Modular Tunnel Lining System Using Inflatable Mandrel
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Solution Overview
Problem
Current methods for repairing man-entry sewers, such as trenchless piping, are inefficient and costly due to the need for trench digging and diverting water flow, making it difficult to repair larger tunnels while they are in use.
Innovation Solution
A modular tunnel lining system using radial liner sections and elongate supports that can be assembled and tensioned within the tunnel through existing manholes, allowing for trenchless repair and installation while the sewer is in operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If trenchless piping methods are used to repair man-entry sewers, then the need for trench digging is avoided, but the complexity of the repair process increases due to the need for water flow diversion and drainage
Solution Approach 1:
The repair system is divided into modular segments including inflatable mandrels of different sizes, segmented liner sections, and modular coupling mechanisms. This segmentation allows the system to adapt to various tunnel diameters and repair lengths without requiring complete water flow diversion, as repairs can be performed in manageable sections while maintaining flow in other areas.
Solution Approach 2:
The inflatable mandrel provides a dynamic, adjustable support structure that can be inflated to different pressures and diameters to match the specific tunnel being repaired. This dynamic adaptation eliminates the need for pre-configured rigid structures and allows the system to work effectively across different tunnel sizes and water flow conditions without requiring complete drainage.
2Ease of operation
If water flow is diverted or stopped for tunnel repair, then access to the tunnel is improved, but substantial time and cost are incurred
Solution Approach 1:
The inflatable mandrel is inserted and positioned within the tunnel before the liner installation begins. This preliminary action creates a stable working environment and supports the liner sections as they are installed, allowing repair work to proceed without requiring complete water flow cessation. The mandrel remains in place throughout the liner installation process, providing continuous support.
Solution Approach 2:
The inflatable mandrel acts as an intermediary structure between the flowing water and the liner being installed. It provides a stable platform for liner installation while allowing water to flow around or over it, thereby maintaining tunnel functionality during repair operations and eliminating the need for complete water flow diversion.
3Ease of operation
If the tunnel is drained for repair work, then the repair environment is improved, but substantial cost and unsettlement in the relevant location occur
Solution Approach 1:
The inflatable mandrel serves as a mediator that creates a controlled repair environment without requiring complete tunnel drainage. It allows water to flow while providing a dry, stable workspace for liner installation, thereby eliminating the harmful effects of drainage-related unsettlement in surrounding areas while maintaining an adequate repair environment.
4Area of stationary object
If large size repair panels are passed into the tunnel through trenches, then the repair coverage is improved, but the complexity of access infrastructure increases
Solution Approach 1:
The liner repair system is divided into smaller, manageable liner sections that can be installed sequentially through existing manholes. Each liner section is coupled to the previous section using modular coupling mechanisms, achieving complete tunnel coverage without requiring large repair panels or extensive trench infrastructure.
Solution Approach 2:
Instead of accessing the tunnel through horizontal trenches, the system utilizes the vertical dimension by inserting inflatable mandrels and liner sections through existing vertical manholes. This dimensional change eliminates the need for complex trench infrastructure while achieving complete circumferential and longitudinal coverage of the tunnel.
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
Enables efficient and cost-effective repair of man-entry sewers by avoiding trench digging and allowing for installation with flowing water, using pre-formed radial liner sections and tensioners to form a watertight seal without being compromised by debris.
Implementation Method 1
a tensioning mechanism in the form of a jack screw arranged to apply a circumferential tension to the liner sections
Implementation Method 2
compressing them against the tunnel inner surface to form a watertight seal
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A modular man-entry tunnel lining system for a tunnel having a manhole access and an elongate tunnel inside surface, the system at least comprising: a plurality of sets of pre-formed radial liner sections; a plurality of elongate liner section supports; and a plurality of tensioners; wherein all of the radial liner sections, liner section supports and tensioners are transportable through the manhole access, and each set of the radial liner sections can assemble to form a length of a liner around at least a portion of the inside surface of the tunnel, and the sets of radial liner sections are supported by the elongate support sections and tensioned in place by the tensioners.