循环荷载下干燥与饱和砂岩力学特性及能量演化

发布时间：2019-07-29 20:43

【摘要】：对取自陕北榆横矿区小纪汗煤矿顶板砂岩的干燥及饱和试件进行单轴循环加、卸载试验,分析了干燥与饱和状态下岩石的强度和变形特征以及岩石破坏过程中的能量演化与能量分配情况。结果表明:(1)循环加、卸载导致干燥试件的峰值强度较单轴压缩时下降19.47%;(2)饱水对砂岩的强度和变形均有影响,饱和试件的平均峰值强度比干燥试件低39.55%,同时饱和试件具有更加明显的压密阶段;(3)循环加、卸载下砂岩的加载和卸载弹性模量均呈现增大趋势,但饱和试件的弹性模量低于干燥试件;(4)通过峰值强度归一化处理后发现,在应力加载的不同阶段,饱和试件的弹性应变能Ue和耗散能Ud均低于干燥试件;(5)加载过程中,饱和试件弹性应变能Ue的占比高于干燥试件,该比例随着加载过程逐渐下降并在破坏前与干燥试件的Ue的占比达到近似水平。
[Abstract]:Uniaxial cyclic loading and unloading tests were carried out on drying and saturated specimens taken from roof sandstone of Xiaoji Khan Coal Mine in Yuheng Mining area, northern Shaanxi. The strength and deformation characteristics of rock under drying and saturation conditions, as well as energy evolution and energy distribution during rock failure were analyzed. The results show that: (1) the peak strength of dry specimens is 19.47% lower than that of uniaxial compression, (2) saturated water has an effect on the strength and deformation of sandstone, the average peak strength of saturated specimens is 39.55% lower than that of dry specimens, and the saturated specimens have more obvious compaction stage. (3) the elastic modulus of sandstone under cyclic loading and unloading tends to increase, but the elastic modulus of saturated specimen is lower than that of dry specimen. (4) after peak strength normalization treatment, it is found that the elastic strain energy Ue and dissipation energy Ud of saturated specimen are lower than those of dry specimen at different stages of stress loading. (5) in the loading process, the proportion of elastic strain energy Ue of saturated specimen is higher than that of dry specimen, and the proportion of elastic strain energy Ue of saturated specimen decreases gradually with the loading process and reaches an approximate level with that of dry specimen before failure.
【作者单位】：东北大学资源与土木工程学院;贵州大学贵州省非金属矿产资源综合利用重点实验室;贵州大学矿业学院;
【基金】：国家重点基础研究发展计划项目(No.2013CB227902) 贵州省科技计划项目(黔科合LH字[2016]7465号) 国家自然科学基金项目(No.51574059)~~
【分类号】：TD313

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