In the depths of underground engineering projects, where the stability of surrounding rocks is paramount, a new study sheds light on the often-overlooked factor of water-rock interaction. Led by WANG Lunan of Liaoning Petrochemical University and published in *Yantu gongcheng xuebao* (translated as *Chinese Journal of Geotechnical Engineering*), the research delves into how water-rock interactions can compromise the integrity of granulite, a type of metamorphic rock commonly encountered in deep underground engineering.
The study, conducted by WANG Lunan and colleagues from Liaoning Petrochemical University and Hubei University of Arts and Science, employed uniaxial compression tests, digital image correlation technology, and microstructure tests to investigate the changes in granulite’s mechanical properties and local damage over time when exposed to different solutions. The findings reveal a nonlinear deterioration in the rock’s elastic modulus and uniaxial compressive strength as immersion time increases, with mine water causing more significant damage than distilled water—at least initially.
“With increasing immersion time, both the elastic modulus and uniaxial compressive strength decrease nonlinearly,” WANG explained. “The deterioration of mechanical properties in mine water is more serious than that in distilled water; however, the difference can be neglected after soaking for 150 days.”
The research also highlights the progression of local damage in granulite under axial loading, which transitions from homogenization to localization and eventually to fracture. The damage severity factor increases nonlinearly, particularly after peak stress, while the damage localization factor decreases fluctuantly, stabilizing post-peak stress. Notably, water-rock interactions accelerate this damage development, with mine water exacerbating the effects more than distilled water.
On a microstructural level, the study found that water-sensitive substances in granulite react with solutions, leading to pore development, increased pore sizes, and fragmented microstructures. “The microstructures in mine water are more deteriorated,” WANG noted, underscoring the profound impact of water-rock interactions on the rock’s integrity.
For the energy sector, these findings are particularly relevant. Underground engineering projects, such as mining and oil and gas extraction, often involve granulite and other rocks subjected to water-rock interactions. Understanding how these interactions affect mechanical properties and damage evolution can inform better design and safety measures, ultimately reducing the risk of instability and failure in these critical infrastructure projects.
As the energy sector continues to push the boundaries of deep underground engineering, this research provides valuable insights into the long-term behavior of rocks under varying conditions. By acknowledging and mitigating the effects of water-rock interactions, engineers can enhance the stability and longevity of their projects, ensuring safer and more efficient operations.
The study, published in *Yantu gongcheng xuebao*, offers a comprehensive look at the complex interplay between water and rock, paving the way for future developments in the field. As WANG and his team continue to explore these dynamics, their work promises to shape the future of underground engineering, benefiting the energy sector and beyond.