黄昌富, 张帅龙, 高永涛, 吴顺川, 周喻, 孙浩, 王文强, 卢庆钊. 三轴应力下颗粒流失对断层破碎带凝灰岩渗流特征的影响[J]. 工程科学学报, 2022, 44(7): 1134-1146. DOI: 10.13374/j.issn2095-9389.2021.11.22.001
引用本文: 黄昌富, 张帅龙, 高永涛, 吴顺川, 周喻, 孙浩, 王文强, 卢庆钊. 三轴应力下颗粒流失对断层破碎带凝灰岩渗流特征的影响[J]. 工程科学学报, 2022, 44(7): 1134-1146. DOI: 10.13374/j.issn2095-9389.2021.11.22.001
HUANG Chang-fu, ZHANG Shuai-long, GAO Yong-tao, WU Shun-chuan, ZHOU Yu, SUN Hao, WANG Wen-qiang, LU Qing-zhao. Influence of particle loss on the seepage characteristics of tuff in the fault fracture zone under triaxial stress[J]. Chinese Journal of Engineering, 2022, 44(7): 1134-1146. DOI: 10.13374/j.issn2095-9389.2021.11.22.001
Citation: HUANG Chang-fu, ZHANG Shuai-long, GAO Yong-tao, WU Shun-chuan, ZHOU Yu, SUN Hao, WANG Wen-qiang, LU Qing-zhao. Influence of particle loss on the seepage characteristics of tuff in the fault fracture zone under triaxial stress[J]. Chinese Journal of Engineering, 2022, 44(7): 1134-1146. DOI: 10.13374/j.issn2095-9389.2021.11.22.001

三轴应力下颗粒流失对断层破碎带凝灰岩渗流特征的影响

Influence of particle loss on the seepage characteristics of tuff in the fault fracture zone under triaxial stress

  • 摘要: 地下工程施工过程中,处于三向应力状态的断层破碎带凝灰岩在流固耦合作用下发生颗粒流失,继而诱发断层带破碎岩石结构失稳,最终导致断层突水灾害发生。基于此,开展现场断层取样,利用破碎岩石三轴渗透试验系统,研究三轴荷载下不同粒径级配试样颗粒流失规律,进而分析颗粒流失对孔隙结构与渗流流速时变演化规律的影响。研究结果表明:(1)不同三轴应力下,破碎凝灰岩颗粒流失质量与时间满足指数型函数关系,两者间相关系数不低于94%。颗粒流失质量与轴压和围压成反比,且轴向位移越大,颗粒流失质量随围压减小的幅度越小;(2)渗透过程中0~60 s间的孔隙率增长较快,孔隙结构的渗流演变过程与粒径级配有关,随着n (Talbot幂指数) 值的增大,孔隙率整体增大,n值相同时,孔隙率随轴向位移与围压的增大而减小,且孔隙率量级为0.33~0.52;(3)由于试样内部颗粒规律性流失,破碎凝灰岩渗流流速时变演化过程可划分为“平稳渗流、渗流流速突增和近似管流”三个阶段,围压为0.8 MPa时各阶段流速整体大于围压为1.4 MPa时对应阶段的流速。平稳渗流阶段历时短,流速低,其发生次数随n值增加而减少;渗流流速突增阶段流速猛增达到峰值;近似管流阶段保持较高流速,虽然偶尔产生波动,但整体相对平稳。研究成果可为断层突水灾害演化规律研究提供理论依据。

     

    Abstract: In the process of underground engineering construction, tuff in the fault fracture zone under a three-dimensional stress state loses particles under the action of fluid–solid coupling, causing the structural instability of the fault fracture rock. Finally, fault water inrush disaster occurs. Based on this, the field fault sampling has been conducted, and the broken rock triaxial seepage test system has been used to investigate the phenomenon of particle loss in samples with various particle sizes under triaxial load, as well as the effect of particle loss on pore structure and the time-varying evolution of seepage velocity. The following are the results: (1) The quality and time of the particle loss of broken tuff satisfy the exponential nonlinear relationship under different levels of triaxial stress, with a correlation coefficient of not less than 94%. Particle loss quality is inversely related to axial pressure and confining pressure, indicating that the higher the axial displacement, the smaller the decrease in particle loss mass with confining pressure. (2) The porosity increases rapidly between 0 and 60 s during the infiltration process. The seepage evolution process of the pore structure is related to the particle size gradation; that is, the overall porosity increases as the value of n (Talbot power exponent) increases. In the case of the same value of n, the porosity, which ranges from 0.33 to 0.52, decreases as the axial displacement and confining pressure increase. (3) Owing to the regular loss of particles in the sample, the time-varying evolution process of the seepage velocity of fractured tuff can be divided into three stages: stable seepage, sudden increase of seepage velocity, and approximate pipe flow. When the confining pressure is 0.8 MPa, each stage’s flow velocity is higher than that of the corresponding stage when the confining pressure is 1.4 MPa. The stable seepage stage has a short duration and low flow rate, and its occurrence times decrease as the n value increases. In the stage of seepage velocity surge, velocity surges to a peak value. The approximate pipe flow stage maintains a relatively stable and high flow velocity despite occasional fluctuations. The research results can offer a theoretical basis for studying the evolution law of fault water inrush disaster.

     

/

返回文章
返回