工程深度的增加，动力灾害发生的频次越来越高，危害越来越大。巷道锚固支护结构具有自然的柔性特征可以增强对冲击动力余能的耗散作用，可以为深部围岩提供支护阻力，降低冲击地压发生的可能性。锚固体作为锚杆与围岩组成的锚固承载结构的几何及力学基本组成单元，其在冲击载荷作用下的变形破坏及力学特性对于冲击地压灾害巷道围岩稳定性控制问题无疑具有至关重要的意义。.本项目以高应力冲击矿压巷道锚固围岩破坏失稳为背景，利用约束围压SHPB锚固体动态力学特性试验系统及自主研发的恒等刚度直剪试验系统，紧紧围绕锚杆对围岩强化机理这一关键科学问题开展研究。通过开展约束围压条件下SHPB锚固体动态力学特性试验，研究围压、冲击能量、加载速率以及冲击次数对锚固体变形破裂特征、动态承载力学特性影响规律，建立锚固体比能量吸收值、损伤度与影响因素之间的关系，揭示锚固体动态承载力学演化机制与能量耗散机理；批量开展不同截面含钢率条件下锚固体恒等刚度剪切试验，获得了法向力、锚杆支护密度对围岩峰值及残余强度强化定量规律，为巷道定量化支护模拟仿真、理论分析以及新型支护材料研发提供基础；提出了高应力冲击地压巷道围岩卸、调、支综合稳定控制技术，并选择典型冲击地压矿井成功进行工业性试验。