中文摘要：

水压致裂是改变岩体结构的一种天然行为和人为手段。采用F-RFPA2D软件,对水压致裂过程、裂缝扩展形态及注水孔形状和大小、应力条件和岩样强度等影响因素进行了研究。将开始出现声发射的水压称为微裂压力,将声发射急剧增多、裂缝非稳定扩展直至岩样破坏的水压称为破裂压力。岩样尺寸一定时,微裂压力和破裂压力随内孔面积增加而降低,方形孔岩样的微裂压力和破裂压力均小于同面积的圆形孔。微裂压力和破裂压力随围压或岩样强度增加而增加,且其差值随岩样强度增加而增加,理论破裂压力与模拟值趋势基本一致。方形孔的宏观裂纹起裂位置多在角点附近,而圆形孔比较随机。无围压时,宏观裂纹的延伸方向随机;有围压时,宏观裂纹扩展方向大致与主应力方向一致,且沿较大主应力方向的宏观裂纹扩展至岩样破坏,较小主应力方向宏观裂纹不完全发育。研究结果对水压致裂试验和工程实践有一定参考意义。

英文摘要：

Hydraulic fracturing is not only a natural action but also an artificial method to alter rock structure. Hydraulic fracturing process,fracture propagation pattern,and influencing factors including shape and magnitude of inlet hole,stress conditions,and specimen strength were investigated by software of F-RFPA2D. The water pressure that causes occurrence of AE is named initial pressure Pis,while fracture pressure Pcs is the pressure which leads to dramatic increase of AE,and makes macrofractures propagate in instability till rock specimen failure. In the same rock specimen size,Pis and Pcs of rock specimen with circle-shaped hole are greater than those with square-shaped hole in the same hole area; and they increase when inlet hole area decreases. Pis and Pcs increase with the increase of confining pressure and strength of rock specimen; while their differences increase only with rock strength; theoretical fracture pressure Pct and simulated Pcs have almost the same change trend. Macrofractures are usually borne near angle points in rock specimen with square-shaped hole,while the positions are random in rock specimen with circle-shaped hole. Macrofracture propagating directions are random under no confining pressure,but they are in accordance with main stresses directions when confining pressure is not zero; the macrofracture along maximum principal stress direction extend until split rock specimen,while others do not grow completely. Above results are of some significance to hydraulic fracturing tests and engineering practice.