Characteristics And Forming Mechanism Of Karstic Collapse Columns (belts) At Coalfield In Huainan

Karst collapse column as a special kind of geologic body in coal not only effects roadway arrangement, roadway stability and the quantity of coal mining, but also may because water inrush on coal face, which poses a great threat to the safety of workers. The research on the characteristics and forming mechanism of karst collapse column is helpful for coal geologists to make correct judgement on karst collapse column, and then prepare in advance, to prevent coalfield disasters effectively and reduce the losses from collapse column. Thus this research has important theoretical and practical significance. Based on many relative literature about coalmine karst collapse column, this paper was performed using the theoretical analysis and field application to analyse the date of coalfield-geology, hydrogeology, chemical character and collapse column underground in Huainan which is located in karst collapse column area. According to the 3D seismic data and image in columns, analyse morphological and internal filling characteristics of the karst collapse column. By analysing the data of groundwater chemical and the location of water inrush in Xieqiao mine, combines the DTM Function with principal component analysis of GIS, to study the sphere of influence, the character of water quanlity and quantity, and the temperature changes in the affected zone. And systematic summary of the Huainan karst collapse columns (belts) with three layers of different hydraulic conductivity. By analyzing the characteristic of karst collapse column, combines the geological evolution process with the groundwater activity, to study the forming mechanism of karst collapse column. The analysis above are of important guidance for preventing geology problems. The results of this research are summarized below:(1) The plant shapes of the most karst collapse column are elongated, and the general trend in NW-SE, cross sections show small top and big bottom, the top under the bedrock surface for the most karst collapse column;(2) Most karst collapse column develop from Cambrian limestone and with large collapsing area, and the adjoining rock crack highly developed;(3) The hydraulic conductivity of karst collapse column in each coal is different, and the lower the coal seam, the greater the hydraulic conductivity. It is necessary to pay special attention to it and then prevent water inrush; (4) With a wide affection and obvious variation of hydrochemical character in the karst collapse column, only notice the variety of coal water and prepare in advance can we avoid water inrushing;(5) A series of extension fault along NW direction developed in Huainan mine field after three tectonic processes(geological structure), then evolve into karst caves extending down to Cambrian limestone because of the long-term corrosion of SE-NW groundwater, finally form the collapse column due to gravity.