引水隧洞穿越大型断裂带围岩力学响应

发布时间：2018-10-12 17:01

【摘要】：针对引水隧洞地质条件复杂、岩性差异大的特征,建立仿真三维模型,采用Mohr-Coulomb弹塑性本构模型,以分段开挖方式,对比纯开挖、支护开挖围岩径向位移、应力响应差异,分析研究隧洞穿越大型断裂带过程中的围岩力学行为。结果表明,断裂带右侧初始自重应力明显偏低,附近石灰岩段存在应力集中现象,开挖后断裂带左侧洞顶径向位移明显大于右侧;纯开挖时,已开挖部分洞壁径向应力趋于零,掌子面前方约3倍洞径范围应力释放与应力集中现象突出,各分段掌子面附近出现径向位移极小值点;开挖支护时,已开挖部分洞壁径向应力维持在较高水平,处于三向压缩状态,掌子面前方应力集中现象减弱,在各分段开挖掌子面前方应力释放区内,径向应力极小值点和径向位移极大值点一一对应,间接反映支护时机对围岩力学响应的影响。研究成果可为引水隧洞施工提供指导。
[Abstract]:Aiming at the characteristics of complicated geological conditions and large difference in lithology of diversion tunnel, a three-dimensional simulation model is established, and Mohr-Coulomb elastoplastic constitutive model is adopted. Compared with pure excavation, the radial displacement and stress response of surrounding rock of supporting excavation are different by using Mohr-Coulomb elastoplastic constitutive model. The mechanical behavior of surrounding rock in the process of tunnel crossing large fault zone is analyzed and studied. The results show that the initial gravity stress of the right side of the fault zone is obviously low, the stress concentration phenomenon exists in the nearby limestone section, the radial displacement of the left hole top of the fault zone is obviously larger than that of the right side after excavation, and the radial stress of the excavated part of the tunnel wall tends to zero during pure excavation. The phenomenon of stress release and stress concentration in front of about 3 times diameter range of tunnel is prominent, radial displacement minimum point appears near each segment face, and radial stress of excavated part of tunnel wall is maintained at a higher level during excavation support. In the state of triaxial compression, the phenomenon of stress concentration in front of the face of the palm is weakened, and the radial stress minimum point and the radial displacement maximum point correspond to one by one in the stress release area in front of each section excavation face. Indirectly reflect the influence of supporting timing on the mechanical response of surrounding rock. The research results can provide guidance for the construction of diversion tunnel.
【作者单位】：成都理工大学地质灾害防治与地质环境保护国家重点实验室;
【基金】：国家自然科学基金项目(41272332)
【分类号】：TV554

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