Continuous 3D-Printed Shield Tunnel Lining With Rapid Cooling
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Solution Overview
Problem
Current 3D printing technologies for shield tunnel construction face challenges such as seamless integration of segments, lack of cooling devices for rapid solidification, and limited speed in forming tunnel linings, leading to inefficient and costly construction processes.
Innovation Solution
A 3D printing-based device with an extrusion assembly, heating and transportation assembly, cooling assembly, speed control assembly, and control system, including a lining forming mold, molten printing material transport pipes, and cooling jackets, to ensure seamless, continuous, and efficient tunnel lining formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional shield machine and tunnel lining segments are used, then the tunnel construction can be completed, but the transportation costs and construction costs are extremely high due to the heavy weight of components requiring transportation over hundreds of kilometers
Solution Approach 1:
The patent applies preliminary action by pre-heating the printing material before extrusion and preparing the support structures in advance. The material is heated to melting temperature before being extruded through the print head, ensuring proper flow and bonding characteristics during the printing process. This preliminary preparation enables on-site construction without expensive transportation of pre-fabricated heavy segments.
Solution Approach 2:
The patent replaces the traditional mechanical system of transporting heavy pre-fabricated segments with a 3D printing system that extrudes and deposits material layer by layer on-site. Instead of moving heavy components hundreds of kilometers, the system uses a robotic arm with a print head to construct the lining segments in place, dramatically reducing transportation costs and energy consumption.
2Productivity
If traditional stationary TBMs are used for placing segments, then the tunnel lining can be constructed, but the construction efficiency is significantly reduced due to inability to operate continuously
Solution Approach 1:
The patent implements continuity of useful action through the automated 3D printing system that can operate continuously without interruption. The robotic arm with heating and extrusion capabilities maintains continuous deposition of printing material, eliminating the stopping and starting inherent in traditional segment placement methods. The system can print lining segments continuously as the shield machine advances, significantly improving construction efficiency.
Solution Approach 2:
The 3D printing system is self-service in that it automatically extrudes, deposits, and bonds the printing material without requiring external intervention for each layer. The integrated heating and extrusion system self-regulates the material flow and bonding process, enabling continuous operation without manual intervention or frequent stops for repositioning equipment.
3Loss of energy
If 3D printing technology is used for on-site tunnel lining construction, then transportation costs are reduced, but the construction speed is limited and cannot achieve efficient printing according to actual conditions
Solution Approach 1:
The patent applies dynamics by making the heating temperature and extrusion speed adjustable based on real-time conditions. The heating system can dynamically adjust the temperature of the printing material, and the extrusion rate can be varied according to the construction progress and material properties. This dynamic control enables the system to optimize printing speed while maintaining quality, overcoming the speed limitations of conventional 3D printing.
Solution Approach 2:
The patent utilizes parameter changes by varying the heating temperature, extrusion rate, and cooling conditions to optimize the printing process. The material temperature is controlled within a specific range to ensure proper flow and bonding, while the extrusion parameters are adjusted according to the desired construction speed. These parameter changes enable the system to achieve both cost efficiency and improved construction speed.
4Manufacturing precision
If 3D printing is used for tunnel lining, then complex models can be created with high forming accuracy, but the lack of cooling devices prevents rapid solidification and increases construction time
Solution Approach 1:
The patent applies phase transitions by controlling the melting and solidification of the printing material. The material is heated to a molten state for extrusion, then rapidly cooled to solidify and form the desired structure. This controlled phase transition enables both high forming accuracy and rapid solidification, as the material can be precisely deposited in molten form and then quickly set upon cooling.
Solution Approach 2:
The patent uses preliminary action by pre-heating the printing material before extrusion and providing support structures in advance. The material is brought to the appropriate temperature and flow characteristics before deposition, ensuring high forming accuracy. Simultaneously, the support structures are prepared beforehand to facilitate rapid solidification and cooling, reducing construction time.
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 device enables stable and integrated tunnel lining formation, reduces construction time, and lowers costs by allowing continuous printing and adjustment to environmental conditions, enhancing construction efficiency and quality.
Implementation Method 1
the molten printing material transport pipe is equipped with a heating device to maintain a temperature of the material during transportation in the molten printing material transport pipe
Implementation Method 2
the cooling assembly includes a first lining cooling jacket and a second lining cooling jacket
Data Source
AI summary
The present disclosure provides a 3D printing-based device for shield tunnel lining formation, which utilize a more rapid and efficient extrusion process. Solid printing materials are fed into a specially structured tunnel forming mechanism via a pneumatic conveying system. In conjunction with a lining cooling jacket and a shield machine's advancement control device, the 3D printing-based device enables continuous 3D printing of the tunnel lining.