Judgment technique for over-exploration of water-conducting channel based on process analysis and fuzzy comprehensive evaluation
The geological conditions of the North China-type coalfields are complicated,and a large number of water-conducting channels are formed by the tectonic cutting of the coal seam base plate,whose detection and identification have always been the key point and diffi-culty in water damage prevention and control.Based on the multi-branch directional long drilling overrun investigation,the water-conduct-ing channel identification technology combining process analysis and fuzzy comprehensive evaluation was constructed.Firstly,in the pro-cess of overpassing exploration,six evaluation indexes were selected,named drilling time recording,drilling fluid consumption,γ record-ing,rock chip recording,water pressure test and injectability and the construction process was divided into 16 working conditions,accord-ing to which a comprehensive analysis flowchart was set up to make a qualitatively judgement on whether the sample points were water-conducting.Secondly,the six indicators are quantified and graded by drilling speed,drilling fluid consumption,γ value,non-tuff propor-tion,unit grouting volume,and grouting volume,the weights of the indicators were determined by using the over-weighting method,and a three-level quantitative identification was made based on the fuzzy theory and the maximum membership principle to determine whether the sample point was water-conducting.Lastly,the technique was used to carry out a comprehensive process analysis and fuzzy compre-hensive evaluation of 13 points in the 15031 working face of Zhaogu No.1 mine,of which 10 points had a high probability of water con-duction and 3 points had a low probability of water conduction.This technique constructed a system of indicators for identifying water-conducting channels,and carried out quantitative grading and comprehensive evaluation,which improved the identification of water-con-ducting channels in the coalbed base plate.
over-explorationwater-conducting channelfuzzy comprehensive evaluationmine water disaster
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