INFLUENCE OF THE STRATIFICATION IN ROCK MASS ON THE STABILITY OF ROADWAYS IN VIETNAMESE COAL MINES

Abstract

When the excavation of roadways in the rock mass for underground mining the state of initial stress in the rock mass will be changed, otherwise established the new stress state in rock mass (the secondary stress state after excavation) around openings, respectively. The secondary stress state in rock mass has influence on the design and stability of roadways. Recently the estimation values of stress and deformation around roadways in underground mines when they are excavated in bedding rocks is limited problem. One of many factors concerns to the values and directions of the earth pressure on the steel supports is ratio between span of roadways and thickness of rock mass layers. This paper introduces the assessment of the stress and deformation around roadways and internal forces in the steel supports to determinate suitable locations of the friction joints of steel ribs in the roadways when consideration to change span ratio of roadways and thickness of rock mass layers in bedding rocks in the Quang Ninh underground mines of Viet Nam.