ANALYSIS OF RESIDUAL SUBSIDENCE MOVEMENTS IN THE UK COALFIELDS

The importance of residual subsidence in the study of ground movement due to mining is discussed and previous research results are briefly r eviewed. On the basis of ten cases investigated within the UK coalfiel ds, the difference between residual subsidence characteristics along l ongitudinal and transverse lines is studied. Particular attention is p aid to the four key positions along the subsidence profile, i.e. the s ubsidence limit position, the half-subsidence position, the rib-side p osition and the central position. A case example associated with minin g an inclined seam is investigated in detail, showing that different r esidual subsidence characteristics appear due to mining an inclined se am as opposed to a level seam. Additionally, a prediction model is pre sented and applied to determine the duration of residual subsidence. T he model theoretically indicates the main factors controlling the peri od of residual subsidence. Finally, an empirical equation, based on da ta collected within the UK coalfields, for estimating the duration of residual subsidence is put forward with consideration of both depth an d geological factors. This is believed to be an important tool for civ il engineers to calculate the time span after which no precautions nee d be taken to protect surface buildings from further damage due to res idual subsidence movements.