Use of Grouting to Reduce Deformations of an Existing Tunnel Underpassed by Another Tunnel
Bibliographic record
Abstract
The Greater Cairo metre and El-Azhar road tunnels, the major project of underground structures in Cairo city, Egypt, have been constructed. During the construction of the Greater Metro Line 2 (Shubra El-kheima- Mubarak) and El-Azhar road tunnels, which are installed by the tunneling boring machine (TBM), Geotechnical challenges are expected to occur related to soil stability around the tunnels. One of these problems arises when parts of the metro and the road tunnels cross under an existing sewage tunnel during the construction. To control the potential problem, the National Authority for Tunnels (NAT) has applied grouting to the soil around the sewage, the metro and the road tunnels. In the present study, one of these problems is highlighted and a model is proposed to provide a prediction of the soil structure interaction using a 3-D model of the multi-crossing tunnel incorporating the effect of grouting. The cement-bentonite grouting is considered in this study. The objective of this study is to evaluate the usefulness of permeation grouting in reducing deformation around the sewage tunnel when the metro and the road tunnels pass underneath it at different crossing zones. To assess and understand effect of changing the soil stiffness by grouting on the behavior of the two tunnels, a parametric study has been performed. The study is conducted using a finite element method that models the three-dimensional behavior under both the effects of the tunnel crossings and effects of the grouting. A nonlinear stress-strain constitutive model is adopted to represent the soil surrounding the tunnel and a linear constitutive model is employed to represent the sewage tunnel liner. The effects are expressed in terms of the settlement and radial deformation of the sewage tunnel as the metro or the road tunnels pass underneath it for the cases with and without grouting. The 3-D model of predicting the behavior of the tunnel system under multi-crossing tunnels and grouting effect is described and the predictions are compared with the field measurements. The comparison reveals a good agreement between the computed and observed values.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".