Bidirectional Static-Dynamic Loading Test Device for Mine Roof Key Block Instability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods lack a comprehensive approach to study the instability mechanism of key blocks in mine roofs under bidirectional static-dynamic stress conditions, which is crucial for early warning and prevention of roof fall accidents, as they primarily focus on unidirectional dynamic loads and do not provide sufficient precursor information for disaster prevention.
Innovation Solution
A fall test device and method utilizing bidirectional static-dynamic loading, incorporating an overall frame with horizontal and vertical pressure loading systems, pendulum-hammer and drop-hammer impact disturbance systems, and advanced monitoring systems to simulate and analyze the instability process of key blocks, providing precursor information for disaster prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If unidirectional dynamic load testing is used, then the test device complexity is reduced, but the reliability of studying key block instability under realistic bidirectional stress conditions deteriorates
Solution Approach 1:
The test device is divided into separate horizontal and vertical loading systems, each independently capable of applying static and dynamic loads. This segmentation allows the complex bidirectional loading function to be achieved through modular, manageable components rather than a monolithic complex system.
Solution Approach 2:
Each loading system (horizontal and vertical) is designed to perform multiple functions: applying both static loads and dynamic impact loads. The horizontal system uses a pendulum hammer for dynamic loading, while the vertical system uses a drop hammer, allowing each subsystem to handle both static and dynamic conditions universally.
2Measurement precision
If bidirectional static-dynamic loading systems are implemented, then the measurement precision of instability precursor information is improved, but the device complexity increases
Solution Approach 1:
Multiple monitoring systems are pre-configured to detect precursor information before key block failure occurs. The acoustic emission monitoring, strain gauge monitoring, and displacement monitoring systems are all set up in advance to capture early signs of instability, allowing precise measurement of precursor conditions before the actual failure event.
3Loss of information
If comprehensive monitoring systems are added to capture precursor information, then the loss of information is reduced, but the device complexity increases
Solution Approach 1:
Multiple monitoring functions (acoustic emission detection, strain measurement, displacement tracking) are integrated into a unified monitoring system that operates simultaneously during bidirectional loading tests. This merging allows comprehensive information capture without requiring separate independent systems for each measurement type.
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
Enables thorough analysis of key block instability processes, offering precursor information and critical instability conditions, thus enhancing the theoretical foundation for disaster prevention and early warning in mine roof stability assessments.
Implementation Method 1
a horizontal pendulum-hammer impact disturbance system... applies a horizontal dynamic load to the model sample by hitting against a horizontal incident rod
Implementation Method 2
a vertical drop-hammer impact disturbance system... applies a vertical dynamic load to the model sample by hitting against a vertical incident rod
Implementation Method 3
a horizontal pressure loading system... apply a horizontal static load to the model sample... a vertical pressure loading system... apply a vertical static load to the model sample
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A key roof block fall test device and method based on bidirectional static-dynamic loading are disclosed. The test device comprises an overall frame, a horizontal pressure loading system, a vertical pressure loading system, a horizontal pendulum-hammer impact disturbance system, a vertical drop-hammer impact disturbance system, an incident stress wave monitoring system and a response measurement and monitoring system. The test method includes a first working condition and a second working condition, wherein in the first working condition, a bidirectional static-dynamic loading disturbance test of an overall roadway model sample is carried out to explore the initial stress state of roadway surrounding rock and the initial stress condition of key roof block, so as to observe the crack propagation rule, the formation process of a key block and the instability process of the key block under the dynamic disturbance; and in the second working condition, the key block and the surrounding block on both sides are extracted based on results of the first working condition to carry out a bidirectional static-dynamic loading disturbance instability test on a key block model sample, so as to more accurately explore the rule of crack propagation caused by stress waves, the critical condition of instability sliding of the key block, and the action mechanism of instability caused by disturbances.