Assessment of roadway stability supported by a bolt–mesh–shotcrete system at the Mao Khe vertical shaft project

Abstract

As underground coal mining extends to greater depths, increasing ground pressure poses significant challenges to roadway stability, necessitating the adoption of effective support solutions. The combined support system consisting of rock bolts, steel mesh and shotcrete (B–M–S) has gradually been studied and applied in several underground coal mines in Vietnam; however, systematic evaluation of roadway stability supported by this system remains limited. This paper presents an assessment of roadway stability supported by the B–M–S system at the Mao Khe vertical shaft project using a combination of numerical simulation and in-situ displacement monitoring. A numerical model was developed with FLAC3D to analyze and compare boundary displacements between the steel arch support scheme and the B–M–S support scheme. In addition, field measurements of roadway boundary displacements were carried out over a 90-day monitoring period using surveying instruments. The results show that the B–M–S support system significantly reduces roof and sidewall displacements compared with steel arch support. All measured displacement values remain within allowable limits and tend to stabilize over time, demonstrating the effectiveness and applicability of the B–M–S support system under the geological conditions of the Mao Khe project.