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禹海涛, 李婷婷, 陈志伟, 闫晓. 考虑破碎带节理分布特征的隧道开挖诱发近断层错动随机性分析[J]. 岩土工程学报, 2024, 46(4): 746-754. DOI: 10.11779/CJGE20221536
引用本文: 禹海涛, 李婷婷, 陈志伟, 闫晓. 考虑破碎带节理分布特征的隧道开挖诱发近断层错动随机性分析[J]. 岩土工程学报, 2024, 46(4): 746-754. DOI: 10.11779/CJGE20221536
YU Haitao, LI Tingting, CHEN Zhiwei, YAN Xiao. Stochastic analysis of fault dislocation induced by tunnel excavation considering distribution characteristics of joints in fracture zones[J]. Chinese Journal of Geotechnical Engineering, 2024, 46(4): 746-754. DOI: 10.11779/CJGE20221536
Citation: YU Haitao, LI Tingting, CHEN Zhiwei, YAN Xiao. Stochastic analysis of fault dislocation induced by tunnel excavation considering distribution characteristics of joints in fracture zones[J]. Chinese Journal of Geotechnical Engineering, 2024, 46(4): 746-754. DOI: 10.11779/CJGE20221536

考虑破碎带节理分布特征的隧道开挖诱发近断层错动随机性分析

Stochastic analysis of fault dislocation induced by tunnel excavation considering distribution characteristics of joints in fracture zones

  • 摘要: 隧道开挖往往会引起邻近断层错动,并进一步诱发岩爆、地震等灾害。然而,断层破碎带内部岩体物理力学特征复杂,不仅表现出非连续性、非线性和各向异性,还存在节理随机分布特征,隧道开挖诱发近断层错动机制仍不清晰。基于连续-离散耦合分析方法建立了含断层工程场地多尺度力学模型,采用基于离散单元法的人工合成岩体模型模拟断层破碎带,采用有限差分法描述断层上、下盘及内部隧道开挖影响下的宏观动力特征。开展了近断层隧道开挖多因素模拟,探究了断层岩体节理随机分布特征对近断层隧道开挖的影响规律。分析结果表明:破碎带内部节理随机性对隧道开挖诱发近断层错动影响显著;节理倾角均值越接近断层倾角,隧道开挖导致的近断层错动量越大;正交试验情况下,断层节理倾角方差对最终错动量均值大小影响较小;节理长度的均值和方差越大,断层破碎带越容易发生错动;节理密度越大,破碎带介质越破碎,断层带整体的强度和刚度越低,抵抗错动的能力也越弱。通过对比分析得出节理分布特征参数对断层错动量均值影响程度的排序分布:节理密度 > 节理倾角均值> 节理长度均值> 节理长度标准差 > 节理倾角标准差;且当显著性水平为0.05时,节理密度对断层错动量的影响达到显著水平(p < 0.05)。

     

    Abstract: Tunnel excavation often causes the dislocation of adjacent faults, and further induces rockbursts, earthquakes and other disasters. Due to the complex physical and mechanical characteristics of rock mass, the fault exhibits discontinuity, nonlinear and anisotropy and has the random distribution of joints, which makes the mechanism of adjacent fault dislocation induced by tunnel excavation still unclear. A multi-scale model is established based on the continuous-discrete coupling method. The synthetic rock mass model based on the discrete element method is used to simulate the fault damage zone, and the finite difference method is used to describe the macroscopic dynamic characteristics of the upper and lower walls. The influence laws of the random distribution characteristics of joints on the excavation simulation of a near-fault tunnel are explored. The results show that the randomness of joints in the fracture zone has a significant effect on fault dislocation. The fault dislocation increases with the mean dip angle of joints closer to that of fault. In the case of orthogonal tests, the variance of dip angle has small effects on the mean value of final dislocation. The increase of the mean and variance of joint length causes the fault prone to dislocation. The greater the joint density, the more broken the media in the fracture zone, the lower the overall strength and stiffness, and the weaker the resistance to dislocation. Through a comparative analysis, the influence degree of distribution characteristic parameters of joints on the mean value of fault dislocation is: density > mean value of dip angle > mean value of length > standard deviation of length > standard deviation of dip angle. When the significance level is 0.05, the influences of joint density on the momentum of fault dislocation reach a significant level (p < 0.05).

     

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