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Dewatering induced subsidence during excavation in a Shanghai soft deposit
- Source :
- Environmental Earth Sciences. 76
- Publication Year :
- 2017
- Publisher :
- Springer Science and Business Media LLC, 2017.
-
Abstract
- Foundation dewatering has become a major cause of land subsidence in Shanghai. The burial depth of foundations in relation to geotechnical construction works is less than 75 m, and the corresponding groundwater includes phreatic, low-pressure artesian, and the first confined aquifers. Based on the geological and hydrogeological conditions beneath Shanghai, methods of dewatering may be divided into three modes and further five patterns according to the insertion depth of the dewatering-retaining system. The most common dewatering mode aims to reduce the water pressure in the confined aquifer by setting the dewatering wells inside the pit, whilst the retaining walls are buried in the confined aquifer and partially cut off the confined aquifer layer. To predict the settlement due to foundation dewatering, numerical models are generally adopted, which are similar to those used to predict land subsidence induced by regional groundwater withdrawal; however, since foundation dewatering is conducted along with the setting of retaining walls and foundation pit excavation, which differs from regional groundwater withdrawal, interactions between the retaining wall-dewatering well, the dewatering-excavation, and dewatering-recharge are important factors affecting the analytical model. Since the grading of the shallow soil layers is different, stratified settlement characteristics of the shallow soil strata and seepage erosion, which results in additional deformation, need to be given particular consideration.
- Subjects :
- Global and Planetary Change
geography
geography.geographical_feature_category
Hydrogeology
Artesian aquifer
0211 other engineering and technologies
Soil Science
Geology
Aquifer
Subsidence
02 engineering and technology
010502 geochemistry & geophysics
Retaining wall
01 natural sciences
Pollution
Dewatering
Environmental Chemistry
Geotechnical engineering
Groundwater
Phreatic
021101 geological & geomatics engineering
0105 earth and related environmental sciences
Earth-Surface Processes
Water Science and Technology
Subjects
Details
- ISSN :
- 18666299 and 18666280
- Volume :
- 76
- Database :
- OpenAIRE
- Journal :
- Environmental Earth Sciences
- Accession number :
- edsair.doi...........827b99e26a4a5c3ebf1c3ab52a2233b7