低频强动力扰动作用下深井巷道围岩锚固体失稳机制

Damage， spalling， caving， even closure of surroungding rock in deep roadway with bolting support results from low frequency strong dynamic disturbance generated by rock burst or blast. Howerver， universal approaches have not formed. Field experiments on attenuation law， characters of frequency spectrum and energy of low frequency shock wave will be carried out for elastic zone， plastic zone and fracture zone of roadway surrounding rock; and energy formula of shock wave in roadway surrounding rock will be created. And rock burst type of roadway will be classified. Based on field test， damage law evolution of interfaces of resin-bore wall， resin-bolt and potential fracture in rockmass will be studyed. And discriminant of anchorage system instablity will be established. Relation of strain-stress， loads of anchorage system and bolted body fracture character of detached anchorage body with bolts inpacted by shock wave combined with static load will be studyed. Damage evolution related with bearing structure critical instability will be disscussed. Relational expression with interface damage， working condition of components of anchorage system and bearing structure critical instability will be built， and critical instability of criterion of anchorage system and bearing structure will be established. To sum up above researches， classificationScheme of surrounding rock stability with bolts on the condition of low frequency strong dynamic disturbance and support strategy will be proposed. The research can provides theroetical support for bolting roadway surrounding rock acted by strong dynamic disturance in deep mining.

深井开采过程中，冲击地压所诱发的低频强动力扰动，导致锚杆支护巷道围岩损伤、片帮、冒落甚至闭合，然而目前尚未形成普适性的应对措施。现场监测低频冲击波在锚杆支护巷道围岩弹性区、塑性区和破碎区内的衰减规律、频谱特征和能量特征，对巷道冲击地压类型进行分类。在现场测试的基础上，研究锚固系统在低频强动力扰动作用下，树脂-孔壁、树脂-锚杆及潜在岩体破坏界面的损伤演化规律，建立锚固系统临界失稳的判别式。研究静载和低频强动力扰动组合作用下，群锚锚固分离体的应变-应力关系、锚固系统载荷和锚固体破坏特征；研究巷道围岩锚固系统中锚固界面损伤演化与巷道围岩锚固体承载结构临界失稳的联系，建立界面损伤、锚固系统各构件工况与锚固体承载结构临界失稳的关系式，建立承载结构临界失稳的判别准则。提出低频强动力扰动作用下锚杆支护巷道围岩稳定性分类方案和支护对策。为冲击地压作用下，深井锚杆支护巷道围岩控制提供理论支撑

本项目采用现场调研、数值模拟、相似模拟和理论分析方法研究了冲击地压作用下，锚杆支护巷道围岩的动态响应规律，结论表明：冲击地压发生时，主震振幅较大，持续时间较长，低频成分所占比例较大，频带较宽，大能量波形主频集中在0~40Hz之间；动载作用下，影响巷道围岩稳定性的因素依次为，即ⅴ类岩石条件下，动态扰动频率20Hz 、入射角0°，峰值载荷40MPa，巷道变形最大。动态拉拔下，锚杆轴向应力分布与静态拉拔下分布形式基本相同；峰前和峰后应力分布没有明显界限，随着加载速率的增大，各界面剪应力会直接由峰前分布形式迅速变化为峰后分布形式；加载时间与剪应力呈正比，诸界面应力分布与静态拉拔下的分布形式基本相同，加载时间较长时，诸界面应力峰值会相继出现向深部转移的现象；随着拉拔速率的增大，锚固体峰值位移逐渐增加，所对应的峰值载荷逐渐增加，但增加幅度随加载速率增加而趋缓；拉拔速率一定时，锚固段逐渐向里脱黏破坏，孔壁的粗糙度对峰后的残余粘结力有较大的影响。采用相似模拟实验研究了动态载荷对锚杆支护巷道围岩的作用，结论表明：扰动位置距巷道中心越近，加速度和动态应力峰值越大；施加载荷至0.22MPa附近时顶底板及左帮静态压力达到最大，巷道顶底板及左帮围岩处于极限平衡状态，之后随着压力的增大，围岩破碎和扰动后巷道围岩破坏规律。所得结论对冲击地压、爆破载荷作用下的巷硐围岩稳定具有一定的借鉴意义。