Abstract:
Due to the existing of the abandoned roadway, the rock above the working face and abandoned roadway is prone to fracture, which brings great risks to the production and construction of coal mine.Supporting the abandoned roadway is an effective measure to improve the stress state of the rock and ensure its stability.Currently, the abandoned roadway is mainly supported by the concrete pier.According to the field experience, improving the bearing capacity of the pier will seriously affect the service life of the pick and the advancing speed of the working face.To solve the above problems, a new type of composite structure pier composed of filling material, internal structure, and external mold is developed by analyzing the deformation mechanism of rock around the abandoned roadway and mining face.and carries out the indoor test with the ratio of 1:1 to test the bearing capacity of the new composite structure pier.The results show that the new composite structure pier is applied in the actual project, the integrity of rock mass above the roof is good in the process of working face advancing, and there is no fracture failure phenomenon.At the same time, the time of fully mechanized top coal caving face passing through the empty roadway is shortened from 15 days to 3 days, which greatly improves the production efficiency.