Tunnel Lining Formwork Tilt for Air Bubble Removal
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Solution Overview
Problem
Existing methods for producing tunnel linings result in an uneven upper surface due to air bubbles causing craters, leading to increased material costs and complexity in maintaining shield tail seals, as the surface needs to be manually smoothed post-concrete hardening, which can deform the tubbing.
Innovation Solution
A method involving a tilting arrangement of the segment formwork to allow air bubbles to rise and escape before concrete solidification, eliminating the need for manual smoothing and ensuring a smoother surface, with the formwork being tilted into a compaction position where air bubbles are directed away from the upper surface, using a filling funnel and excess concrete to prevent air re-entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cover arrangement is opened to smooth the upper side of the tubbing by hand, then the surface smoothness is improved, but the tubbing deforms slightly in the edge area and bulging formations arise
Solution Approach 1:
The formwork is tilted into a compaction position before the concrete has hardened, allowing air bubbles to rise and escape to the opening before they can cause craters. This preliminary action prevents the need for manual smoothing after hardening, thereby avoiding deformation while ensuring surface smoothness.
Solution Approach 2:
The formwork is made tiltable, transitioning from a static horizontal position to a dynamic tilted compaction position. This allows the air bubbles to move freely under gravity toward the opening, enabling automatic air removal without manual intervention and preventing subsequent deformation.
2Manufacturing precision
If the cover arrangement is not completely closed after smoothing, then the upper side can be smoothed, but the upper side deforms slightly and bulging formations arise
Solution Approach 1:
The formwork is tilted into a compaction position before the concrete has hardened, allowing air bubbles to rise and escape to the opening before they can cause craters. This preliminary action prevents the need for manual smoothing after hardening, thereby avoiding deformation while ensuring surface smoothness.
Solution Approach 2:
The tilted formwork configuration enables air bubbles to automatically rise and escape to the opening through gravity-driven movement, without requiring manual smoothing operations or incomplete closing of the cover arrangement. The system self-corrects the air bubble problem through its geometric configuration.
3Manufacturing precision
If manual smoothing is performed after concrete hardening, then the upper side can be smoothed, but the process is expensive and time-consuming
Solution Approach 1:
The formwork is tilted into a compaction position before the concrete has hardened, allowing air bubbles to rise and escape to the opening before they can cause craters. This preliminary action prevents the need for manual smoothing after hardening, thereby avoiding deformation while ensuring surface smoothness.
Solution Approach 2:
The tilted formwork configuration enables air bubbles to automatically rise and escape to the opening through gravity-driven movement, without requiring manual smoothing operations or incomplete closing of the cover arrangement. The system self-corrects the air bubble problem through its geometric configuration.
4Manufacturing precision
If the formwork is tilted into a compaction position, then air bubbles rise and escape to the opening, but the concrete must be poured in a specific manner
Solution Approach 1:
The formwork is made tiltable, transitioning from a static horizontal position to a dynamic tilted compaction position. This allows the air bubbles to move freely under gravity toward the opening, enabling automatic air removal without manual intervention and preventing subsequent deformation.
Solution Approach 2:
The formwork inclination angle is changed from horizontal (0 degrees) to a tilted compaction position (greater than 0 degrees). This parameter change enables air bubbles to move under gravity toward the opening, facilitating automatic air removal while maintaining concrete pouring feasibility through controlled inclination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents crater formation on the tubbing's surface, reduces material costs by minimizing grease usage, and allows for more efficient tunnel construction with a smoother, less deformed upper surface, enabling easier removal of the formwork and improved pore patterns in the solidified tubbing.
Implementation Method 1
below the opening, on the underside of the lid arrangement, accumulating air bubbles rise along the underside to the opening
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method and to a plant for producing tubbing for a tunnel lining, wherein a tubbing shell (4) having a cover arrangement (12) which can be opened, has an underside and comprises an opening is filled with fresh concrete (24) and the tubbing is removed from the tubbing shell (4) after it has solidified. The fact that the tubbing shell (4) is tipped into a compression position at least before solidification, which compression position is selected in such a way that air bubbles (32) which collect below the opening on the underside of the cover arrangement (12) rise to the opening along the underside, achieves a situation where the upper side of the produced tubbing which later faces the tunnel outer side is smoother and/or has less deformations and/or can be produced less expensively than previously.