I-Patterned Filling for Coal Mine Roof Subsidence Control
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Solution Overview
Problem
Existing backfill mining methods in coal mining face challenges such as high costs, excessive equipment requirements, and immature filling technologies, which limit their development and application, particularly in underground coal mining, leading to issues like surface subsidence and environmental damage.
Innovation Solution
An I-patterned filling method is proposed based on roof fracture characteristics, using principles of virtual work and plastic mechanics to determine optimal filling positions and dosages, reducing material consumption and costs, and employing an I-patterned three-strip filling around internal plastic hinge lines to support fractured roofs effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional backfill mining methods (working face solid filling, roadway solid filling, working face paste filling) are used to control surface subsidence, then surface subsidence control is achieved, but filling material consumption and cost increase significantly
Solution Approach 1:
The patent applies local quality by identifying and treating only the key locations where roof fractures occur (plastic hinge lines and fracture zones) rather than filling the entire goaf area. The filling bodies are strategically placed at specific positions determined by roof fracture characteristics, achieving effective subsidence control with minimal material consumption.
Solution Approach 2:
The patent segments the continuous filling approach into discrete filling bodies placed at specific key locations. The goaf is divided into zones based on roof fracture patterns, and filling bodies are positioned at critical fracture zones and plastic hinge lines, transforming the filling process from a continuous area treatment to a segmented point-based treatment.
2Object-affected harmful factors
If comprehensive backfill mining methods are implemented to prevent surface subsidence, then environmental protection is improved, but equipment size and system complexity increase excessively
Solution Approach 1:
The patent extracts and focuses only on the critical elements needed for effective subsidence control - the key fracture zones and plastic hinge lines - rather than implementing a comprehensive filling system across the entire goaf. This extraction approach simplifies the filling system by removing unnecessary components and concentrating resources on the most critical areas.
3Stability of the object's composition
If traditional filling methods are used to support roof structures, then roof stability is maintained, but filling cost becomes prohibitively high
Solution Approach 1:
The patent applies preliminary action by calculating and determining the key locations of roof fractures and plastic hinge lines before implementing the filling operation. The filling body positions are pre-determined based on roof fracture characteristics and mechanical analysis, allowing for optimized material placement that ensures roof stability from the outset while minimizing material consumption.
Data Source
AI summary
An I-patterned filling method for an initial stage of coal mining based on roof fracture characteristics is provided. A relationship between an overburden load borne by a main roof and an overhang size is determined based on principle of virtual work and a surgery theory when an overhang distance of the main roof reaches an initial weighting interval to enter a plastic limit state with an advance of a working face to obtain the initial weighting interval. An initial fracturing interval of an immediate roof is obtained in the same way. According to a subsidence law of the main roof in an inverted hip roof form, the filling is performed at a key position around an internal plastic hinge line through I-patterned three-strip filling. Size parameters of the I-pattered filling are designed to prevent the immediate roof and the main roof from being fractured.