深部高应力岩巷掏槽爆破破岩过程与机理研究

Cut blasting is the key of blasting tunneling, and the high geostress conditions in deep rock roadway have very obvious influence on cut blasting. Till now, as the geostress effect have not been properly considered for the blasting parameters design in the deep roadway tunneling, there usually are problems such as low utilization ratio of borehole, slow tunneling speed, poor roadway quality and so on. In this project, combined with theoretical analysis and numerical simulation, by using self-made loading device transformed by electro-hydraulic servo actuator to simulate different high stress state, model tests are used as the main method to study the rock fragmentation process of rock roadway cutting blasting under deep high stress condition. And the constitutive model of blasting damage in rock cutting area under the synergistic effect of high geostress, explosion stress wave and detonating gas will be established, and then, the failure criteria of rock in cut blasting cavity can be presented. Building the trajectory equation of flying rock, blasting pile fractal function, blasting fragmentation distribution function are also the aims of this project. Meanwhile, do the inversion of deep rock roadway cutting blasting process according to the blasting effects. So that the calculation method of cut blasting parameters design in deep rock roadway will be obtained, the deep high stress rock roadway can be classified, and the design system of deep rock excavation blasting parameters is established. The study achievements can provide scientific basis for research on blasting mechanism and optimal design of rock roadway under deep high stress, and the achievements are also of great use in reducing deep mine accidents and increasing product safety and tunneling efficiency.

掏槽爆破是井巷爆破掘进的最关键技术，而深部岩巷所处的高地应力场直接影响掏槽爆破的效果。由于目前深部井巷掘进的爆破参数计算设计难以准确考虑地应力场的作用，所以经常出现爆破炮孔利用率低、掘进速度慢和成巷质量差等问题。本课题以模型试验为主要研究手段，通过自制三向电液伺服作动器加载装置模拟不同高应力状态，结合理论分析和数值模拟方法，研究深部高应力条件下的岩巷掏槽爆破破岩过程与机理，建立高地应力场与爆炸应力波及爆生气体协同作用下的掏槽区岩体爆破损伤本构模型；提出掏槽腔岩体的破坏判据；构建爆破飞石运动轨迹方程、爆堆形状和爆破块度分布特征函数，根据爆破效果反演掏槽区岩体爆破破岩机理，得出深部岩巷掏槽爆破参数计算方法，建立不同高应力条件下的深部岩巷掏槽爆破参数设计体系。研究成果可以为深部高应力岩巷掘进爆破机理研究、优化设计提供科学依据，对于提高掘进效率和减少深部矿井安全事故都具有重大理论意义和应用价值。

深部岩巷所处的高地应力场直接影响掏槽爆破的效果，进而影响井巷爆破掘进。本项目基于多座高应力矿井深部岩巷现场监测成果，得出了不同岩性巷道掘进工作面区域内高地应力分布特征，并根据现场地应力特征和岩石动静态力学参数，确定了不同高应力状态下掏槽爆破模型试验方法和技术参数。结合理论分析、现场试验测试、模型试验、数值模拟研究等手段，提出了综合考虑岩巷埋深、地应力大小和侧压比、深部岩体物理力学性质等多种影响因素的深部岩巷掏槽爆破参数理论计算模型以及掏槽爆破参数设计体系。结果表明：（1）三轴压缩条件下岩石试样主要呈现出脆性张裂破坏和剪切破坏，岩石应力-应变曲线表现出明显的脆性和应变软化特征。（2）提出了高应力条件下爆后飞石运动轨迹方程、爆堆分布和爆破块度分布计算方法。基于能量释放率准则，提出了细观损伤状态下掏槽腔岩体的破坏判据和本构方程。掏槽区岩体的破坏是爆炸能量场与破坏能量场耦合作用于岩石能量阈值场的结果，当能量达到某一阈值，岩石将发生断裂、破坏或愈合。（3）通过自主设计的爆破模型试验系统模拟深部应力环境，进行了相似模型掏槽爆破试验。结果显示，围压作用下抑制了模型表面裂纹扩展，掏槽爆破需要更多的能量克服岩石的夹制作用形成槽腔，小块度碎块均较少；随着炸药单耗的增加，抛掷距离增大，爆堆高度也有所降低。（4）侧压系数的变化对爆炸载荷下炮孔附近损伤形态基本不产生影响，对各炮孔的损伤演化速度和方向具有明显影响。装药孔与空孔的间距对掏槽爆破效果起到关键性作用，空孔与炮孔距离太小容易形成再生岩，炸药利用率低；距离太大则会使空间形成裂纹减少，岩体大块率较高。本项目研究成果在大量矿山深部采掘工程项目中进行了现场试验与应用，实现了深部高应力岩巷的快速高效光面爆破掘进，取得了良好的爆破效果，大大提高了采掘效率，经济效益和社会效益显著，推广应用价值高。