Submerged Cable-Stayed Floating Tunnel Stability

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Solution Overview

Problem

The design and construction of submerged floating tunnels face challenges such as structural stability, adverse sea conditions, and maintenance difficulties, particularly in terms of buoyancy-to-weight ratio management and anchor system reliability, which hinder their development into practical projects.

Innovation Solution

A submerged cable-stayed floating tunnel structure incorporating a tunnel body, shore connecting structures, a cable anchor system, a buoyancy-to-weight ratio adjustment system, an anti-collision warning system, and an escape system, featuring a round or prismatic cross-sectional structure with a buoyancy-to-weight ratio adjustment device and stay cables anchored to the ground for stability and maintenance convenience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the floating tunnel is anchored to the seabed through tension legs or anchor cables, then the tunnel can maintain position in deep water, but the tunnel will be displaced or wobbled under hydrodynamic force

Engineering Contradiction:
Improveposition stabilityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies counterweight by using gravity-based stabilization where the tunnel's own weight and ballast systems counterbalance hydrodynamic forces. The tunnel structure incorporates weighted ballast compartments and gravity-based anchoring that resist displacement without requiring tension legs, thereby maintaining position stability while reducing structural wobbling under wave and current loads.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent implements dynamic adaptation through adjustable buoyancy modules and flexible mooring systems that can adapt to varying sea conditions. The tunnel incorporates movable ballast systems and dynamic tensioning mechanisms in the mooring lines that automatically adjust to wave periods and current speeds, transforming the rigid static structure into a dynamically responsive system that maintains stability without excessive displacement.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the tunnel gravity is greater than buoyancy, then the tunnel can be supported by anchor cables, but the tunnel is greatly affected by tide fluctuation in the vertical direction

Engineering Contradiction:
Improvevertical position stabilityVSAvoidtidal response stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by incorporating adjustable buoyancy modules that can dynamically modify the tunnel's overall buoyancy-to-weight ratio. These modules contain variable displacement ballast systems that can adjust the effective weight of the tunnel in real-time, compensating for tidal fluctuations and maintaining optimal vertical position stability regardless of tide conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control through sensors that continuously monitor the tunnel's vertical position, tide levels, and buoyancy forces. This data feeds into a control system that automatically adjusts ballast pump operations and buoyancy module activation to maintain stable vertical positioning, creating a closed-loop system that responds to tidal variations in real-time.

Inventive Principle:
Principle #23Feedback

3Reliability

If the tunnel gravity is smaller than buoyancy, then the tunnel can be anchored through tension legs, but the tunnel will be displaced under hydrodynamic force

Engineering Contradiction:
Improveanchoring reliabilityVSAvoidhorizontal position stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies counterweight principles by using gravity-based stabilization where the tunnel's own weight and ballast systems counterbalance hydrodynamic forces. The tunnel structure incorporates weighted ballast compartments and gravity-based anchoring that resist displacement without requiring tension legs, thereby maintaining position stability while reducing structural wobbling under wave and current loads.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent introduces intermediary elements in the form of gravity-based intermediate anchoring structures that mediate between the tunnel and the seabed. These intermediate structures act as passive stabilizers that distribute hydrodynamic loads across multiple contact points, reducing the displacement effect on the tunnel while maintaining anchoring reliability without requiring active tension leg systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of repair

If stay cables are used for support, then cable maintenance and replacement becomes convenient, but the anchor system complexity increases

Engineering Contradiction:
Improvecable maintenance accessibilityVSAvoidanchor system complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The patent applies the extraction principle by separating the cable anchoring function from the main tunnel structure. Stay cables are anchored to independent, modular anchor blocks that are detached from the tunnel body, allowing cables to be replaced or maintained by working on isolated anchor units rather than disrupting the entire tunnel structure. This extraction simplifies maintenance operations while managing anchor system complexity through standardization.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements segmentation by dividing the anchor system into modular, independent units distributed along the tunnel length. Each anchor block is a self-contained module with standardized cable attachment points, allowing individual segments to be maintained or replaced without affecting other parts of the system. This segmentation reduces overall complexity through modularity and standardization while improving maintenance accessibility.

Inventive Principle:
Principle #1Segmentation

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

The solution enhances structural stability, reduces the impact of adverse sea conditions, simplifies construction and maintenance, and ensures safer operation by maintaining a stable floating depth and facilitating cable monitoring and replacement, thus overcoming previous design and construction challenges.

Implementation Method 1

the floating tunnel structure is surrounded by water, is neither on the ground nor crossing the ground, but mainly depends on the gravity of its own structure, the buoyancy of the structure and the anchoring force of the support system to retain at a fixed position

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a support system (anchor cables anchored on the seabed, piers or buoyancy tanks on the water)

Methodology Applied
Scientific EffectTension: Tension

Implementation Method 3

mainly depends on the gravity of its own structure, the buoyancy of the structure and the anchoring force of the support system to retain at a fixed position

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3865627B1Submerged cable-stayed floating tunnel structure
Publication Date: 2023.08.30 CCCC THIRD HARBOR ENGINEERING CO LTD
  • EP3865627B1 patent drawingFigure 1~3
  • EP3865627B1 patent drawingFigure 4~6
  • EP3865627B1 patent drawingFigure 7~9

AI summary

Disclose in the present invention is a submerged cable-stayed floating tunnel structure, comprising a submerged floating tunnel, a pair of shore connecting structures, a cable anchor system, a buoyancy-to-weight ratio system adjustment, an anti-collision warning system and an escape system. The pair of shore connecting structures are respectively located on shore slopes on two sides; and the pair of shore connecting structures are respectively connected between two ends of the submerged floating tunnel and a pair of land slope tunnels, the submerged floating tunnel is formed by connecting a plurality of pipe segments; the cable anchor system employs a two-way single cable plane or a two-way double cable plane and comprises four cable receiving shafts, four groups of cable steering piers, cable ramps, and multiple strands of stay cables; the buoyancy-to-weight ratio adjustment system comprises a buoyancy-to-weight ratio adjustment device in a tunnel pipe segments and buoyancy-to-weight ratio adjustment devices in the shore connecting structures; the anti-collision warning system comprises a warning buoy device and a submerged warning anchor cable device; and the escape system comprises an automatic alarm system, an escape time extension system, and escape routes. The submerged cable-stayed floating tunnel structure in the present invention withstands pressure more reasonably, and reduces the impact of adverse sea conditions during construction.