含水率对层状砂岩劈裂抗拉强度影响研究

发布时间：2018-01-29 09:03

本文关键词： 岩石力学层状砂岩层理弱面含水率劈裂抗拉强度微观形貌　出处：《岩石力学与工程学报》2017年11期 　论文类型：期刊论文

【摘要】：为了研究含水率对层状岩体劈裂抗拉强度的影响,特选取层理显著的砂岩为研究对象,考虑5种含水率,进行顺层理弱面的劈裂抗拉强度试验,结合岩样劈裂破坏面的微观形貌特征和能量参数变化规律进行综合分析。研究结果表明:(1)随着含水率的增加,层状砂岩的抗拉强度逐渐减小,总体呈现先陡后缓的降低趋势,在饱水度低于80%左右时,抗拉强度降低幅度明显较大,而后抗拉强度降低趋势逐渐趋于缓慢;(2)岩样劈裂破坏面的高度参数和纹理参数都随着饱水度的增加而逐渐增大,呈先陡后缓的增长趋势,岩样抗拉强度与劈裂面微观形貌参数存在较好的线性相关性;(3)随着含水率的增加,加载过程中岩样吸收的总能量、弹性应变能逐渐减小,呈现与抗拉强度类似变化趋势,弹性应变能占总能量的比值逐渐减小,耗散能占总能量的比值逐渐增大;(4)层理弱面既是层状岩体结构的薄弱面,也是水分吸收和运移的主要空间和通道,含水率增加,首先是影响岩样层理弱面力学性状和孔隙水的分布,改变岩样加载过程中的裂纹扩展规律,进而影响加载过程中的弹性应变能和耗散能的分配比例,从而导致岩样劈裂破坏面形态趋于复杂,抗拉强度降低,水对岩样抗拉强度的影响是一个从微观结构变化导致宏观力学特性劣化的过程。
[Abstract]:In order to study the effect of water content on the splitting tensile strength of layered rock mass, the sandstone with remarkable bedding is selected as the research object, and five kinds of water content are considered, and the splitting tensile strength test on the weak surface of the bedding is carried out. The results show that the tensile strength of layered sandstone decreases with the increase of water content. As a whole, the decrease trend of tensile strength is first steep and then slow. When the degree of saturation is less than 80%, the decrease of tensile strength is obviously larger, and then the trend of decrease of tensile strength tends to be slow. (2) the height parameters and texture parameters of the fracture surface of rock samples increase with the increase of saturation degree, showing a trend of first steepness and then slow growth. There is a good linear correlation between the tensile strength of rock samples and the micro-morphology parameters of split surface. 3) with the increase of moisture content, the total energy and elastic strain energy absorbed by rock samples decrease gradually, which is similar to the tensile strength, and the ratio of elastic strain energy to total energy decreases gradually. The ratio of dissipation energy to total energy increases gradually. The weak plane of bedding is not only the weak plane of stratified rock structure, but also the main space and passage for water absorption and migration. The increase of water content is the first factor affecting the mechanical properties and pore water distribution of stratified weak plane of rock samples. Changing the law of crack propagation in the loading process of rock samples, and then affecting the distribution ratio of elastic strain energy and dissipation energy in the loading process, resulting in the formation of fracture surface of rock samples tends to be complex, and the tensile strength decreases. The effect of water on the tensile strength of rock samples is a process of deterioration of macroscopic mechanical properties caused by the change of microstructure.
【作者单位】：三峡大学三峡库区地质灾害教育部重点实验室;
【基金】：湖北省自然科学基金重点项目(2015CFA140) 国家自然科学基金资助项目(51439003,51679127)~~
【分类号】：TU45
【正文快照】： 工程岩体赋存环境中一般都有水的存在[1],水对岩石的物理、力学特性影响效应明显,很多工程岩体的变形破坏都与水有关。岩石的抗拉强度远低于抗压强度,含水岩石在受载的时候经常发生抗拉破坏。因此,研究含水状态下岩石的抗拉力学特性具有重要的工程意义[2]。国内外学者对含水岩

【相似文献】