Interpretation of increased deformation rate in aquifer IV due to groundwater pumping in Shanghai
Bibliographic record
Abstract
Shanghai is a typical example of a region in China suffering from severe land subsidence. Previous investigations have shown that land subsidence is strongly related to groundwater pumping in both the temporal and spatial domains. A series of field investigations shows that the deformation rate of aquifer IV (AqIV) has increased, contributing significantly to the total subsidence in Shanghai. To predict the deformation behavior of AqIV in Shanghai due to groundwater pumping, four different models have been applied in this study: (i) a model based on groundwater flow theory, (ii) an elastic model based on Cauchy mechanics, (iii) a creep model incorporated into Cauchy mechanics, and (iv) a recently proposed land subsidence model by Budhu based on Cosserat mechanics. Based on a number of assumptions, Budhu’s concept was extended to consider the time-dependent behavior of groundwater potential in aquifers and the consolidation behavior of overburdened aquitards. The calculated results of AqIV’s deformation were compared with the field-measured data. The results show that when using groundwater flow theory and Cauchy mechanics, it is difficult to predict the increased deformation rate of the sandy layers in aquifers even when the creep behavior is incorporated into the calculation. However, Budhu’s method based on Cosserat mechanics can predict this increased deformation rate well. The predicted result indicates that increased deformation of aquifer IV is due to volumetric contraction caused by shear stress rather than the creep of aquifer sand. The phenomenon of deformation delay in aquifers can also be interpreted with the proposed model.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".