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A platform for research: civil engineering, architecture and urbanism
Probabilistic evaluation for excavation-induced longitudinal responses of existing shield tunnel in spatially random soils
Abstract The inherent spatial variability of soil properties has a non-negligible effect on the geo-structures system. The quantitative evaluation on the uncertainty of the geo-structure system and its influence on the longitudinal responses of a shield tunnel induced by the adjacent excavation are seldom investigated in the past. This work aims to perform the probabilistic evaluations on the excavation-induced tunnel performance using the proposed probabilistic framework. An improved Timoshenko beam-based soil-tunnel interaction model and its finite element solutions incorporating variability of ground stiffness are developed as the deterministic model in the probabilistic framework. A lognormal random field discretized by Karhunen-Loève expansion method is adopted to characterize the spatial variability of subgrade reaction coefficient. The sparse polynomial chaos expansion (SPCE) method is combined with the global sensitivity analysis (GSA) for establishment of an analytical metamodel with a reduced dimension of input variables. Subsequently, with the aid of Monte Carlo simulations, the probabilistic analysis for the tunnel performance is implemented using the SPCE metamodel to reduce the computational effort. The results show that the spatial variability of ground stiffness plays an important role in the longitudinal performance of the shield tunnel suffering from an adjacent excavation. As the spatial soil variability strengthens, the failure probability of the shield tunnel increases obviously. The maximal displacement and minimum curvature radius of the shield tunnel seem to be the robust indicators for assessing the tunnel performance due to the conservative evaluations from that compared with joint deformations.
Probabilistic evaluation for excavation-induced longitudinal responses of existing shield tunnel in spatially random soils
Abstract The inherent spatial variability of soil properties has a non-negligible effect on the geo-structures system. The quantitative evaluation on the uncertainty of the geo-structure system and its influence on the longitudinal responses of a shield tunnel induced by the adjacent excavation are seldom investigated in the past. This work aims to perform the probabilistic evaluations on the excavation-induced tunnel performance using the proposed probabilistic framework. An improved Timoshenko beam-based soil-tunnel interaction model and its finite element solutions incorporating variability of ground stiffness are developed as the deterministic model in the probabilistic framework. A lognormal random field discretized by Karhunen-Loève expansion method is adopted to characterize the spatial variability of subgrade reaction coefficient. The sparse polynomial chaos expansion (SPCE) method is combined with the global sensitivity analysis (GSA) for establishment of an analytical metamodel with a reduced dimension of input variables. Subsequently, with the aid of Monte Carlo simulations, the probabilistic analysis for the tunnel performance is implemented using the SPCE metamodel to reduce the computational effort. The results show that the spatial variability of ground stiffness plays an important role in the longitudinal performance of the shield tunnel suffering from an adjacent excavation. As the spatial soil variability strengthens, the failure probability of the shield tunnel increases obviously. The maximal displacement and minimum curvature radius of the shield tunnel seem to be the robust indicators for assessing the tunnel performance due to the conservative evaluations from that compared with joint deformations.
Probabilistic evaluation for excavation-induced longitudinal responses of existing shield tunnel in spatially random soils
Wang, Zuxian (author) / Shi, Chenghua (author) / Chen, Haiyong (author) / Lei, Mingfeng (author)
2024-01-19
Article (Journal)
Electronic Resource
English
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