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深部岩体强度参数的研究相当复杂,与研究尺度、应力状态、应力路径都有关系。以锦屏二级水电站深埋引水隧洞T2b大理岩为研究对象,开展室内标准尺寸岩块岩样、中等尺寸岩石岩样和大尺寸岩体岩样在低–中、中–高、高–极高应力水平下的三轴加、卸载试验,探讨深部岩体强度参数的应力水平效应、应力路径效应和尺寸效应。取得以下成果:(1)获得室内标准尺寸、中等尺寸和大尺寸大理岩岩样在加、卸载应力路径下低–中、中–高、高–极高应力水平下的10组强度参数;(2)大理岩抗剪强度参数随应力水平的变化规律基本相同:随着应力水平的提高,?值逐渐减小、c值逐渐增大,但是,不同尺寸和不同应力路径下,?值和c值随围压应力水平的变化幅度并不相同;(3)相对加载条件,卸载路径下岩体强度参数?值增加,c值减小;(4)在φ50 mm×100 mm至500 mm×500 mm×1 000 mm尺度范围内,大理岩强度参数?值的尺寸效应不明显,而c值的尺寸效应显著。
The research on the strength parameters of deep rock mass is quite complicated, which has relations with the research scale, stress state and stress path. Taking the T2b marble of the Jinping second stage hydropower station as a research object, the standard rock mass samples of middle size, rock samples of medium size and rock samples of large size rock mass are studied in low, middle, middle, high, Three-axis loading and unloading test under high stress level to investigate stress level effect, stress path effect and size effect of deep rock mass strength parameters. The results are as follows: (1) Ten sets of strength parameters of indoor standard size, medium size and large size marble rock samples under low, medium, medium - high and high - very high stress levels under loading and unloading stress paths were obtained. 2) The law of shear strength of marble varies with the stress level basically the same: with the increase of stress level, the value decreases gradually and the value of c increases gradually. However, under different stress paths, (3) Under relative loading conditions, the value of rock mass strength parameter increases and the value of c decreases; (4) In the range of φ50 mm × 100 mm to 500 mm × 500 In the range of mm × 1 000 mm, the size effect of the marble strength parameter is not significant, while the size effect of the c value is significant.