Stability Evaluation and Grouting of Abandoned Coal Mines Used for Building Constructions

This paper presents a case study of the grouting improvement of high-rise buildings built over an abandoned coal mine where several seams were mined out. The engineering behavior of the subsided land and its stability before and after grouting plays an important role in its use for construction and ecological development. The stability, suitability, and grouting efficiency for a case study of the Hupan Buildings built over an abandoned mined-out area in Xuzhou, Jiangsu, China were investigated through an in situ investigation and a theoretical analysis. Grouts with water-solid ratios of 1:1 and 1:1.5 were injected into the abandoned mined-out panels through 185 boreholes. The study area can be divided into three zones with different stability and suitability. Four detection boreholes were drilled for evaluating the grouting efficiency. The results show that the stability of the mined-out area was improved by grouting. The study provides a good basis for the construction and ecological use of subsided land.