To investigate the mechanical response of a deep-buried circular tunnel under biaxial non-uniform stress conditions after damage,an elastic-plastic solution was established based on the unified strength theory,considering the damage effects of the deep surrounding rock.Utilizing the Dongmachang tunnel as a reference case,the influences of damage effects and medium principal stress on the stress and deformation of the surrounding rock were explored.Additionally,the extent of damage within deep soft surrounding rock at varied lateral pressure coefficients,dilation coefficients,and support forces was investigated.The results show that the post-peak damage effects in surrounding rock exacerbate tunnel squeezing deformation after excavating deep-buried circular tunnels under biaxial non-uniform stresses.The deformation calculation results considering damage effects are closer to the on-site measured results.The medium principal stress enhances the load-bearing capacity of the surrounding rock and restrains tunnel squeezing deformation.Disregarding medium principal stress may overestimate the deformation potential of the tunnel.The lateral pressure coefficient governs the shape and size of the damaged rock zone,suggesting that grouting reinforcement at critical deformation sites should be tailored based on the extent of damage at different locations in the surrounding rock.As the dilation coefficient increases,the degree of damage within surrounding rock expands,and the range of complete damage expands.Support forces play a crucial role in restraining post-peak damage in surrounding rock.Consequently,timely implementation of support measures to restrain and stabilize the surrounding rock's response is imperative in practical engineering applications.
关键词
二向不等压/损伤效应/深埋圆形隧道/统一强度理论
Key words
biaxial non-uniform stress/damage effects/deep-buried circular tunnel/unified strength theory
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基金项目
国家自然科学基金资助项目(52178402)
中国中铁股份有限公司科技研究开发计划项目(2021-重点-09)
中国中铁股份有限公司科技研究开发计划项目(2022-重点-10)
National Natural Science Foundation of China()
Science and Technology Research and Development Program of China Railway Group Limited(2021-Key-09)
Science and Technology Research and Development Program of China Railway Group Limited(2022-Key-10)
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