水中高压电脉冲放电致裂不同强度煤体效果研究

为探明高压脉冲放电技术对不同物理力学特性煤体的致裂效果,用相似材料替代煤岩地层,运用高压脉冲放电系统对不同强度的相似材料进行水中放电致裂实验并分析致裂效果。研究表明:宏观来看,试样强度越大,形成贯通裂纹所需脉冲放电次数越多,所需要的能量也就越大;试样强度越小,形成贯通裂纹后的试样钻孔内部裂隙发育越丰富。裂纹的扩展程度都呈现三个阶段,即准备阶段、发展阶段和破环阶段;但随着试样强度的增大,准备阶段的次数增加,即需要更大能量为发展阶段做准备。裂纹的扩展速度都呈现出"慢-快-慢"的趋势。微观上来看,钻孔周围的裂纹随实验次数增加明显变宽,直至破碎,而这种现象随着距钻孔的距离越大越不明显。

Research On Effect Of High-Voltage Electric Pulse Discharge In Water On Cracking Different Strength Coal

In order to prove the cracking effect of high-pressure pulse discharge technology on coal bodies with different physical and mechanical properties, similar materials were used to replace coal rock formations, and the high-voltage pulse discharge system was used to perform underwater discharge cracking test on similar materials with different strengths and the experimental results was analyzed. The studies show that from a macro perspective, the greater the strength of the sample, the greater the number of pulse discharges required to form a through crack, and the greater the energy required. The smaller the strength of the sample, the more abundant the internal crack development in the drilled hole after the formation of a through crack. The degree of crack propagation has three stages, namely the preparation stage, the development stage and the ring-breaking stage. However, as the intensity increases, the number of preparation stages increases, which requires more energy to prepare for the development stage. The crack growth speeds show a "slow-fast-slow" trend. From a microscopic point of view, the cracks around the drill hole widen significantly with the increase of the number of experiments until they break, and this phenomenon becomes less obvious with the distance from the drill hole.