贺兰口岩画岩石力学特性及典型危岩体的稳定性分析

发布时间：2018-07-01 21:42

本文选题：贺兰口岩画 + 微观特征　；参考：《宁夏大学》2015年硕士论文

【摘要】：贺兰口岩画属于不可移动的,永久暴露于室外的石质文物。由于自然环境以及动植物的各种活动导致严重的破坏,包括岩画表面的残损、风化剥蚀以及由于多种原因产生的危岩块体。为此,本文以贺兰口岩画为研究对象,在对岩画区进行调查的基础上,首先对岩石材料基本微观特性以及物理性质进行分析和测定,得到了岩石密度、孔隙率、吸水率等物理性质和各组成元素的含量以及岩画岩石材料的微观形貌：通过岩石材料的间接拉伸试验(巴西劈裂法)、单轴压缩试验、常规三轴压缩试验和直接剪切试验,初次得到了贺兰口岩画岩石的各项力学参数以及变形破坏特性；通过对“驴羊图”、“手印图”和“石坡岩画群”岩画附近典型危岩体的稳定性分析,获得危岩体稳定性与否的结论。分析发现：(1)岩石样品的密度较高,孔隙率、吸水率较低；组成元素中O和Si元素的含量最高,得出岩石样品主要碎屑为石英；表面不进行处理的岩石样品风化现象十分明显,表现为岩样表面颗粒排布不规则,结构散乱,微裂隙发育较多；而钻取的岩芯表面颗粒排布则相对规整,裂隙发育相对不明显,力学强度也较高。(2)对岩石材料进行间接拉伸(巴西劈裂法)、单轴压缩、常规三轴压缩和单面的直接剪切试验,获得岩石样品的平均抗拉强度为5.6MPa,平均单轴抗压强度190MPa,泊松比0.286左右,平均弹性模量42.99GPa,粘聚力和内摩擦角的值分别为40.66MPa和48.220。试验验证了微观特性对岩石材料强度较高的预测。三轴压缩试验获得岩样的三轴压缩应力应变曲线,曲线可以被划分为四个阶段,即弹性变形阶段、塑性阶段和破坏阶段以及残余强度阶段。岩石的抗剪强度曲线即剪切应力与垂直应力曲线的相关系数R2为0.9861,说明两个应力的线性关系密切,即随着轴压的增大,剪切破坏荷载基本认为是按线性关系增大,剪切—位移曲线也越陡。(3)对贺兰口岩画沟口的三处岩画：“手印图”、“驴羊图”和“石坡岩画群”附近的典型危岩体进行稳定性的计算,发现三处危岩体除“石坡岩画群”附近危岩体状态尚不够明确外,其余两处都处于比较安全的情况。本文的研究成果可为贺兰口岩画的保护工作有指导性的意见。
[Abstract]:Helankou rock paintings are immovable, permanently exposed to outdoor stone relics. Due to the natural environment and various activities of animals and plants leading to serious damage, including rock painting surface damage, weathering denudation, and because of a variety of reasons resulting in dangerous rock blocks. Therefore, this paper takes Helankou rock painting as the research object, on the basis of the investigation of the rock painting area, analyzes and measures the basic microscopic and physical properties of the rock material, and obtains the density and porosity of the rock. Physical properties such as water absorption, content of elements and microscopic morphology of rock painting materials: through indirect tensile test of rock materials (Brazilian splitting method), uniaxial compression test, conventional triaxial compression test and direct shear test, The mechanical parameters and deformation and failure characteristics of rock in Helankou rock painting are obtained for the first time, and the stability analysis of typical dangerous rock mass near "donkey sheep map", "handprint map" and "Shipo rock painting group" is carried out. The conclusion of stability of dangerous rock mass is obtained. The results show that: (1) the density, porosity and water absorption of rock samples are high, the contents of O and Si elements are the highest, it is concluded that the main detritus of rock samples is quartz, and the weathering phenomenon of untreated rock samples is very obvious. The results show that the grain distribution on the rock surface is irregular, the structure is scattered, and the microcracks are more developed, while the core surface grain distribution is relatively regular, and the fracture development is relatively not obvious. The mechanical strength is also relatively high. (2) indirect tensile (Brazilian splitting), uniaxial compression, conventional triaxial compression and uniaxial direct shear tests for rock materials, The average tensile strength of rock samples is 5.6 MPA, the average uniaxial compressive strength is 190MPa, the Poisson's ratio is about 0.286, the average elastic modulus is 42.99GPa. the values of cohesion and internal friction angle are 40.66MPa and 48.220, respectively. The prediction of the strength of rock material by microcosmic characteristics is verified by the experiment. The triaxial compression stress-strain curves of rock samples are obtained by triaxial compression test. The curves can be divided into four stages: elastic deformation stage, plastic stage and failure stage, and residual strength stage. The correlation coefficient R2 of shear stress curve and vertical stress curve is 0.9861, which indicates that the linear relationship between the two stresses is close, that is, with the increase of axial compression, the shear failure load is assumed to increase linearly. The shear-displacement curve is also steeper. (3) the stability of the typical dangerous rock mass near the gully of Helankou rock painting, such as "handprint map", "donkey sheep map" and "Shipo rock painting group", is calculated. It is found that the three dangerous rock masses are in relatively safe condition except for the dangerous rock mass near Shipo rock painting group which is not clear enough. The research results of this paper can be used as guidance for the protection of Helankou rock paintings.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

【参考文献】