Undrained stability of pit-in-pit braced excavations under hydraulic uplift
Article
Article Title | Undrained stability of pit-in-pit braced excavations under hydraulic uplift |
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ERA Journal ID | 214415 |
Article Category | Article |
Authors | Lai, Fengwen (Author), Chen, Fuquan (Author), Liu, Songyu (Author), Keawsawasvong, Suraparb (Author) and Shiau, Jim (Author) |
Journal Title | Underground Space |
Journal Citation | 7 (6), pp. 1139-1155 |
Number of Pages | 17 |
Year | 2022 |
Publisher | KeAi Publishing Communications Ltd. |
Place of Publication | China |
ISSN | 2096-2754 |
2467-9674 | |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.undsp.2022.04.003 |
Web Address (URL) | https://www.sciencedirect.com/science/article/pii/S2467967422000605 |
Abstract | Pit-in-pit (PIP) excavations in an aquifer–aquitard system likely undergo catastrophic failures under the hydraulic uplift, the associated undrained stability problem, however, has not been well analyzed in the past. To this end, a hypothetical model of PIP braced excavation in typical soil layers of Shanghai, China is developed using the finite element limit analysis (FELA) tool. The FELA solutions of safety factors (FSs) against hydraulic uplift are verified with the results from the finite element analysis with strength reduction technique (SRFEA) and existing design approaches. Subsequently, FELA is employed to identify the triggering and failure mechanisms of PIP braced excavations subjected to hydraulic uplift. A series of parametric studies considering the various geometric configurations of the PIP excavation, undrained shear strengths of aquitard, and artesian pressures are carried out. The sensitivities of relevant design parameters are further assessed using a multivariate adaptive regression splines (MARS) model that is capable of accurately capturing the nonlinear relationships between a set of input variables and output variables in multi-dimensions. A MARS-based design equation used for predicting FS is finally presented using the artificial dataset from FELA for practical design uses. |
Keywords | Pit-in-pit excavation; Hydraulic uplift; Undrained stability; Finite element limit analysis; Multivariate adaptive regression splines |
ANZSRC Field of Research 2020 | 400502. Civil geotechnical engineering |
Byline Affiliations | Southeast University, China |
Fuzhou University, China | |
Thammasat University, Thailand | |
School of Civil Engineering and Surveying | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q78yw/undrained-stability-of-pit-in-pit-braced-excavations-under-hydraulic-uplift
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