title: Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.
abstract: The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential.
authors.affiliation: State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, 266590 China ; School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing, 100083 China.
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Li
authors.affiliation: College of Geomatics, Shandong University of Science and Technology, Qingdao, 266590 China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Shi
authors.affiliation: School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing, 100083 China.
authors.forename: Renshu
authors.initials: R
authors.lastname: Yang
keywords: Deformation mechanism; Extremely swelling soft rock; Field monitoring; Mechanical model; Plastic zone; Swelling potential