Performance of Fully Grouted Piezometers under Transient Flow Conditions: Field Study and Numerical Results
Bibliographic record
Abstract
Abstract Piezometers can be installed in clay layers using the fully grouted method. This method is said to reduce installation costs and facilitate installation, especially for nested piezometers. The success of a fully grouted installation depends upon the ratio of grout and surrounding soil hydraulic conductivity and upon the grout physical stability. This article presents new results from field tests and numerical simulations regarding the performance of fully grouted piezometers under transient flow conditions. The field observations show that using low-permeability grout for piezometer installation provides precise pore water pressure (PWP) measurements. This confirms previous findings on the fully grouted installation technique. Field observations for a very high-permeability grout that could be more than 1,100 times more permeable than the soil result in PWPs that totally differ from the PWP obtained with a low-permeability grout. Using three scenarios involving transient flow, the numerical results show that hydraulic conductivity ratios between 0.001 and 10 provide an accurate pore pressure response without a significant time lag for soils with a very low permeability (K ≤ 2 × 10−9 m/s). For most practical applications, a hydraulic conductivity ratio of 100 is the upper limit to obtain acceptable pore pressure measurements for these soils. A large hydraulic conductivity ratio may cause a hydraulic short circuit between the fully grouted piezometer and the upper aquifer. For a borehole diameter of 100 mm, the numerical results demonstrate that grout stiffness has no significant impact on the performance of fully grouted piezometers. However, grout stiffness is important for the long-term performance of the fully grouted piezometer. This article also introduces preliminary results regarding a testing program on grout properties. These results confirm pervious findings by others that the preparation of low-permeability grout is not trivial and that grout initial viscosity controls its physical stability and hydraulic conductivity.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".