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岩石体积变化影响其强度和变形等特性.开展了岩石的常规三轴压缩、疲劳和蠕变试验,分析剪缩和剪胀对岩石完整性、疲劳特性和蠕变特性的影响.研究发现,(1)岩石剪胀随围压增加而减小,剪胀线可用来描述岩石完整性变化情况;(2)循环荷载试验中,剪缩区域内岩石变形模量随循环次数增加而变大,而剪胀区域内变形模量随循环次数增加而变小;(3)蠕变试验中,剪缩区域内岩石轴向应变随时间增加而减小;而剪胀区域内轴向应变随时间增加而增加,蠕变速率随时间增加而减小;(4)三轴剪切应力作用下,岩石表现出三种不同性质:剪缩、硬化剪胀和软化剪胀,不同性质区域内岩石变形宏细观机制不同.岩石在剪缩范围内将不会发生疲劳和蠕变破坏,而在剪胀范围内则会发生疲劳和蠕变破坏.
The change of volume of rock affects the characteristics of its strength and deformation, etc. The conventional triaxial compression, fatigue and creep tests of rock are carried out to analyze the influence of shear and dilatancy on the integrity, fatigue and creep characteristics of rock.It is found that ( 1) The dilatancy of rock decreases with the increase of confining pressure. The dilatancy line can be used to describe the change of rock integrity. (2) In the cyclic loading test, the deformation modulus of rock in the area of shear shrinkage increases with the increase of cyclic number, (3) In the creep test, the axial strain of the rock decreases with the increase of the time in the creep test and the axial strain in the dilatancy zone increases with the increase of the time And the creep rate decreases with the increase of time. (4) Under triaxial shear stress, the rock shows three different properties: shear shrinkage, hardening dilatancy and softening dilatancy. Unlike the mechanism of view, rock will not experience fatigue and creep damage within the shear reduction range, while fatigue and creep damage occur within the dilatancy range.