Stability Prediction Of Roadway At Shaft Bottom Based On Geomechanical Characterization And Interpretation, With Special Reference To Daliu Colliery

Roadway at shaft bottom is one of the key parts in mine system, particularly for mine transportation, ventilation etc. The thesis is mainly conducted geological and geomechanical investigation on the roadway at shaft bottom by using rock mechanicals and geomechanics theories to determine the RMR of rock masses, and educe RF of rock mass strength parameters so as to calculate the strength characteristics of rock mass. Also the effect of fracture density (fracture spacing),strata dip and time on the stability of roadway at shaft bottom has been studied uing numerical modeling. The results indicated that the horizontal stress and horizontal displacement of surrounding rock reduced gradually with the fracture density decreasing (fracture spacing increasing),The rate of decrease of horizontal stress and horizontal displacement decreased with fracture density reducing (fracture spacing increasing),. The horizontal stress and horizontal displacement of rock have no significant changes,When the fracture spacing increased from 4m to 5m, and the fracture spacing has no effect on the stability of surrounding rock when the fracture spacing increased to 5m above. When strata dip increasing from 0°to 45°,the distribution of surrounding stress and displacement asymmetry appears. The stress and displacement of the left roof were significantly higher than the right roof, the stress and displacement of the right floor were significantly higher than the left floor. And the asymmetric distribution of stress and displacement are even more significant phenomenon, the roadway has become more unstable with the strata dip increasing, Therefore, the roadway support structure needs to be optimized and balance this asymmetric distribution of the stress and displacement through asymmetric support structure, to make the roadway stabilize. The deformation of roof,floor and rib will experience accelerated creep, creep slow and steady creep of the period. but this three creep cycles of the roof,floor and rib are not consistent, creep will not stop during the Roadway's useful life, so it requires continuous maintenance.