低温冻结条件下混合岩力学特性研究
发布时间：2018-12-16 11:55
【摘要】：随着大量寒区岩土工程、人工冻结工程的进行,受到周期性低温作用或长期处于低温冻结状态的寒区围岩,其力学特性与常温状态的差别越来越引起人们的重视,为保证寒区工程的安全性,深入研究冻结岩石的力学性质显的越来越重要。以鞍山地区的矿体主要围岩—混合岩为研究对象,对饱水和干燥两种混合岩试样,进行了系统的单轴、三轴压缩试验,研究分析了冻结温度、围压对饱水和干燥两种含水状态混合岩的变形与强度特性的影响。论文主要研究结果如下:(1)三轴试验中,随着围压的上升混合岩轴向峰值应力呈线性增长趋势。当温度条件为常温时,围压从0MPa增至6MPa试样的轴向峰值应力增长130%,温度条件为-5℃时,增长129%,温度为-20℃时增长155%;在温度降低过程中,两种状态混合岩试样的弹性模量都以抛物线规律增长,饱水试样的弹性模量增大程度更明显,而泊松比随试验温度的降低而不断减小但总体变化幅度较小;混合岩粘聚力随温度的降低线性增大;内摩擦角随温度降低略有增大。(2)饱水状态和干燥状态两种混合岩的轴向峰值应力均随温度的降低而增大且成一定的规律;饱水混合岩对温度更敏感,在温度降低过程中,轴向峰值应力增长更快。不论单轴还是三轴试验,饱水混合岩峰值应力要大于干燥混合岩,且在零下温度环境中,饱水混合岩强度要远大于常温条件混合岩强度。(3)在破坏特性方面,单轴压缩试验中混合岩试样破坏形式是与轴向近似平行的劈裂破坏;三轴压缩试验中主要为剪切破坏,围压较低时,基本上呈宏观单一断面的剪切破坏,且破裂面随温度的降低而越发平滑。
[Abstract]:With the development of a large number of geotechnical engineering and artificial freezing engineering in cold region, people pay more and more attention to the difference between mechanical properties and normal temperature state of surrounding rock in cold region, which is subjected to periodic low temperature action or long-term low temperature freezing state. In order to ensure the safety of cold zone engineering, it is more and more important to study the mechanical properties of frozen rock. Taking the main surrounding rock and mixed rock in Anshan area as the research object, the uniaxial and triaxial compression tests of saturated and dry mixed rock samples were carried out, and the freezing temperature was analyzed. The influence of confining pressure on deformation and strength characteristics of saturated and dry mixed rocks. The main results are as follows: (1) the axial peak stress of mixed rock increases linearly with the increase of confining pressure in triaxial test. When the temperature is normal, the axial peak stress of the specimen from 0MPa to 6MPa increases by 130, when the temperature is -5 鈩，
本文编号：2382289
[Abstract]:With the development of a large number of geotechnical engineering and artificial freezing engineering in cold region, people pay more and more attention to the difference between mechanical properties and normal temperature state of surrounding rock in cold region, which is subjected to periodic low temperature action or long-term low temperature freezing state. In order to ensure the safety of cold zone engineering, it is more and more important to study the mechanical properties of frozen rock. Taking the main surrounding rock and mixed rock in Anshan area as the research object, the uniaxial and triaxial compression tests of saturated and dry mixed rock samples were carried out, and the freezing temperature was analyzed. The influence of confining pressure on deformation and strength characteristics of saturated and dry mixed rocks. The main results are as follows: (1) the axial peak stress of mixed rock increases linearly with the increase of confining pressure in triaxial test. When the temperature is normal, the axial peak stress of the specimen from 0MPa to 6MPa increases by 130, when the temperature is -5 鈩，
本文编号：2382289
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