1:1比例物理模拟研究强动压下凹凸不平表面巷道锚杆受力及加锚体扩容破坏机制

Bolt support method is widely used in the coal mine roadways, which generates pretightening force in surrounding rocks and constrains their displacement through components like plates, steel straps, metal meshes, etc.Considering the unevenness of roadway surface at the coal mines, this study uses the methodologies of in-situ test and laboratory tests. Three dimensional laser is used to scan roadway geographic conditions at the initial tunneling stage and subsequent dynamic pressure caused by mining, three dimensional model of the roadway surface is built and then be printed in 3D; on the base of the underground geological measuring results and 3D printed roadway surface model, similar material proportion will be studied and physical model with a proportion of 1:1 will be built; the independent cylinder of the first domestic bolt support component test platform with a proportion of 1 to 1 will be used to move the physical model to the roadway surface with the same condition as the underground mining face under dynamic pressure caused by mining, multi-parameter online monitoring will be conducted; and this study will analyze the stress characteristics of the bolt and support components under prestress and strong dynamic pressure with uneven roadway surface, make research on the internal stress change of the anchor body (coal and rock body within the anchorage range of the bolt), emerging, expansion and connection mechanism of the cracks and reveal the bolt dilatancy failure law under the influence of strong dynamic pressure to provide scientific theoretical support to improve the roadway bolt support design at the coal mines.

锚杆支护是煤矿巷道主要支护方式，其支护作用通过托板、钢带、金属网等构件对巷道表面围岩施加预紧力和限制位移来发挥。本项目针对煤矿井下巷道表面凹凸不平的常态，采用井下实测、实验室试验的方法开展研究。运用三维激光扫描测量巷道掘进初期及工作面回采动压影响下井下巷道表面形态，构建巷道表面三维空间模型，并进行3D打印；基于井下地质力学实测结果及3D打印巷道表面形态模型，研究相似材料配比，构建1:1比例物理模型；采用国内首套1:1比例锚杆支护构件试验台独立控制油缸将物理模型加载至井下工作面回采动压影响后相同的巷道表面形态，结合多参量在线监测，分析凹凸不平表面巷道预应力施加及强动压作用下锚杆及支护构件受力特征，研究加锚体（锚杆锚固范围内煤岩体）内部应力变化及裂隙的产生、扩展与贯通机制，揭示强动压影响下加锚体扩容破坏规律，为提升煤矿巷道锚杆支护设计的科学性提供理论支撑。

针对煤矿井下巷道表面凹凸不平的常态，采用井下实测、实验室试验、物理模型试验、数值模拟及井下试验方法，围绕巷道支护用高强度锚杆受力特征、围岩变形与扩容破坏机制开展研究，取得了一些新进展。以口孜东矿为试验矿井，井下实测得出试验巷道所测区域最大水平主应力21.84MPa，垂直应力25.12MPa，井下测量得出巷道变形主要为帮部大变形和强烈底鼓，大量肩窝锚杆、锚索破断，托板翻转、钢带撕裂，导致支护破坏与失效。采用1:1比例锚力学性能试验台，对CRMG700型超高强度、高冲击韧性锚杆支护材料开展复合受力状态测试分析，揭示出锚杆的蠕变特性及在拉、剪、扭、弯、冲击复合载荷作用下力学响应规律。物理模拟研究获得了锚杆锚索支护下围岩与支护体受力特征与应力演化规律，并结合三维激光扫描，测试得到了巷道裂隙场分布特征与演化规律，揭示了巷道变形与加锚体扩容破坏机制。数值模拟研究了不同地应力、围岩强度劣化及偏应力等地质力学与生产条件参数对巷道围岩变形影响机制，揭示了锚杆锚索支护巷道围岩受力、变形与裂隙分布规律。提出巷道围岩控制布置方案与参数，并进行了井下试验和矿压监测，锚杆、锚索破断率降低90%，巷道围岩变形量显著降低，项目成果为提升煤矿巷道锚杆支护设计的科学性提供理论支撑。3年来，发表学术论文8篇，其中SCI/EI收录4篇；获省部级科技奖励3项；申请发明专利4项，实用新型专利3项(已授权)。项目负责人姜鹏飞当选中国煤炭科工集团三级首席科学家；项目培养青年科技人才1名，培养博士研究生1名，硕士研究生1名；项目组成员参加国内外学术交流10次。