Abstract
Gypsum mines in China are mostly exploited through room and pillar mining. Due to backward mining technology and a long history of mining, a great number of pillars were left in gypsum mines. Many serious work safety accidents occurred as the result of goaf instability in history, which posed severe threats to the security of people’s lives and property. Based on the characteristics of surrounding rock damage, this research improved the constitutive equation of gypsum rock mass damage by establishing a damage evolution model and introducing a shape parameter. Meanwhile, the cusp catastrophe equation was deduced based on the catastrophe theory and the constitutive equation of gypsum rock mass damage, thus summarizing the criteria for pillar instability; the pillar safety factor was obtained by means of the interrelation between pillar load and pillar strength. Based on the criteria for pillar instability and the pillar safety factor obtained, the necessary and sufficient conditions for pillar stability were concluded. These conclusions are of significance in that they provide theoretic reference for the treatment of gypsum goaf, as well as for further mining.
Highlights
Seventy percent of gypsum mines in China are exploited through underground mining [1,2], or to be specific, room and pillar mining
When the number of mined areas exceeds the critical points, the untimely treatment often leads to rock collapse and strata dislocation with shock airflows and noises in the stope and roadway, which cause serious casualties and ground pressure disasters like surface cracking and damage, ground-building subsidence and collapse, and rock burst in the mining area
When the decrease reaches a certain degree, sudden catastrophic instability occurs within the pillar
Summary
Seventy percent of gypsum mines in China are exploited through underground mining [1,2], or to be specific, room and pillar mining. The locations of high stress (especially tensile stress) or in soft overburden rocks and unfavorable geological structure development are highly likely to become the breakthrough point for large-area sudden collapse and strata movement, causing devastating consequences to production and safety. Other methods related to rock damage were used to study goaf pillars, such as numerical methods, finite element method (FEM), extended FEM (X-FEM), and phase field [6–12]. These above-mentioned methods, cannot reflect the pillar damage from the nature of gypsum rock damage. The aim of this paper was to master the failure laws of pillars and to lay a solid theoretic foundation for feasible solutions to maintain the pillar and even the goaf stability of gypsum mines, promoting the sustainable development of mining
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
