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胡波, 杨圣奇, 徐鹏, 田文岭. 单裂隙砂岩蠕变模型参数时间尺度效应及颗粒流数值模拟研究[J]. 岩土工程学报, 2019, 41(5): 864-873. DOI: 10.11779/CJGE201905009
引用本文: 胡波, 杨圣奇, 徐鹏, 田文岭. 单裂隙砂岩蠕变模型参数时间尺度效应及颗粒流数值模拟研究[J]. 岩土工程学报, 2019, 41(5): 864-873. DOI: 10.11779/CJGE201905009
HU Bo, YANG Sheng-qi, XU Peng, TIAN Wen-ling. Time-scale effect of the creep model parameters and particle flow simulation of sandstone with a single crack[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(5): 864-873. DOI: 10.11779/CJGE201905009
Citation: HU Bo, YANG Sheng-qi, XU Peng, TIAN Wen-ling. Time-scale effect of the creep model parameters and particle flow simulation of sandstone with a single crack[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(5): 864-873. DOI: 10.11779/CJGE201905009

单裂隙砂岩蠕变模型参数时间尺度效应及颗粒流数值模拟研究

Time-scale effect of the creep model parameters and particle flow simulation of sandstone with a single crack

  • 摘要: 深部高应力环境下硬岩的蠕变变形不可忽略,尤其是裂隙岩体的蠕变变形。为研究含裂隙硬岩的长期蠕变变形行为及蠕变模型,采用高速水射流技术在红砂岩试样中预制了一条贯穿的α=45°单裂隙。确定了该裂隙岩石在围压30 MPa下的三轴压缩强度,采用单级加载方式对试样进行长期压缩蠕变试验,蠕变应力水平约为峰值偏应力的80%。试验结果表明:经历539 h(约22 d)的含45°单裂隙红砂岩只出现衰减和稳态蠕变变形,未发生加速蠕变破坏。为描述裂隙岩石的蠕变变形,在Burgers模型基础上基于有效应力原理建立了考虑损伤的蠕变模型。通过最小二乘法得到的蠕变模型参数显示出显著的时间效应,据此提出了考虑时间尺度的损伤蠕变模型,该模型可以描述裂隙岩石在不同时间尺度下的蠕变变形。最后,采用颗粒流程序PFC2D对试样的三轴压缩及蠕变进行了数值模拟,数值计算结果与试验结果吻合程度较高。研究工作为进一步研究裂隙硬岩的蠕变变形和模型提供了一定的参考价值。

     

    Abstract: The creep deformation behaviors of the hard rocks in deep high-stress environment, especially for the fractured hard rocks, cannot be neglected. To investigate the long-term creep deformation behaviors and the creep model for the fractured hard rock, the rocks with a single crack (α=45°) are obtained using the high speed water jet technology. The peak deviatoric stress (σp) of the fractured rock under a confinement of 30 MPa is obtained before single-step creep test. The applied creep deviatoric stress is approximately 80% of σp and the creep time is 539 h. The experimental results show that the fractured rock exhibits the primary and secondary creep deformations without the tertiary creep deformation and creep failure. To characterize the creep deformation behaviors of the fractured sandstone, a damage creep model based on the Burgers model and the effective stress principle is established. The parameters of the damage creep model determined by the least squares method show distinct time-scale effect. Therefore, a damage creep model considering time-scale effect is proposed to describe the creep deformation behaviors of the fractured hard rock under different time-scales. In contrast, the proposed model agrees well with the test data. Finally, the triaxial compressive tests and creep experiments are simulated using the particle flow code (PFC2D). The numerical results agree well with the experimental ones. The research work may provide references for further investigations on the creep deformation behaviors and models for the fractured hard rock.

     

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