Pumpable Crib Bag With Segmented Wire Hoops
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Solution Overview
Problem
Existing grout bags used in mine support are expensive due to elaborate reinforcing structures and require significant labor for installation, with insufficient load-carrying capacity, typically supporting around 125 tons to 150 tons with 9″ of displacement.
Innovation Solution
A pumpable crib bag assembly featuring a cylindrical bag with an inner mesh reinforcement that is permeable to liquid settable grout, equipped with a one-way valve and external reinforcement retainers, allowing for increased load capacity by prestressing between the mine roof and floor with pumped grout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elaborate reinforcing structures are employed in grout bags, then structural strength is improved, but manufacturing cost increases
Solution Approach 1:
The reinforcing structure is divided into multiple wire hoops spaced at intervals along the bag length, rather than using continuous elaborate reinforcement. This segmentation provides necessary structural strength while reducing material usage and manufacturing cost.
Solution Approach 2:
Wire hoops are strategically positioned at locations requiring additional strength (such as ends and intermediate sections), providing localized reinforcement where needed rather than uniform elaborate reinforcement throughout the entire bag, thus optimizing both strength and cost.
2Strength
If elaborate reinforcing structures are employed in grout bags, then structural strength is improved, but installation labor increases
Solution Approach 1:
The bag is designed with segmented wire hoops that are simpler and faster to attach compared to elaborate continuous reinforcement structures, reducing installation time and labor while maintaining necessary structural strength.
Solution Approach 2:
The wire hoop reinforcement system uses simple, inexpensive components that can be quickly installed and serve their purpose effectively, replacing the need for complex, labor-intensive reinforcement systems.
3Ease of manufacture
If standard grout bag design is used, then manufacturing simplicity is maintained, but load-carrying capacity is insufficient
Solution Approach 1:
The wire hoops are designed with optimized spacing (e.g., every 2-3 feet) and appropriate diameter to increase load-carrying capacity while maintaining manufacturing simplicity. The spacing and dimensions are carefully selected parameters that balance structural performance with ease of construction.
Solution Approach 2:
The combination of the fabric bag material with wire hoop reinforcement creates a composite structure that achieves higher load-carrying capacity than either material alone, while keeping the overall design simple and manufacturable.
4Reliability
If the bag material is made non-permeable to air, then grout retention is improved, but air escape becomes problematic during filling
Solution Approach 1:
An air escape port is provided as an intermediary component that allows air to escape during filling operations. This separate air escape pathway enables the use of non-permeable bag material for grout retention while solving the air entrapment problem during filling.
Solution Approach 2:
The air escape function is extracted as a separate feature (air escape port) from the bag material itself, allowing the bag material to be fully non-permeable for grout retention while the separate port handles air escape during filling.
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 pumpable crib bag achieves a residual load capacity of 200 tons to 212 tons over a larger displacement range compared to standard inflatable crib bags, maintaining load-carrying capacity beyond initial peak, with improved structural integrity and reduced labor costs.
Implementation Method 1
The inner generally cylindrical mesh reinforcement is spaced from the inner wall of the bag and is permeable to the liquid settable grout whereby the liquid settable grout may be pumped through a fill port into the bag to thereby fill the bag and encapsulate the mesh reinforcement
Implementation Method 2
The fill port for the liquid settable grout extends into the interior of the mesh reinforcement and includes a one-way valve to prevent the liquid settable grout from exiting the bag from the fill port when the bag is completely filled under pressure
Implementation Method 3
The bag and the internal mesh reinforcement include external reinforcement retainers for reinforcing the bag and the mesh reinforcement in order to minimize lateral bulging
Implementation Method 4
The bag together with its internal mesh reinforcement is axially collapsible for storage, transportation and for adaptable inflatability
Implementation Method 5
The grout bags generally are filled with a liquid settable grout which sets solid using cementitious or other suitable binding material
Data Source
AI summary
A pumpable inflatable crib bag assembly for supporting a mine roof which includes a generally cylindrical bag having top and bottom ends for retaining and confining a liquid settable grout to be pumped into the bag. The bag further includes an inner generally cylindrical mesh reinforcement disposed within and generally coextending with the bag. This generally cylindrical mesh reinforcement is spaced from an inner wall of the bag and is permeable to the liquid settable grout whereby the liquid settable grout may be pumped through a fill port into the bag to thereby fill the bag and encapsulate the mesh reinforcement. The liquid settable grout is pumped through a fill port which is adjacent the top end of the bag.