| 王俊光*,杨鹏锦,梁冰,金峤.基于颗粒流程序的不同加卸载条件下泥岩蠕变破裂规律研究[J].实验力学,2019,34(5):873~882 |
| 基于颗粒流程序的不同加卸载条件下泥岩蠕变破裂规律研究 |
| Study on the creep fracture laws of mudstone under different loading and unloading conditions based on particle flow code |
| 投稿时间：2018-09-21 修订日期：2018-10-23 |
| DOI：10.7520/1001-4888-18-214 |
| 中文关键词: 岩石力学 颗粒流程序 NVPB体 加卸载速率 蠕变破裂 |
| 英文关键词:rock mechanics particle flow code NVPB loading and unloading rate creep fracture |
| 基金项目:国家重点研发计划项目(2016YFC0600704)资助，国家自然科学基金(51404130)资助，辽宁省自然科学基金(20180550708)资助 |
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| 中文摘要: |
| 为研究平顶山12矿泥岩在不同加卸载围压速率下的蠕变破裂规律，在Bugers蠕变模型的基础上引入非线性黏塑性体(NVPB)串联构成Bugers-NVPB模型，基于颗粒流理论建立颗粒间力与位移的数值积分方案，二次开发出适用于二维颗粒流程序(PFC2D)且具有加速蠕变特性的黏弹塑性蠕变模型。建立PFC2D模型，并进行单轴压缩和三轴分级加载蠕变的模拟，通过与室内试验对比，验证了Bugers-NVPB模型对于蠕变试验的可行性。在此基础上，进行单轴压缩和不同加卸载围压速率下蠕变试验，分析了不同条件下试样的破裂形态、微裂纹数量和破裂机制。结果表明：在加卸载围压条件下，泥岩蠕变破裂形态比单轴压缩条件下更为复杂，且微裂纹总数更多；随着加卸载速率的增加，泥岩蠕变破裂形式由以剪切破坏为主，向张拉破坏为主过渡，微裂纹发育的局部化效应更加显著，微裂纹总数有所减少；在蠕变破裂阶段，试样均产生大量的张拉裂纹，且随着加卸载速率的减少，试件中较少的剪切裂纹对宏观破裂形态的影响愈加显著。 |
| 英文摘要: |
| In order to study the creep fracture laws of mudstone in Pingdingshan 12 mine under different loading and unloading conditions, the Bugers-NVPB model is developed by combining the Bugers creep model and the nonlinear viscoplastic body (NVPB). The numerical integration scheme of force and displacement between particles is established based on the particle flow theory. New two-dimensional Particle Flow Code (PFC2D) is obtained and the viscoelastic plastic creep model with the accelerated creep characteristics is further developed. In this work, the PFC2D model is established and subjected to uniaxial compression and three axis loading creep numerical simulation, and the feasibility of Bugers-NVPB model for creep test is verified by comparing with the laboratory tests. Moreover, uniaxial compression and creep tests under different loading and unloading confining pressure rates are carried out, and the fracture morphology, the number of microcracks and the fracture mechanism of samples under different conditions are analyzed. The results show that under the loading and unloading confining pressure condition, the fracture morphology of the specimen is much more complicated and the total number of microcracks is more than that under uniaxial compression. With the increase of loading and unloading rate, the specimen's fracture mode can transfer from the shear failure to the tensile failure, the localization effect of microcrack development becomes significant, and the total number of microcracks is reduced. In the creep fracture stage, a large number of tensile cracks are produced in the specimens, and with the decrease of loading and unloading rate, less shear cracks in the specimens have more significant impact on the macroscopic fracture morphology. |
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