3D FE back analysis of a staged SCL tunnel in London Clay using BRICK soil constitutive model
3D FE back analysis of a staged SCL tunnel in London Clay using BRICK soil constitutive model
Two sets of BRICK soil model parameters have been used in undrained 3D FE analyses of a greenfield SCL tunnel in over-consolidated London Clay, constructed during the London Kings Cross station redevelopment. Each parameter set represent most probable and characteristic predicted movements fitted against deep excavation back analyses, historical tunnelling and laboratory tests. The as-built sequential construction sequence was explicitly modelled, consequently no prior assumptions of volume loss and stress relaxation are required. Movement predictions compare well against measured ground settlement. Derived volume losses match conventional the empirical gaussian curve-fit result. Most probable and characteristic BRICK soil parameters are shown to respectively reproduce average and upper bound predictions as compared against measured ground movements. A limit on allowable negative pore water pressure in the undrained models is presented as a useful tool for real-time ground movement back analysis to identify poorer soil conditions and anomalous construction quality. The paper concludes by presenting a strategy to use FE predictions with the observational method during future SCL tunnelling works.
Pishun Tantivangphaisal; A. Pillai; Duncan Nicholson
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
10. Tunnelling and mining applications
https://doi.org/10.53243/NUMGE2023-219
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