Rail Subgrade Repair Using Gravel-Spoil Composite Layer
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Solution Overview
Problem
Existing methods for rehabilitating track beds struggle to optimize the quality and uniformity of the intermediate layer, particularly in achieving consistent height and composition.
Innovation Solution
The method involves supplementing usable overburden with gravel, utilizing a screening process to ensure uniform quality and constant height of the intermediate layer by adding aggregates as needed, and employing conveyor belts and clearing chains to manage material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If usable overburden is used directly without supplementation, then the process is simple and quick, but the quality and uniformity of the intermediate layer cannot be optimized
Solution Approach 1:
The patent applies preliminary action by preparing and storing supplementary gravel materials before the rehabilitation process begins. The screening plant pre-processes ballast into reusable aggregates, and these are stored in hopper (22) ready for supplementation. This ensures that when overburden quality is insufficient, uniformly graded gravel can be immediately added to achieve the required intermediate layer specifications without compromising quality.
2Stability of the object's composition
If overburden composition varies, then material availability is flexible, but the consistency of intermediate layer height and quality deteriorates
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition and quantity of supplementary gravel based on the specific characteristics of the available overburden. The screening plant adjusts the size distribution of reused ballast aggregates, and the deflection device (21) controls the quantity of gravel added from hopper (22). This allows the mixture to be optimized for each specific case, achieving consistent intermediate layer quality despite variations in overburden composition.
Solution Approach 2:
The patent applies composite materials by creating a mixed composition of overburden and supplementary gravel. The intermediate layer consists of a composite material formed by combining locally available overburden with screened and graded gravel aggregates. This composite approach leverages the advantages of both materials - the availability and cost-effectiveness of overburden combined with the uniformity and quality control of processed gravel - to achieve consistent layer properties.
3Manufacturing precision
If gravel supplementation is added to overburden, then the quality and height uniformity of intermediate layer is improved, but the process time and operational complexity increase
Solution Approach 1:
The patent applies universality by designing a multi-functional integrated system where the screening plant serves multiple purposes: cleaning ballast, producing reusable aggregates for supplementation, and controlling material grading. The same conveyor system (20) and deflection device (21) that manage gravel distribution also control the supplementation process. This multi-functionality reduces the need for separate dedicated equipment, thereby limiting the increase in operational complexity and process time despite the added supplementation step.
Data Source
Figure 1~2
AI summary
In a method for repairing a subgrade of a rail bed, the rail bed is removed in two stages in the form of an upper ballast layer (4) and a residue processing layer (7) thereunder. The upper ballast layer (4) is then cleaned, with accumulation of ballast (9) and spoil (10), wherein usable spoil (10) is dumped onto an exposed subgrade (11), levelled and compressed to form an intermediate layer (14). Gravel (17) is added to the usable spoil (10).