A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Land subsidence in Shanghai (P.R. of China)
Abstract This study has been carried out under an International Cooperation Agreement between the People's Republic of China and Belgium. The final aim of the work is the detailed analysis of the geology, hydrogeology and engineering geology in the central area of Shanghai with an accurate simulation by a mathematical model of the subsidence occurring in this town and caused by groundwater withdrawals. The detailed study of the Quaternary layers in the upper portion of 70 meters has revealed a complex geometry of the different units composed of clay, loam, silt and sand. The features of the deposits have shown variation of the sedimentation process from estuarine to fluviatile conditions as a function of sudden river avulsions and tidal changes. Synthesis and compilation of all the hydrogeological and geotechnical tests madein situ on samples habe been completed. Many complementary tests (pumping tests, well-logging, pressuremeter tests, high and low pressure oedometer tests) have given the data needed by the mathematical model. On the basis of the results, hydrodynamic and geomechanical parameters of all the geological units have been determined. Data relative to withdrawal or recharge of water in the zone have been introduced in the model. Compaction and subsidence measurements in different places allow the calibration of the model. The Finite Element Method has been chosen using the LAGAMINE code developed at the University of Liege. This method allows to the use or very accurate spatial separation taking into account heterogeneities and facies variations of the layers. The simulation has comprised a 3D flow model giving as results the values and spatial distribution of the water pressures at each time step. Then, a coupled non-linear flow-compaction model has computed the subsidence as a function of time, taking the pressure variations in the aquifers as stress data. After the calibration procedure, simulations have been computed with «neutral» conditions (recharge ≥ pumping) and with “intensive pumping conditions” (pumping=1.$ 3^{*} $ recharge). The computed additional compactions between 1989 and 2000 in the last conditions are from 1.4 to 7.9 cm. The more sensitive zones have been located and the pumping effect on the subsidence rate has been quantified.
Land subsidence in Shanghai (P.R. of China)
Abstract This study has been carried out under an International Cooperation Agreement between the People's Republic of China and Belgium. The final aim of the work is the detailed analysis of the geology, hydrogeology and engineering geology in the central area of Shanghai with an accurate simulation by a mathematical model of the subsidence occurring in this town and caused by groundwater withdrawals. The detailed study of the Quaternary layers in the upper portion of 70 meters has revealed a complex geometry of the different units composed of clay, loam, silt and sand. The features of the deposits have shown variation of the sedimentation process from estuarine to fluviatile conditions as a function of sudden river avulsions and tidal changes. Synthesis and compilation of all the hydrogeological and geotechnical tests madein situ on samples habe been completed. Many complementary tests (pumping tests, well-logging, pressuremeter tests, high and low pressure oedometer tests) have given the data needed by the mathematical model. On the basis of the results, hydrodynamic and geomechanical parameters of all the geological units have been determined. Data relative to withdrawal or recharge of water in the zone have been introduced in the model. Compaction and subsidence measurements in different places allow the calibration of the model. The Finite Element Method has been chosen using the LAGAMINE code developed at the University of Liege. This method allows to the use or very accurate spatial separation taking into account heterogeneities and facies variations of the layers. The simulation has comprised a 3D flow model giving as results the values and spatial distribution of the water pressures at each time step. Then, a coupled non-linear flow-compaction model has computed the subsidence as a function of time, taking the pressure variations in the aquifers as stress data. After the calibration procedure, simulations have been computed with «neutral» conditions (recharge ≥ pumping) and with “intensive pumping conditions” (pumping=1.$ 3^{*} $ recharge). The computed additional compactions between 1989 and 2000 in the last conditions are from 1.4 to 7.9 cm. The more sensitive zones have been located and the pumping effect on the subsidence rate has been quantified.
Land subsidence in Shanghai (P.R. of China)
Monjoie, A. (author) / Paepe, R. (author) / He Yuan, SU (author)
1992
Article (Journal)
Electronic Resource
English
BKL:
56.00$jBauwesen: Allgemeines
/
38.58
Geomechanik
/
38.58$jGeomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
56.00
Bauwesen: Allgemeines
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB18
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