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基于水压和应力耦合作用下锦屏深部大理岩的三轴蠕变试验,研究了大理岩的变形时效特性、等时曲线特征以及时效破坏机制。研究结果表明,(1)孔隙水压可以增强大理岩的时效变形能力,有水压时的稳态蠕变率大于无水压状态时的稳态蠕变率。(2)裂纹扩容失稳应力强度比可以作为硬脆性岩石是否发生失稳蠕变的门限值,且当应力强度比到达这一门限值时,岩石的失稳概率随着时间发展而陡增。(3)体积蠕变量大于侧向和轴向的蠕变量值,显示脆性岩石扩容蠕变效应特征显著。(4)不同时刻的等时曲线具有明显的相似性,在发生加速蠕变之前,等时曲线基本呈线性特征;而在发生加速蠕变时,等时曲线呈显著非线性特征。
Based on the triaxial creep test of deep marble in Jinping under the coupling of hydraulic and stress, the deformation and aging characteristics, the isochronal characteristics and the aging failure mechanism of marble are studied. The results show that: (1) Pore hydraulic pressure can enhance the aging deformation capacity of marble. The steady state creep rate under water pressure is higher than steady state creep rate under no water pressure. (2) The stress-strain ratio of crack growth instability can be used as the threshold for the instability creep of hard and brittle rocks, and when the stress-strength ratio reaches this threshold, the rock failure probability steep with time increase. (3) The volume creep value is larger than the lateral and axial creep values, which shows that creep effect of brittle rock is significant. (4) The isochronous curves have obvious similarities at different time points, and the isochronal curve has a linear characteristic before accelerating creep, while the isochronal curve shows a significant nonlinear characteristic at the time of accelerating creep.