含共面断续裂隙砂岩样单轴压缩及流变特性试验研究

发布时间：2018-06-13 00:47

本文选题：岩石力学 + 共面断续裂隙岩体　；参考：《重庆大学》2015年硕士论文

【摘要】：由于岩体所赋存环境和荷载作用的复杂性,导致工程建设及后期使用过程中出现了各种变形和失稳破坏问题。长期荷载作用下岩体变形及损伤演化为岩体工程长期稳定性及安全性评价的重要岩石力学问题。本论文依托导师国家自然科学基金面上项目(No.41172243):高残余应力下卸荷破裂硬岩的流变特性及时效扩展机理,开展了含共面断续裂隙岩样单轴压缩、单轴压缩蠕变及单轴循环荷载流变试验研究。较详细的阐述了共面断续裂隙特征、应力水平及循环荷载周期对于岩样单轴压缩流变特性的影响。研究成果对于岩石工程长期稳定性评价有一定的应用意义。主要工作如下:①基于常规单轴压缩试验,分析了完整及含不同倾角的共面断续裂隙岩石的变形及强度参数特征,总结了完整及含不同倾角的共面裂隙岩样变形与破坏异同,进而归纳了含预制共面断续裂隙砂岩样宏观破坏模式。②基于单轴压缩蠕变试验,阐述了蠕变应力水平,共面断续裂隙对蠕变形、损伤破坏的影响特征。研究表明完整及裂隙岩样衰减蠕变时间均随应力水平的增加而减少,裂隙岩样蠕变速率及变形量均高于完整岩样。③基于单轴循环荷载蠕变试验,较详细分析了岩样变形破坏、蠕变曲线、应力-应变曲线及其滞回特性特征。试验表明循环蠕变荷载作用下,岩样经历了微裂隙压密闭合、弹性稳定至损伤变形过程,且循环加卸载过程中存在较明显的滞弹性特性。探讨了应力水平下限及加载周期对循环荷载蠕变特性的影响,分析结果表明循环蠕变荷载作用下降低应力水平下限及延长试验周期均会引起岩样变形的增加。④以含35o预制共面裂隙流变加载试验为基础,对恒载蠕变及循环荷载蠕变两种流变加载方式下的岩样应变量及应变率变化进行了详细对比。发现随在相当的上限应力作用时间内,循环蠕变岩样变形增量均大于恒载蠕变岩样,表明卸载及下限应力保载过程中岩样也存在较强损伤。
[Abstract]:Due to the complexity of the environment and loading of rock mass, various deformation and instability problems have occurred in the process of engineering construction and later use. The deformation and damage evolution of rock mass under long-term load is an important rock mechanics problem for the long-term stability and safety evaluation of rock mass engineering. The Science Foundation Project (No.41172243): the rheological characteristics and aging mechanism of the hard rock under high residual stress unloading and fracture hard rock, the rheological tests of uniaxial compression, uniaxial compression creep and uniaxial cyclic loading are carried out. The characteristics of coplanar intermittent fracture, stress level and cyclic loading period are described in detail. The research results have some practical significance for the long-term stability evaluation of rock engineering. The main work is as follows: 1. Based on the conventional uniaxial compression test, the characteristics of the deformation and strength parameters of the coplanar fractured rock with complete and different dip angles are analyzed, and the complete and different dip angles are summarized. According to the similarities and differences between the deformation and failure of the coplanar fissure rock sample, the macroscopic failure mode of the prefabricated coplanar fractured sand rock sample is summed up. Secondly, based on the uniaxial compression creep test, the creep stress level and the effect of the coplanar intermittent fracture on the creep deformation and damage damage are expounded. The study shows that the decay and creep time of the complete and fractured rock samples are all with the stress. The creep rate and deformation of the fractured rock samples are all higher than that of the intact rock. Thirdly, based on the uniaxial cyclic loading creep test, the deformation failure, the creep curve, the stress-strain curve and its hysteresis characteristics are analyzed in detail. The test shows that the rock sample has experienced the close closure of the micro crack under the cyclic creep load. The effect of the lower limit of stress level and the loading period on the creep characteristics of cyclic loading is discussed. The results show that the decrease of the lower stress level and the extension of the test period will cause the increase of the deformation of the sample. On the basis of the rheological loading test of 35o prefabricated coplanar crevice, the variation of strain rate and strain rate of rock samples under two kinds of rheological loading methods, constant load creep and cyclic loading creep, are compared in detail. It is found that the deformation increment of cyclic creep specimen is larger than that of constant load creep in the time of equal upper limit stress. There are strong damage to rock samples in the lower limit stress protection process.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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