中间主应力对砂岩扩容及强度特性影响
发布时间：2018-11-10 23:13
【摘要】：基于自主研发的"多功能真三轴流固耦合试验系统",进行了真三轴应力(σ1㧐σ2㧐σ3)条件下,保持体应力不变、改变中主应力系数的砂岩强度试验,探讨了不同中主应力系数条件下砂岩的变形、强度及剪切破坏特性。试验结果表明:在真三轴应力条件下,扩容起点随中主应力系数b的增大而呈递减趋势。应力加载过程中扩容存在明显的阶段性:随最大主应力的增加,稳定压缩段,体应变近似呈线性递增趋势;加速扩容段,体应变近似呈二次函数增大,且应变速率呈线性增大。保持体应力不变条件下,砂岩峰值强度随中主应力系数b的增大而逐渐降低,符合修正Lade准则。试验应力条件下,岩样主要发生双斜面对称剪切破坏,剪切破坏面倾角随b的增加呈线性增大。
[Abstract]:Based on the "multifunctional true triaxial fluid-solid coupling test system", a sandstone strength test was carried out under the condition of true triaxial stress (蟽 1? 蟽 2? 蟽 3), which kept the body stress unchanged and changed the principal stress coefficient. The deformation, strength and shear failure characteristics of sandstone under different medium principal stress coefficients are discussed. The experimental results show that under the condition of true triaxial stress, the starting point of expansion decreases with the increase of the principal stress coefficient b. During the stress loading, there are obvious phases: with the increase of the maximum principal stress, the volume strain increases linearly in the steady compression section, and in the accelerated expansion section, the volume strain approximate increases as a quadratic function and the strain rate increases linearly. The peak strength of sandstone decreases with the increase of the mid-principal stress coefficient b under the condition of keeping the body stress constant, which is in line with the modified Lade criterion. Under the experimental stress condition, the double inclined plane symmetrical shear failure occurs mainly, and the slope of the shear failure plane increases linearly with the increase of b.
【作者单位】： 重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学资源及环境科学学院;重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室;
【基金】：国家自然科学基金资助项目(51434003,51374256) 2016重庆市科研创新资助项目(CYS16012)
【分类号】：TD311
本文编号：2323839
[Abstract]:Based on the "multifunctional true triaxial fluid-solid coupling test system", a sandstone strength test was carried out under the condition of true triaxial stress (蟽 1? 蟽 2? 蟽 3), which kept the body stress unchanged and changed the principal stress coefficient. The deformation, strength and shear failure characteristics of sandstone under different medium principal stress coefficients are discussed. The experimental results show that under the condition of true triaxial stress, the starting point of expansion decreases with the increase of the principal stress coefficient b. During the stress loading, there are obvious phases: with the increase of the maximum principal stress, the volume strain increases linearly in the steady compression section, and in the accelerated expansion section, the volume strain approximate increases as a quadratic function and the strain rate increases linearly. The peak strength of sandstone decreases with the increase of the mid-principal stress coefficient b under the condition of keeping the body stress constant, which is in line with the modified Lade criterion. Under the experimental stress condition, the double inclined plane symmetrical shear failure occurs mainly, and the slope of the shear failure plane increases linearly with the increase of b.
【作者单位】： 重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学资源及环境科学学院;重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室;
【基金】：国家自然科学基金资助项目(51434003,51374256) 2016重庆市科研创新资助项目(CYS16012)
【分类号】：TD311
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