Key Insights into Roadway Stability Amid Hard Roof Break in Mining

By Dr. Noopur JainReviewed by Laura ThomsonJul 12 2024

In a recent article published in the journal Scientific Reports, researchers from China investigated the dynamic response and roadway stability during mining operations under the influence of hard roof break. Understanding the effects of hard roof breaking on roadway deformation and stability is crucial for ensuring safe and efficient mining practices.

Background

The increasing demand for coal extraction has led to the exploitation of coal reserves in geologically complex environments. In underground mining operations, the presence of hard roof formations poses significant challenges to the stability and safety of roadways and working faces. Hard roof strata exhibit abrupt breaking behavior, releasing substantial energy that can trigger dynamic disasters such as roadway instability and rock bursts.

Understanding the dynamic response and stability of roadways under the disturbance of hard roof breaking is crucial for ensuring the safety and efficiency of mining operations. Previous studies have highlighted the detrimental effects of hard roof breaking on the surrounding rock mass, including stress concentration, plastic zone expansion, and roadway deformation patterns.

The Current Study

FLAC3D is a well-established software known for its capabilities in modeling complex geomechanical processes and was utilized to conduct simulations to analyze the dynamic response of rock structures under various loading conditions.

A dynamic calculation simulation method specifically designed for hard roof breaking was developed. This method enabled a comprehensive simulation of the entire process involved in working face excavation, hard roof breaking, and the subsequent dynamic response of the roadway.

Various parameters related to roadway response were analyzed during the simulations, including vibration velocity, stress distribution, and displacement patterns. These parameters provided insights into the dynamic behavior of the roadway surrounding rock under the influence of hard roof breaking.

The deformation patterns of the roadway before and after the first weighting and periodic weighting of hard roof breaking were carefully analyzed. To understand the extent of dynamic disturbances caused by hard roof breaking, specific focus was placed on the changes in deformation on different sections of the roadway, such as the roof, sidewalls, and floor.

Stress superposition theory was applied to analyze the total stress in the roadway surrounding rock, considering both static and dynamic disturbance stress. This assessment provided valuable insights into the potential risks of instability and rockburst associated with hard roof breaking. Data obtained from the simulations were analyzed to identify trends in stress distribution, deformation patterns, and stability levels of the roadway.

Results and Discussion

The simulations revealed significant changes in the dynamic response of the roadway surrounding rock during hard roof breaking. The release of energy from the breaking of the hard roof resulted in dynamic stress waves propagating through the surrounding areas, leading to alterations in stress distribution, plastic zone development, vibration velocity, and roadway deformation. These dynamic responses highlight the complex interactions between dynamic disturbances and the stability of underground structures.

The study observed a notable increase in stress concentration and expansion of the plastic zone in the roadway following the dynamic disturbance caused by hard roof breaking. The widening of plastic zones indicated a higher level of deformation and potential instability in the surrounding rock mass. This finding underscores the importance of considering dynamic disturbances, such as hard roof breaking, in assessing the overall stability of roadways in mining environments.

The analysis of roadway deformation patterns highlighted the significant impact of hard roof breaking on the stability of the structure. The roadway roof and the right side (mining side) were identified as the most affected areas by the dynamic impact of roof breaking. This observation suggests that the dynamic disturbances induced by hard roof breaking can lead to localized deformations and stress concentrations, posing challenges to the stability of the roadway.

Conclusion

In conclusion, the study highlights the critical role of hard roof breaking in influencing roadway stability and deformation patterns during mining operations. The findings underscore the importance of considering dynamic disturbances, such as hard roof breaking, in assessing and managing the risks associated with underground mining activities. Further research in this area is essential to develop effective strategies for enhancing roadway stability and ensuring the safety of mining operations.