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利用岩石力学伺服试验机,对尺寸为80 mm×160 mm×30 mm的断续三裂隙砂岩试样进行了单轴压缩试验,研究了岩桥倾角2对断续三裂隙砂岩(=30°和1=60°)强度破坏和裂纹扩展特征的影响规律。与完整砂岩试样相比,断续三裂隙砂岩试样应力-应变曲线显示了较多的应力跌落,其峰值强度也呈显著降低趋势,但降低程度与2密切相关,随着2从75°增加到90°,峰值强度从82.04 MPa降低到77.82 MPa,而当2从90°增加到120°,其峰值强度无明显变化。完整砂岩试样呈现轴向劈裂脆性破坏,而断续三裂隙砂岩试样是由许多从裂隙尖端产生的裂纹扩展与汇合,导致了其失稳破坏。通过照相量测技术,探讨了2对断续三裂隙砂岩试样裂纹扩展特征的影响:2为75°、90°和105°的断续三裂隙试样中裂隙①、③和②、③之间均出现了贯通,而裂隙①、②之间无任何贯通;2为120°的断续三裂隙试样中裂隙①、③和①、②之间均出现了贯通,而②、③之间无任何贯通。最后给出了断续三裂隙砂岩试样宏观变形特性与裂纹扩展过程之间的关系。
Uniaxial compression tests were carried out on rock samples of intermittent three fractured sandstone with the size of 80 mm × 160 mm × 30 mm by using a rock mechanics servo testing machine. The effect of rock tilt angle on the fractured three fractured sandstone (= 30 ° and 1 = 60 °) strength failure and crack propagation characteristics of the law. Compared with the intact sandstone samples, the stress-strain curves of intermittent three fractured sandstone samples show more stress drop and the peak intensity also decreases significantly, but the degree of reduction is closely related to 2, with the increase of 2 from 75 ° Increasing to 90 °, the peak intensity decreases from 82.04 MPa to 77.82 MPa, while when 2 increases from 90 ° to 120 °, the peak intensity does not change significantly. The intact sandstone samples show axial fragmentation and brittle failure, while the fractured three-fractured sandstone samples expand and converge with many cracks generated from the crack tips, leading to their failure. Through the photogrammetry technique, the influence of crack propagation on the fractured three-fractured sandstone samples was investigated. The fractures ①, ③ and ②, ③ of the intermittent three-fractured samples with 75 °, 90 ° and 105 ° Between the cracks ①, ② without any breakthrough between; 2 for the 120 ° intermittent triple-fracture specimens in the cracks ①, ③ and ①, ② between the appear through, and ②, ③ between Without any connection. Finally, the relationship between the macroscopic deformation characteristics and the crack propagation process of the fractured three-fractured sandstone samples is given.