Study on strength softening of surrounding rock in deep roadway at Daqiang coal mine

Abstract

With the deepening of coal mining, engineering support problems become more complex.In order to study the interaction between rock and water on the deformation and failure of roadway, the deep soft rock roadway of Tiefa Daqiang coal mine was chosen as the engineering sample, and a series of water absorption tests and strength softening tests on rock samples with different water content were conducted.The experimental results showed that water absorption processes were divided into two stages:deceleration phase and constant phase and the water absorbing capacity of rock with a certain pressure is larger than the one without pressure. The results of strength softening showed that the uniaxial compressive strength of sandstone and mudstone has a negative relationship with water absorption time and water content.The initial intensity of water absorption decreased rapidly, and the surrounding rock should be timely closed and remove moisture after excavation, because it can prevent the sudden declining in the strength of the surrounding rock which may cause the floor heave and large deformation.The results are of great significance to design, construction and safety of deep mining engineering.

Keywords

• deep rock
• water absorption characteristics
• hydrophilic mechanism
• rock softening
• roadway support