Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also under-taken to assist in the control of floor heave.
In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures using the finite difference method(FLAC3D) combined with comparative analysis and typical engineering application at Xingcun coal mine. It is indicated by the analysis that the simple symmetric support systems used in the past led to destruction of the deep rock roadway from the key zone and resulted in the deformation of asymmetric floor heave in the roadway. Suitable reinforced support countermeasures are proposed to reduce the deformation of the floor heave and the potential risk during mining. The application shows that the present support technology can be used to better environmental conditions. The countermeasures of asymmetric coupling support can not only effectively reduce the discrepancy deformation at the key area of the surrounding rock mass, but also effectively control floor heave, which helps realize the integration of support and maintain the stability of the deep rock roadways at Xingcun coal mine.
Sun XiaomingWang DongFeng JiliZhang ChunChen Yanwei
Regarding the complexity and inconsistency of results in existing evaluation methods of mine cooling system, this paper clarifies the advantages, disadvantages and application of various mine cooling systems through principle analysis, and divides all the cooling systems into air-cooling, ice-cooling and water-cooling according to the transportation of cold energy. On this basis, the paper proposes a simple and efficient evaluation method for mine cooling system. The first index of this method is the air temperature at point C which is 15 m away from the return wind corner at working face. A cooling system will be judged ineligible if the air temperature at point C is above 30 °C during operation, because in this case, the combustible gases in coal will sharply overflow, inducing gas incidents. Based on the preliminary judgment of the first index, another two evaluation indexes are proposed based on the cooling ability and dehumidification of an airflow volume of 1000 m3/min at point C to evaluate the investment and operation cost of mine cooling system. This evaluation method has already been successfully applied in the cooling system design of Zhangshuanglou coal mine.
Guo PingyeWang YanweiDuan MengmengPang DongyangLi Nan
