Quantitative Evaluation of Electrical Resistivity CT Image in Mine Water Inrush Process Based on Image Entropy

Aiming at the qualitative analysis of resistivity CT image by intuitive judgment alone, we put forward a quantitative evaluation method based on image entropy to quantitatively analyze real-time change of image information.A simplified geo-electric model for water inrush process due to collapse columns from coal seam floor is built.And numerical forward modeling for simulating the water inrush process monitored by ERT method is executed by the Finite Element Method.The response characteristics of image entropy to the water inrush process are analyzed,by which the precursory information of water inrush is captured successfully.The image entropy method is used to evaluate the CT image in mine roof water inrush model test. And the precursory information of water inrush is captured,which is 574 s ahead of the inrush time.By analyzing the response characteristics of image entropy in numerical modeling and model test,we obtain an important conclusion,that is:"the catastrophe of image entropy is essentially the response to the catastrophe event that results in fundamental change to electric conductivity in strata or coal seam".By using the quantitative evaluation method with image entropy,the jam of the initial disturbance to analysis and capturing the precursory information is suppressed to a certain extent,and the impact of catastrophe event is amplified,making the success probability and reliability of precursory information capturing effectively improved.