围岩孔内充水承压固液耦合爆破机理及其模型律

Confined blasting of rock with water filling the borehole is a safe and efficient blasting technique. The existence of the borehole-filling water surrounding the explosive charge and the water-soaked zone in the borehole wall distinguishes this technique from common blasting techniques and enables efficient transmission of explosive energy released by detonation. This study focused closely on the borehole-filling water layer and the water-soaked zone in the borehole wall and aimed to discover the mechanism of efficient load transfer by the water surrounding the charge using explosion impact dynamics. First, a water immersion test was conducted on the coal to see how the water pressure and immersion duration affected the thickness of the soaked zone. A dynamic test was performed on the water-soaked coal to analyze the effects of the thickness of water-soaked zone on the dynamic constitution and failure mode of the soaked coal at high strain rates. Then, a confined blasting simulation test was performed to analyze the patterns of wave propagation and load transfer in the borehole-filling water and reveal the mesoscopic mechanism of confined blasting with solid-fluid coupled charge. Later, an orthogonal experiment with multiple factors was carried out. Based on the experimental results, a macroscopic model law was established for confined blasting under the effects of complex factors, providing a basis for parameter determination in confined blasting with water filling the borehole as well as guidance to related experimental design and technical application.

围岩孔内充水承压爆破作为一项安全高效能的爆破技术，孔内装药周边充水层和孔壁围岩浸水层的存在，是其区别于普通装药爆破条件的重要特征，是孔内炸药爆炸高效能充分发挥的关键。本课题紧密围绕核心研究对象——孔内充水层和孔壁浸水层，采用爆炸冲击动力学方法，研究孔内装药周边充水层的高效传载机制；开展承压水作用下的煤岩浸水特性试验，分析浸水层厚度对水介质承压和浸水时长的响应；开展浸水煤岩动态力学试验，分析高应变率条件下的浸水煤岩动态本构及其破坏形态对浸水层厚度的响应；开展孔内充水承压爆破模拟试验，分析充水层内波的传播传载规律，揭示围岩孔内充水承压固液耦合爆破细观作用机理；开展多因素影响下的承压爆破正交试验，建立复杂因素影响下的宏观爆破模型律，为围岩孔内充水承压爆破参数的合理确定提供依据，指导试验设计及技术应用。

坚硬顶板控制一直是我国煤矿岩层控制中的重点和难点问题。伴随煤炭资源开采深度与强度的增加，煤炭高效开发伴生的坚硬顶板事故和灾害问题愈加突出。在此条件下，开展高效的顶板控制技术与机理研究，是坚硬顶板煤层安全高效开采的重要保证。基于此，提出了一种钻孔围岩充水承压爆破致裂技术，借助孔内水介质和浸润改性煤岩的优越传载性能，实现了爆炸高能量的充分利用，并综合多种方法研究了多介质层内的波动传载规律和爆生气体膨胀过程，揭示了孔内充水承压爆破高效破岩机理，为矿井坚硬顶板合理爆破预裂参数的确定提供了依据。针对以上内容取得以下研究成果：.（1）高应变率加载条件下，天然与浸水岩体应力-应变曲线相似，随着浸水时间与浸水压力增加，岩体强度伴随应变率提高呈指数增长。低应变率条件下，天然、浸水岩石的抗压/抗拉强度和应变率之间分别满足指数与对数关系，且随着浸水时间和浸水压力的增加，岩石强度有所降低。综合研究指出，浸水岩石高应变率加载下的脆性与强度均有所增加，但低应变率条件下其强度普遍趋于弱化。.（2）在凝聚态炸药爆轰参数分析基础上，探讨了钻孔水介质层中的波动传载规律及破岩机制，建立了承压水层的波动传载、致裂力学模型，揭示了钻孔充水承压条件下的波动高效破岩机制，并在爆炸波破岩分析的基础上，进一步阐述了爆生气体联合孔内水介质的高效增裂机理。综合研究指出，钻孔内水介质的存在利于波动传载效能的充分发挥，通过适当提高孔内水介质的压力，改善浸水煤岩动态力学特性，有利于煤岩高效致裂效果的实现。.（3）研究了大尺寸工程性岩体承压爆破条件下的孔壁围岩应力、裂隙演化规律，重点探讨了钻孔不耦合装药系数、孔内装药量、孔内水介质承压大小以及空孔存在条件等因素对岩体爆破致裂的影响，得到了影响岩体爆破高效致裂效果的主控因素。.围绕以上内容，发表论文6篇，授权专利6项，出版专著1部，省部级科研获奖2项，培养硕士研究生3名。