不同温度及应力状态下北山花岗岩蠕变特征研究

发布时间：2018-03-22 02:15

本文选题：岩石力学　切入点：北山花岗岩　出处：《岩石力学与工程学报》2015年06期 　论文类型：期刊论文

【摘要】：基于不同温度及应力状态下的蠕变特性试验,结合三维声发射实时监测信息,开展北山花岗岩的蠕变变形特性以及加载条件(温度、围压和应力状态)对其蠕变破坏过程的影响研究。试验结果表明,北山花岗岩的蠕变破坏包括初始蠕变阶段(瞬态蠕变)、稳定蠕变阶段和加速蠕变阶段3个阶段,在加速蠕变过程中裂纹迅速扩展和积聚是导致岩石最终破坏的主要原因。蠕变试验过程中,声发射累计数和岩石蠕变体积应变的演化趋势整体上具有一致性,但声发射信号对岩石变形破坏的敏感性更强。对试验数据综合对比分析显示,花岗岩蠕变破坏变形受围压的影响显著,围压越高,岩石蠕变破坏前所能承受的变形越大。温度和应力水平对蠕变破坏变形影响并不明显,但可以对蠕变速率造成影响,进而改变岩石的蠕变破坏时间。根据试验结果,在围压2,10,30 MPa条件下,北山花岗岩的蠕变破坏轴向应变平均值分别为0.34%,0.54%和0.71%。
[Abstract]:Based on the creep characteristic test under different temperature and stress state, combined with the real-time monitoring information of 3D acoustic emission, the creep deformation characteristics and loading conditions of Beishan granite are carried out. The experimental results show that the creep failure of Beishan granite consists of three stages: the initial creep stage, the stable creep stage and the accelerated creep stage. The rapid growth and accumulation of cracks in the accelerated creep process are the main reasons leading to the ultimate failure of rock. During the creep test, the accumulative number of acoustic emission and the evolution trend of creep volume strain of rock are consistent as a whole. But the acoustic emission signal is more sensitive to rock deformation and failure. The comprehensive comparison and analysis of the experimental data show that the creep failure deformation of granite is significantly affected by confining pressure, and the higher the confining pressure is, the higher the confining pressure is. The larger the deformation of rock before creep failure, the greater the effect of temperature and stress level on creep failure deformation, but the effect of temperature and stress level on creep failure rate, thus changing the creep failure time of rock. Under the confining pressure of 2 ~ 10 ~ 10 ~ 30 MPa, the average creep failure axial strain of Beishan granite is 0.34% and 0.71%, respectively.
【作者单位】：核工业北京地质研究院中核集团高放废物地质处置评价技术重点实验室;四川大学水利水电学院;
【基金】：国家自然科学基金资助项目(11202069,51374148)
【分类号】：TU45

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