Numerical analysis of subsurface deformation induced by groundwater level changes in the Bangkok aquifer system
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RESEARCH PAPER
Numerical analysis of subsurface deformation induced by groundwater level changes in the Bangkok aquifer system Krit Saowiang1 • Pham Huy Giao1,2 Received: 24 September 2019 / Accepted: 12 September 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Subsurface deformation due to long terms of groundwater drawdown from 1960 to 1997 and groundwater recovery from 1997 to 2016 in the upper part of the Bangkok multi-aquifer system and their possible effects on substructure stability were analyzed. The updated groundwater monitoring data show a linear recovery trend with a full recovery by 2031 in the study aquifer. Subsurface deformation was calculated using FEM transient coupled pore pressure/effective stress analysis by Abaqus. It was found that the groundwater drawdown from 1960 to 1997 caused a subsidence of 51, 62, and 76 cm, while the following groundwater recovery from 1997 to 2016 could pull back a rebound of 9.8, 9.7, and 5.3% at the three study sites, respectively. The effects of the change in pore pressure and undrained shear strength of the clay layers on the ultimate pile capacity were studied for cases of high-rise and low-rise buildings at a selected site. It was found that the groundwater drawdown from 1960 to 1997 could cause an increasing rate of ultimate pile capacity of about 1.0–1.5% per year, while the groundwater recovery from 1997 to 2031 can cause a similar reduction rate of ultimate pile capacity. Keywords Abaqus Bangkok land deformation FEM consolidation analysis Groundwater recovery Modified Cam-Clay model Substructure stability
1 Introduction Due to the rapid increase development of urban areas of Bangkok, many infrastructure projects of high-rise building, sky train, Mass Rapid Transit (MRT) line system, expressway, etc., have been conducted in the last 50 years. After a long period of land subsidence due to excessive groundwater extraction from 1960 to 1997 [6, 12, 13], groundwater level in the underlying aquifers have gradually recovered from 1997 to present as reported by Giao et al. [7]. The change of groundwater situation Bangkok and its vicinity areas creates significant problems of longterm deformation and substructures stability.
& Pham Huy Giao [email protected]; [email protected] Krit Saowiang [email protected] 1
Geotechnical and Earth Resources Engineering, Asian Institute of Technology (AIT), Pathum Thani, Thailand
2
Petro Vietnam University (PVU), Baria-Vung Tau, Thailand
A number of the researchers have investigated the land subsidence of Bangkok due to groundwater drawdown by numerical method. JICA [8] and Nutalaya et al. [11] studied the land subsidence by the 3D hydrologic model coupled with a to the 1-D consolidation model. Giao [5] developed a FEM program and revised in 2012 to analyze the land subsidence due to groundwater drawdown in the Bangkok area. Giao et al. [7] presented results of the 1DFEM consolidation analysis for the subsidence and rebound of the uppermost 25-
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