套筒交替压裂作用下岩石力学特性模拟研究  

Simulation Study on Rock Mechanical Properties Under Sleeve Alternating Fracturing Effect

作　　者：韩金明 郭世豪 杨磊[1] Han Jinming;Guo Shihao;Yang Lei(Shandong University of Science and Technology,Shandong Qingdao 266590)

机构地区：[1]山东科技大学,山东青岛266590

出　　处：《山东煤炭科技》2024年第4期140-145,共6页Shandong Coal Science and Technology

摘　　要：为拓宽坚硬顶板强制放顶方法,解决坚硬顶板所引起的围岩应力集中问题,基于弹性力学推导了套筒破岩力学机制,采用PFC3D数值仿真软件,通过改变套筒膨胀路径来分析套筒压裂过程中岩石破裂形态及膨胀力特征。结果表明:多孔套筒压裂过程中,增大钻孔半径、增加套筒数量或减小钻孔间距均能降低岩石开裂所需的注液压力;相较于同步压裂,交替压裂延长了压裂时间,形成了更为复杂的裂隙网络,岩石损伤范围更大;交替压裂降低了压裂过程所需的膨胀压力,加剧了岩石的疲劳损伤,声发射信号呈现多峰值分布,岩石裂缝数目增多;相较同步压裂,套筒交替压裂所产生的耗散能以及耗散能占比更高,对岩石的破坏程度更大。In order to broaden the method of forced roof caving for hard roof and solve the problem of stress concentration in surrounding rock caused by hard roof,the mechanical mechanism of sleeve rock breaking is derived based on elastic mechanics.PFC3D numerical simulation software is used to analyze the rock fracture morphology and expansion force characteristics during sleeve fracturing process by changing the expansion path of the sleeve.The results show that increasing the drilling hole radius,increasing the number of sleeves,or reducing the spacing between drilling holes can all reduce the injection pressure required for rock cracking during the porous sleeve fracturing process;compared to synchronous fracturing,alternating fracturing prolongs the fracturing time,forms a more complex fracture network,and has a larger range of rock damage;alternating fracturing reduces the required expansion pressure during the fracturing process,exacerbates rock fatigue damage,presents a multi peak value distribution of acoustic emission signals,and increases the number of rock fractures;compared to synchronous fracturing,sleeve alternating fracturing generates a higher dissipated energy and dissipated energy proportion and causes greater degree of damage to the rock.

关 键 词：套筒压裂 声发射 裂缝形态 能量演化 

分 类 号：TD327.2[矿业工程—矿井建设]