Underwater Blasting Ship Anchoring and Cushioning for Caisson Foundations

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Solution Overview

Problem

Current underwater open caisson foundation construction methods are inefficient, as they do not effectively utilize the bearing capacity of hard rocks, leading to excessive blasting and concrete pouring, high costs, and poor surface flatness, requiring time-consuming mechanical chiseling for adjustments.

Innovation Solution

An underwater blasting construction method using a chain gravity anchor to stabilize the reef blasting ship, allowing for targeted drilling and blasting in distinct areas with an energy dissipation composite cushion layer to reduce shock wave damage and achieve a flatter surface, thereby optimizing rock bearing capacity and reducing excavation volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If continuous charging structure is adopted for underwater blasting, then the blasting effect is strong, but the damage to the bottom surface is large and the flatness is poor

Engineering Contradiction:
Improveblasting effectVSAvoidflatness of blasting bottom surface
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent divides the blasting operation into multiple sequential stages (first stage, second stage, third stage) with different charging structures. The first stage uses continuous charging for strong blasting effect, while the second and third stages use cushioned charging to protect the bottom surface and achieve flatness, thus resolving the contradiction between blasting strength and surface quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an energy dissipation composite cushion layer at the bottom of blasting holes in the second and third stages. This cushion layer absorbs and dissipates the explosion shock wave energy before it reaches the bottom surface, preventing excessive damage and achieving the desired flatness while maintaining effective blasting.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If complete blasting and excavation is performed without considering rock bearing capacity, then the foundation construction is simplified, but the excavation amount is large and cost is high

Engineering Contradiction:
Improvefoundation construction simplicityVSAvoidexcavation amount
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent applies different blasting strategies to different areas: the first area undergoes complete blasting to expose the central rock platform, while the second and third areas use cushioned blasting to preserve the bearing capacity of hard rocks. This selective approach reduces unnecessary excavation while maintaining construction simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the charging parameters (from continuous to cushioned charging) in different stages and areas to optimize the balance between excavation efficiency and rock bearing capacity utilization, thereby reducing the total excavation amount while keeping the construction process manageable.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If mechanical chiseling is used to improve blasting surface flatness, then the construction condition is improved, but the process is time-consuming and labor-consuming

Engineering Contradiction:
Improvesurface flatnessVSAvoidconstruction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical chiseling process with an optimized blasting system that uses energy dissipation composite cushion layers and multi-stage charging. This substitution achieves the desired surface flatness through controlled explosion physics rather than mechanical removal, significantly improving construction efficiency while maintaining surface quality.

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

4Device complexity

If reef blasting ship is not anchored stably, then the construction equipment is simple, but the blasting precision and quality cannot be guaranteed

Engineering Contradiction:
Improveanchoring system complexityVSAvoidblasting precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements stable anchoring of the reef blasting ship using chain gravity anchors before commencing blasting operations. This preliminary action ensures the ship remains stationary and precisely positioned throughout the multi-stage blasting process, guaranteeing blasting precision without requiring overly complex real-time adjustment systems.

Inventive Principle:
Principle #10Preliminary action

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 method significantly reduces the amount of blasting rock and concrete needed, saves economic costs, and facilitates faster and more efficient construction by fully utilizing the substrate's bearing capacity and improving surface flatness, making subsequent processes more manageable.

Implementation Method 1

the chain gravity anchor comprises a steel wire rope and a plurality of gravity anchors

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

the contact area between the gravity anchor and the river bed can be increased, the friction between the gravity anchor and the river bed can be increased

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

the damage degree of explosion shock waves generated by the charging mode to the bottom surface of the foundation pit is large

Methodology Applied
Scientific EffectShock wave: Shock Wave

Implementation Method 4

underwater drilling and blasting has high production efficiency, good blasting effect

Methodology Applied
Scientific EffectExplosion: Explosion

Implementation Method 5

setting an energy dissipation composite cushion layer at the bottom of a blasting hole; which can effectively reduce the damage of blasting energy to the rock layer at the bottom of the pit

Methodology Applied
Scientific EffectEnergy dissipation: Damping

Data Source

PatentEP4428305A1Underwater blasting construction method for embedded open caisson deep water foundation
Publication Date: 2024.09.11 CHINA RAILWAY NO 4 ENG GRP CO LTD
  • EP4428305A1 patent drawingFigure 1
  • EP4428305A1 patent drawingFigure 2~3
  • EP4428305A1 patent drawingFigure 4~5

AI summary

An underwater blasting construction method for embedded open caisson deep water foundation, including the following steps: determine a construction area; make and install a chain gravity anchor; tow the reef blasting ship to the construction area by using a tugboat; anchor the reef blasting ship; at least one anchor cable of the reef blasting ship is docked with a floating cable of the chain gravity anchor; sequentially carry out the steps of drilling, charging, blasting and slag cleaning in the first area, exposing the upper surface of a central rock platform; sequentially carry out the steps of drilling, charging, blasting and slag cleaning in the second area, exposing part of the side surface of the central rock platform and part of the surface of an outer side slope; sequentially carry out the steps of drilling, charging, blasting and slag cleaning in the third area, exposing the remaining side surface of the central rock platform, the remaining surface of the outer side slope and the surface of an annular groove; the steps of drilling, charging and blasting which are sequentially carried out in the first area, the second area and the third area are realized through the reef blasting ship; retract the chain gravity anchor by using the floating cable.