蠕变作用后大理岩强度与变形特性试验研究

发布时间：2018-04-19 17:52

  本文选题：岩石力学 + 蠕变作用后　； 参考：《岩石力学与工程学报》2017年11期

【摘要】：为研究蠕变行为对岩石力学性质的影响,分别在裂隙压密阶段、弹性阶段、裂隙稳定扩展阶段和非稳定扩展阶段,对大理岩进行不同应力水平和时间的蠕变预处理,卸载后再进行单轴压缩破坏试验,分析不同条件蠕变作用后大理岩强度与变形特性的变化规律,同时提出采用体变速率进行岩石变形阶段划分的新方法。结果表明:(1)裂隙压密和弹性阶段蠕变对大理岩力学性能起强化作用,随蠕变时间增长,强度和弹性模量增大,泊松比减小,且弹性阶段蠕变的强化程度大于压密阶段。裂隙稳定扩展阶段蠕变呈现相反的变化规律,起劣化作用,而岩样在非稳定扩展阶段蠕变预处理时快速破坏;(2)依据扩容速率可将岩石变形过程分为3个阶段,分别为平稳压缩阶段、加速扩容阶段及减速扩容阶段;(3)裂隙压密和弹性阶段蠕变后,大理岩峰值扩容速率随蠕变时间增长略有减小,裂隙稳定扩展阶段蠕变后则随蠕变时间增长显著增大;(4)原始岩样和蠕变作用0 h后岩样的单轴压缩破坏形态以单一剪切面破坏为主。随蠕变时间增长,裂隙压密和弹性阶段蠕变后岩样破坏形态转为沿轴向劈裂破坏,裂隙稳定扩展阶段蠕变后转为剪切、劈裂组合破坏,除几条主裂隙外,还伴随众多次生裂隙。
[Abstract]:In order to study the influence of creep behavior on the mechanical properties of rock, the creep pretreatment of marble with different stress levels and time was carried out at the stage of crack compaction, elastic stage, crack stable extension stage and non-stable extension stage, respectively.After unloading, uniaxial compression failure test was carried out to analyze the variation of strength and deformation characteristics of marble under different creep conditions, and a new method to divide the deformation stages of marble by bulk deformation rate was put forward.The results show that crack compaction and elastic creep strengthen the mechanical properties of marble. With the increase of creep time, the strength and modulus of elasticity increase, and Poisson's ratio decreases, and the creep strength of elastic stage is greater than that of compaction.The creep in the stable extension stage of fracture shows the opposite change law, which plays a role of deterioration, but the rock sample can be divided into three stages according to the expansion rate when the creep pretreatment of the rock sample in the unsteady stage of creep pretreatment. The rock deformation process can be divided into three stages according to the expansion rate.The peak expansion rate of marble decreases slightly with the increase of creep time after crack compaction and creep in elastic stage, which are steady compression stage, accelerated expansion stage and deceleration expansion stage, respectively.After creep at the stable extension stage of fractures, the creep time increases significantly with the increase of creep time) the uniaxial compression failure pattern of the original rock samples and the rock samples after 0 h creep action is dominated by single shear plane failure.With the increase of creep time, the fracture patterns of rock samples after fracture compaction and elastic creep become axial splitting failure, and creep at the stable extension stage of fractures become shear, split combination failure, in addition to several main cracks, there are also many secondary fractures.
【作者单位】： 华侨大学福建省隧道与城市地下空间工程技术研究中心;中国矿业大学深部岩土力学与地下工程国家重点实验室;中国水利水电科学研究院岩土工程研究所;
【基金】：国家自然科学基金项目(51609266,51774147) 中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1701)~~
【分类号】：TU45
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本文编号：1774117