Study On The Barrier Water Mechanism Of Floor Collapse Column In Sima Coal

Collapse column water inrush is a typical mine water inrush problem caused by tectonic anomalies, andis also the most harmful.For a long time,study of collapse column water inrush is mainly onwater conductivity and mining-caused activation of collapse column. However, the research on water barrier of collapse columnitselfis less, so it not only has a very high scientific value, also has a great useful to ensure the safety and resource conservation of coal mining. In this paper,on the basis of study the development situation and rich water of collapse column in sima coal, using the method of theoretical analysis, numerical simulation,laboratory experiment and field test has a system research on the ability and mechanism of collapse column water barrier, Following results were obtained:(1) Make clear that collapse column in sima coal are no water or local water and also has the ability of water barrier, distribution rule is most in deeply buried and less in shallow, also presented in groups, the degree of compaction and cementation is better and has strong ability of resisting water.(2) Based on the theory of elastic mechanics and fracture mechanics, mechanical model of Collapse Column water inrush was established to get the stress expression in collapse column, then get the critical pressure expression which means propagation and coalescence of crack in collapse column then lead to the water inrush.(3) Internal compaction of collapse column is well and has a certain strength, Study the internal filling ingredient and pore structure of collapse column by using XRF and mercury experiment from the microscopic point, The results showed that the main ingredient is argillaceous and siliceous, cementation and fill level is good, cementation and filling better; With increasing of depth pore throat distribution gradually concentrated, permeability is also deteriorated,so collapse column barrier water capacity also gradually become strong.(4) Numerical simulations shows damage depth of complete floor is about 19 m and damage depth of containing collapse column floor is about 35 m, destruction depth coincide with the measured data of adjacent mine, so it can provide guidance for the actual production.(5)It shows that collapse column has good barrier water capacity by laboratory permeability test of collapse column samples and site water-blocking ability test of collapse column. Laboratory tests shows it can reached 2-2.5Mpa/m and field test is 1.5-2MPa/m. Combined with floor damage depth of containing collapse column get by numerical simulations, then it can provide a scientific basis to guide making rational use of water capacity barrier of collapse column.