Study on the limit angle of mining subsidence basin based on the field survey data in the mining area

Study on the limit angle of mining subsidence basin can reflect the influence on environment due to the underground coal excavation. In this paper, a large number of observation station data of ground movement in mining filed had been collected in order to study the relationship between the limit angle of mining subsidence basin and unconsolidated layer thickness and bedrock thickness. Based on these field survey data, the regression relationships between the trend limit angle, the downward limit angle, the upward limit angle and the ratio of unconsolidated layer thickness and bedrock thickness have been established. The conclusions showed that with the increase of unconsolidated layer thickness and bedrock thickness, the limit angle decrease. It provides a new way to determine the limit angles in mining areas.