Slab Track Installation in Twin Tube Tunnels

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Solution Overview

Problem

The installation of slab tracks in tunnels poses challenges due to limited space and the need for precise levelling, alignment, and drainage, which are more demanding than traditional tracks, and existing methods are inefficient and costly.

Innovation Solution

A method involving a series of optimized phases for slab track installation using adapted mini-trains that move along an auxiliary side track, including formation of construction sections, design and construction of railway yards, assembly of auxiliary tracks, stocking of sleepers, construction of the foundation base, assembly of the slab track, transitions, and provision of long bars and welding, ensuring precise execution and reduced interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional construction methods are used for slab track installation in tunnels, then the construction process can proceed with conventional equipment, but the limited space in tunnels reduces productivity and increases complexity of operations

Engineering Contradiction:
Improveinstallation efficiencyVSAvoidconstruction complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The construction process is divided into sequential phases (phase 1, phase 2, phase 3) with each phase having specific tasks and equipment requirements. The tunnel construction is segmented into sections that can be worked on independently, allowing for systematic progression and improved management of limited space constraints.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic adaptation of equipment and methods based on the construction phase. Different equipment configurations are used in different phases (e.g., formwork removal in phase 1, slab construction in phase 2). The construction methodology dynamically adjusts to the specific requirements of each tunnel section and phase.

Inventive Principle:
Principle #15Dynamics

2Strength

If slab tracks are installed with embedded rails in concrete slabs, then load distribution is improved and stress is reduced, but the manufacturing precision requirements increase significantly

Engineering Contradiction:
Improveload distributionVSAvoidlevelling and alignment precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent implements preliminary preparation of the concrete slab with pre-formed channels and embedding locations before rail installation. The slab is constructed with precise geometric parameters and surface finish in advance, ensuring that when rails are embedded, the required precision is already achieved. This preliminary action includes formwork setup, concrete pouring, and initial curing under controlled conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical rail fastening systems with embedded rails that are integrated into the concrete slab structure. This substitution eliminates the need for separate fastening components and reduces the number of mechanical adjustment operations required, thereby maintaining precision while simplifying the overall system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If slab tracks are used instead of traditional ballast tracks, then maintenance requirements are reduced and operating availability increases, but the initial construction cost is higher

Engineering Contradiction:
Improveoperating availabilityVSAvoidconstruction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple functions into the concrete slab structure itself. The slab serves as both the foundation and the track support, eliminating the need for separate ballast layers and fastening systems. This merging reduces the number of components that require maintenance while consolidating construction activities, thereby improving reliability without excessive cost increase.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical and chemical parameters of the concrete slab to optimize performance. This includes controlling concrete composition, curing conditions, and surface properties to achieve the required strength, durability, and precision. By optimizing these parameters, the long-term reliability is enhanced while construction costs are managed through efficient material usage.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If precise levelling and alignment are required for slab tracks, then track stability is improved, but the construction time and complexity increase

Engineering Contradiction:
Improvetrack stabilityVSAvoidconstruction time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent implements preliminary setting of the concrete slab geometry and surface finish before rail installation. Formwork is precisely positioned and secured to ensure the required levelling and alignment are achieved during concrete pouring. This preliminary action eliminates the need for time-consuming post-pouring adjustments and ensures track stability is built into the structure from the beginning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The concrete slab construction process is designed to be self-leveling and self-aligning through proper formwork setup and concrete placement techniques. The system uses its own weight and fluidity during pouring to achieve uniform distribution and precise geometry, reducing the need for external intervention and extending equipment operation while maintaining stability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS9157193B2Method for the installation of slab tracks in twin tube tunnels
Publication Date: 2015.10.13 FCC CONSTR SA

AI summary

A method is described for the installation of slab tracks in tunnels, in particular tracks on a slab of concrete, with the optimized design and execution characteristics, and substantially increased performance compared to the normal known methods. The method includes a succession of phases executed in order, with the help of an auxiliary track, Consisting of the design of the construction section, the construction of the railway yards, assembly of the auxiliary track from the evacuation platform, execution of the foundation base, assembly of the track in slabs, transitions from slab track—ballast track, and placement of long bars and welding.